CN115561316A - Ultrasonic detection method and device for simultaneously measuring high-precision stress and thickness - Google Patents

Ultrasonic detection method and device for simultaneously measuring high-precision stress and thickness Download PDF

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CN115561316A
CN115561316A CN202211340887.XA CN202211340887A CN115561316A CN 115561316 A CN115561316 A CN 115561316A CN 202211340887 A CN202211340887 A CN 202211340887A CN 115561316 A CN115561316 A CN 115561316A
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周冰
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Suzhou Aiserti Technology Co ltd
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    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/043—Analysing solids in the interior, e.g. by shear waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G01B17/02—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/041—Analysing solids on the surface of the material, e.g. using Lamb, Rayleigh or shear waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/223—Supports, positioning or alignment in fixed situation
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    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/023—Solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
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    • G01N2291/02827—Elastic parameters, strength or force
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    • G01—MEASURING; TESTING
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    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract

The invention provides an ultrasonic nondestructive testing method and device for simultaneously measuring high-precision stress and thickness, comprising the following steps: fixing the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-to-one or one-to-two mode; the ultrasonic transmitting probe generates ultrasonic waves which are obliquely incident on the surface of the material, and the ultrasonic receiving probe receives ultrasonic signals; and processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the transceiving mode of the ultrasonic probe. The ultrasonic stress and ultrasonic thickness detection device solves the problems that the existing ultrasonic stress and ultrasonic thickness detection respectively adopt different ultrasonic probe forms, cannot simultaneously measure and can only be respectively operated.

Description

Ultrasonic detection method and device for simultaneously carrying out high-precision stress and thickness measurement
Technical Field
The invention belongs to the field of nondestructive ultrasonic technology detection, and particularly relates to an ultrasonic nondestructive detection method and device for simultaneously carrying out high-precision stress and thickness measurement.
Background
The pressure vessel and the pipeline are widely applied to modern industry, and along with the annual increase of the service life of metal materials, the pipeline and the pressure vessel enter a stage with multiple accidents, the pressure value of the materials and the thinning degree of the materials in the using process need to be measured and monitored, namely, the thickness needs to be measured, and therefore effective and safe operation of the pipeline and the pipeline is guaranteed. The method adopted at present is based on the acoustoelastic theory by adopting an ultrasonic stress meter, and measuring the change of the coming time of ultrasonic critical refraction longitudinal waves by adopting a transmitting-receiving probe so as to calculate the stress of the surface of the material; the thickness measurement is that a thickness gauge is adopted, a transmitting-receiving integrated probe is perpendicular to the surface of the material, ultrasonic waves are transmitted to the bottom surface by the transmitting-receiving integrated probe and are reflected back to an original ultrasonic probe, and by measuring the propagation time of the ultrasonic waves from transmission to reception, half of the product of the propagation time and the sound velocity is the thickness of the measured material. However, the thickness gauge and the ultrasonic stress gauge are adopted for measuring the thickness and the stress respectively, different devices and probes are needed, the operation is troublesome, the process is complicated, the efficiency is low, the simultaneous detection cannot be realized, some special places in the field even need to climb up to make a round trip to detect, and the experience is influenced. In addition, the receiving and transmitting integrated probe used by the thickness measuring probe is usually handheld during field detection, the thickness measuring precision is low due to poor fixing stability, and the maximum thickness measuring precision is only 0.01mm.
In order to overcome the problem that different equipment is needed for ultrasonic thickness measurement and ultrasonic stress measurement, ultrasonic stress acquisition equipment and an ultrasonic thickness measurement instrument can be integrated through program development, and one equipment has both the ultrasonic stress acquisition function and the ultrasonic thickness measurement function; however, in the ultrasonic stress detection, an ultrasonic transmitting probe and an ultrasonic receiving probe adopt a transmitting-receiving oblique incident material and receive ultrasonic signals for processing, and in the ultrasonic thickness measurement, a single transmitting-receiving integrated ultrasonic probe vertical incident material is adopted to process by means of a vertically reflected bottom echo signal. Although the ultrasonic stress and ultrasonic thickness measurement functions can be integrated by one device, the ultrasonic stress adopts a form of one-sending-one-receiving oblique incidence, and the ultrasonic thickness measurement adopts a form of vertical incidence of the ultrasonic probe integrating sending and receiving, so that when detection is carried out due to the two different ultrasonic probe forms, different ultrasonic probes still need to be replaced and connected, device parameters need to be reset, repeated operation detection is carried out, the ultrasonic stress and thickness can not be measured conveniently and rapidly, and the problem of inaccurate precision of the handheld sending-receiving integrated probe still can not be improved.
The ultrasonic thickness measuring device integrates thickness measuring and stress measuring functions in the prior art, the ultrasonic stress and the measured thickness cannot be measured simultaneously due to different testing principles and different receiving and sending modes of the ultrasonic probes, different ultrasonic probe modes need to be replaced and connected, different parameter settings are used, the ultrasonic stress and the ultrasonic thickness measuring can only be operated independently, the ultrasonic thickness measuring precision is not accurate enough, and an effective solution is not provided at present.
Disclosure of Invention
In order to achieve the above object, according to an aspect of an embodiment of the present invention, there is provided an ultrasonic nondestructive testing method and apparatus for simultaneously performing high-precision stress and thickness measurement, including: fixing the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-pitch and one-pitch or one-pitch and double-pitch mode; the ultrasonic transmitting probe generates ultrasonic waves which are obliquely incident on the surface of the material, and the ultrasonic receiving probe receives ultrasonic signals; and processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the transceiving mode of the ultrasonic probe.
Further, the ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, the oblique incident angle of the ultrasonic wave is ensured to be less than or equal to a first critical angle, and the incident angle is as follows: 0< theta <45 deg..
Furthermore, when the one-shot-one-shot mode is implemented, the connecting piece is provided with an inclined plane forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded hole for installing the ultrasonic transmitting probe and the ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; FIG. 1 is a schematic diagram showing the connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a pitch-catch type; when the one-shot-double-shot mode is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface and a threaded hole channel for installing an ultrasonic transmitting probe and an ultrasonic receiving probe, wherein the vertical inclined plane is provided with the threaded hole channel for installing a second ultrasonic receiving probe; fig. 2 is a schematic view showing the connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a one-shot and two-shot mode.
Furthermore, the ultrasonic transmitting probe receives a pulse excitation waveform transmitted by the ultrasonic transmitting circuit to generate ultrasonic waves, and the generated ultrasonic waves are incident to the surface of the material from the organic glass and accord with the Snell law; ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, the ultrasonic signals transmitted along the surface of the material are sequentially received by ultrasonic receiving probes with the same angle, and the ultrasonic signals are acquired through an ultrasonic acquisition module connected with the ultrasonic receiving probes; if the ultrasonic wave is in a one-transmitting and two-receiving form, the ultrasonic wave is received by the first ultrasonic receiving probe and the second ultrasonic receiving probe in sequence, a schematic diagram of the path of the ultrasonic wave signal in the material in the one-transmitting and one-receiving form is shown in fig. 3, and a schematic diagram of critical refraction longitudinal waves and bottom surface reflection waves in the ultrasonic wave signal in the one-transmitting and one-receiving form is shown in fig. 4.
Further, the method for processing ultrasonic signals by ultrasonic thickness measurement comprises the following steps: determining the temporary time T0 from a critical refraction longitudinal wave signal and the temporary time Tn from an nth surface wave signal reflected by the bottom surface in the acquired ultrasonic signals, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure DEST_PATH_IMAGE001
measuring the thickness of the material, wherein H is the thickness of the workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave in the medium, and n (n =1,2,3, 4.) is the serial number of the surface wave generated by the nth reflection of the selected ultrasonic wave incident on the material and the bottom surface to the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
Wherein, the ultrasonic thickness measuring formula can be transformed into:
Figure DEST_PATH_IMAGE002
Figure DEST_PATH_IMAGE003
。
the thickness measurement formula can measure the accurate propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of knowing the accurate thickness H of the workpiece material:
Figure DEST_PATH_IMAGE004
。
further, the method for processing ultrasonic signals by ultrasonic measurement stress under the mode of one-shot-one-shot oblique incidence of the ultrasonic probe comprises the following steps: determining the difference value delta T0= T0 '-T0 between T0' corresponding to the critical refraction longitudinal wave in the stress-free calibration process and T0 corresponding to the critical refraction longitudinal wave in the stress test process, and substituting the delta T0 into an ultrasonic stress formula:
Figure DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
Further, the method for detecting ultrasonic stress processing ultrasonic signals by the ultrasonic probe through one-shot double-shot oblique incidence comprises the following steps: determining a difference value between a critical refraction longitudinal wave in an ultrasonic signal received by a second ultrasonic receiving probe and a critical refraction longitudinal wave in an ultrasonic signal received by a first ultrasonic receiving probe during stress-free calibration as a calibration initial value T0'; determining a difference value between a critical refraction longitudinal wave in an ultrasonic signal of the second ultrasonic receiving probe and a critical refraction longitudinal wave in an ultrasonic signal of the first ultrasonic probe during a stress test as a test value T0; determining the difference value delta T0= T0 '-T0 between T0' corresponding to the critical refracted longitudinal wave in the non-stress calibration process and T0 corresponding to the critical refracted longitudinal wave in the stress test process during the one-shot and two-shot stress measurement process, and substituting the delta T0 into an ultrasonic stress formula:
Figure 268048DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
Further, the method for processing the ultrasonic signal to determine the coming time of the critical refracted longitudinal wave and/or the surface wave reflected by the bottom surface comprises the following steps: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control method to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control method comprises the steps that at least one movable horizontal vernier or a peak value proportion gate is used as a threshold value, and when the peak intensity in a waveform data segment exceeds the gate threshold value, the corresponding time of the coming waveform is considered; fig. 5 is a schematic diagram showing a method for selecting a waveform data segment by a vertical cursor and determining the waveform arrival time by a horizontal cursor, and fig. 6 is a schematic diagram showing a method for selecting a waveform data segment by a frame and determining the waveform arrival time by a horizontal cursor.
The method can be used for measuring the thickness of the workpiece material independently, can be used for measuring the stress and the thickness of the material respectively under the condition of not changing the receiving and transmitting mode of the ultrasonic probe, and can also be used for measuring the stress and the thickness of the material simultaneously under the condition of not changing the receiving and transmitting mode of the ultrasonic probe. The ultrasonic probe transceiving mode is not changed, which is the mode of maintaining the same ultrasonic thickness measurement and ultrasonic stress for transceiving and position maintaining of the probe.
The accuracy of stress and thickness measurement can be further improved by repeatedly acquiring and averaging, wherein the repeatedly acquiring comprises repeatedly acquiring ultrasonic signals to average and then evaluating stress and thickness measurement, and the repeatedly acquiring comprises repeatedly measuring stress and thickness and then averaging.
Furthermore, a time difference value delta T0 corresponding to the time when the LCR wave comes during the test and the stress-free calibration time is determined, the LCR wave during the stress-free calibration time and the LCR wave during the test can be placed in the same graph, a horizontally moving vernier is used as a valve threshold, the time when the LCR wave comes is considered when the waveform value exceeds the threshold range, and the difference value of the two waveforms is the delta T0.
In order to achieve the above object, according to another aspect of the embodiments of the present invention, there is provided an ultrasonic nondestructive testing apparatus that simultaneously performs high-precision stress and thickness measurements. The invention provides an ultrasonic nondestructive testing device for simultaneously measuring high-precision stress and thickness, which comprises: a screen; the ultrasonic probe module fixes the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-transmitting-one-receiving or one-transmitting-two-receiving mode; the ultrasonic transmitting module is used for connecting the ultrasonic transmitting probe to generate ultrasonic waves to obliquely enter the surface of the material; the ultrasonic receiving module is used for connecting the ultrasonic receiving probe to receive the ultrasonic signals; and the signal processing module is used for processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the receiving and transmitting mode of the ultrasonic probe.
Further, the ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, the oblique incident angle of the ultrasonic wave is ensured to be less than or equal to a first critical angle, and the incident angle is as follows: 0< theta <45 deg..
Furthermore, when the one-shot-one-shot mode is implemented, the connecting piece is provided with an inclined plane forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded hole for installing the ultrasonic emission probe and the ultrasonic receiving probe, the ultrasonic emission probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; FIG. 1 is a schematic diagram showing the connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a pitch-catch mode; when the one-shot double-shot mode is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface and a threaded hole for installing an ultrasonic transmitting probe and an ultrasonic receiving probe, which is arranged on the vertical inclined plane, one more inclined plane forming an angle theta with the bottom surface is arranged on one side of the ultrasonic receiving probe, the threaded hole for installing a second ultrasonic receiving probe is arranged on the vertical inclined plane, the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; fig. 2 is a schematic view showing the connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a one-shot and two-shot mode.
Furthermore, the ultrasonic transmitting probe receives the pulse excitation waveform transmitted by the ultrasonic transmitting circuit to generate ultrasonic waves, and the generated ultrasonic waves are incident to the surface of the material from the organic glass and accord with Snell law; the ultrasonic wave is incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic wave is reflected to the upper surface each time, the ultrasonic wave signals transmitted along the surface of the material are sequentially received by ultrasonic wave receiving probes with the same angle, and the ultrasonic wave signals are collected through a connected ultrasonic wave collecting module; if the ultrasonic wave is in a one-transmitting and two-receiving form, the ultrasonic wave is sequentially received by the first ultrasonic receiving probe and the second ultrasonic receiving probe, a schematic diagram of the path of the ultrasonic wave signal in the material in the one-transmitting and one-receiving form is shown in fig. 3, and a schematic diagram of critical refraction longitudinal waves and bottom surface reflection waves in the ultrasonic wave signal in the one-transmitting and one-receiving form is shown in fig. 4.
Further, the module for ultrasonic thickness measurement processing ultrasonic signals in the one-pitch-one-pitch or one-pitch-two-pitch oblique incidence mode includes: determining the temporary time T0 from a critical refraction longitudinal wave signal and the temporary time Tn from an nth surface wave signal reflected by the bottom surface in the acquired ultrasonic signals, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 716346DEST_PATH_IMAGE001
measuring the thickness of the material; h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave in the medium, and n (n =1,2,3, 4.) is the serial number of the surface wave generated by the nth reflection of the selected ultrasonic wave incident on the material and the bottom surface to the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so that H thickness measurement can also be accurate to nanometer level.
Wherein, the ultrasonic thickness measuring formula can be transformed into:
Figure 761663DEST_PATH_IMAGE002
Figure 422451DEST_PATH_IMAGE003
。
the thickness measurement formula can measure the accurate propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of knowing the accurate thickness H of the workpiece material:
Figure 502403DEST_PATH_IMAGE004
。
further, the module for processing the ultrasonic signal by the ultrasonic measuring stress under the mode of transmitting and receiving the oblique incidence by the ultrasonic probe comprises: determining the difference value delta T0= T0 '-T0 between T0' corresponding to the critical refraction longitudinal wave in the stress-free calibration process and T0 corresponding to the critical refraction longitudinal wave in the stress test process, and substituting the delta T0 into an ultrasonic stress formula:
Figure 590444DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
Further, the module for detecting ultrasonic stress processing ultrasonic signals by the one-shot double-shot oblique incidence of the ultrasonic probe comprises: determining a difference value between a critical refraction longitudinal wave in an ultrasonic signal received by a second ultrasonic receiving probe and a critical refraction longitudinal wave in an ultrasonic signal received by a first ultrasonic receiving probe during stress-free calibration as a calibration initial value T0'; determining a difference value between a critical refraction longitudinal wave in an ultrasonic signal of the second ultrasonic receiving probe and a critical refraction longitudinal wave in an ultrasonic signal of the first ultrasonic probe during a stress test as a test value T0; determining the difference value delta T0= T0 '-T0 between T0' corresponding to the critical refraction longitudinal wave in the non-stress calibration process and T0 corresponding to the critical refraction longitudinal wave in the stress test process during the one-shot and two-shot stress measurement process, and substituting the delta T0 into an ultrasonic stress formula:
Figure 123057DEST_PATH_IMAGE005
and calculating stress values, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
Further, the module for determining the arrival time of the critical refracted longitudinal wave or the bottom surface-emitted surface wave in the module for processing ultrasonic signals comprises: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control module to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control module adopts at least one movable horizontal vernier or a peak value proportion gate as a threshold value, and considers the time corresponding to the arrival of the waveform when the peak intensity in the waveform data section is greater than the gate threshold value; fig. 5 is a schematic diagram illustrating a method for selecting a waveform data segment by a vertical cursor and determining a waveform arrival time by a horizontal cursor, and fig. 6 is a schematic diagram illustrating a method for selecting a waveform data segment by a frame and determining a waveform arrival time by a horizontal cursor.
The module can be used for measuring the thickness of the workpiece material independently, can also be used for measuring the stress and the thickness of the material respectively under the condition of not changing the receiving and transmitting mode of the ultrasonic probe, and can also be used for measuring the stress and the thickness of the material simultaneously under the condition of not changing the receiving and transmitting mode of the ultrasonic probe. The ultrasonic probe transceiving mode is not changed, and the mode of probe transceiving and position maintaining which keeps the ultrasonic thickness measurement and the ultrasonic stress the same is adopted.
The accuracy of stress and thickness measurement can be further improved through a functional module for repeatedly acquiring and averaging, wherein repeated acquisition comprises repeated acquisition of ultrasonic signals for averaging and then stress and thickness measurement, and repeated measurement of stress and thickness for multiple times for averaging.
Furthermore, a function module for determining a time difference value delta T0 corresponding to the time when the LCR wave comes during the test and the stress-free calibration time is determined, the LCR wave during the stress-free calibration time and the LCR wave during the test can be placed in the same graph, a horizontally moving vernier is used as a valve threshold, the time when the LCR wave comes is determined when the waveform value exceeds the threshold range, and the difference value of the two waveforms is the delta T0.
Compared with the prior ultrasonic thickness measurement method for the surface of the receiving-transmitting integrated vertical incidence material, the invention also provides a brand new method for measuring the thickness of the material by transmitting and receiving inclined incidence, which comprises the following steps: fixing an ultrasonic transmitting probe and an ultrasonic receiving probe on a connecting piece at a specific angle in a form of transmitting and receiving; the ultrasonic transmitting probe generates ultrasonic waves which are obliquely incident on the surface of the material, and the ultrasonic receiving probe receives ultrasonic signals; and processing the ultrasonic signals to measure the thickness of the material.
The ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle of ultrasonic waves is not more than a first critical angle, and the incident angle is as follows: 0< θ <45 °; the connecting piece is provided with an inclined plane forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded pipeline for installing the ultrasonic transmitting probe and the ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent.
Furthermore, the ultrasonic transmitting probe receives the pulse excitation waveform transmitted by the ultrasonic transmitting circuit to generate ultrasonic waves, and the generated ultrasonic waves are incident to the surface of the material from the organic glass and accord with the Snell law; ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, ultrasonic echo signals transmitted along the surface of the material are sequentially received by ultrasonic receiving probes with the same angle, and the ultrasonic signals are acquired through an ultrasonic acquisition module; fig. 3 is a schematic diagram illustrating the path of an ultrasonic signal in a material in a pitch-catch mode.
Further, the method for processing ultrasonic signals by ultrasonic thickness measurement comprises the following steps: determining the temporary time T0 from a critical refraction longitudinal wave signal and the temporary time Tn from an nth surface wave signal reflected by the bottom surface in the acquired ultrasonic signals, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 587536DEST_PATH_IMAGE001
measuring the thickness of the material, wherein H is the thickness of the workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave in the medium, and n (n =1,2,3, 4.) is the ultrasonic wave incident material selected for measurementThe n-th reflection of the material and the bottom surface returns the serial number of the surface wave generated on the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so that H thickness measurement can also be accurate to nanometer level.
Wherein, the ultrasonic thickness measuring formula can be transformed into:
Figure 787574DEST_PATH_IMAGE002
Figure 46517DEST_PATH_IMAGE003
。
the thickness measuring formula can measure the accurate propagation speed of the ultrasonic wave in the medium in a variable way under the condition of knowing the accurate thickness H of the workpiece material:
Figure 66425DEST_PATH_IMAGE004
。
further, the method for processing the ultrasonic signal to determine the coming time of the critical refracted longitudinal wave or the surface wave reflected by the bottom surface comprises the following steps: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control method to determine the coming time of waveforms corresponding to critical refraction longitudinal waves and surface waves; the gate control method comprises the steps that at least one movable horizontal vernier or a peak value proportion gate is used as a threshold value, and when the peak intensity in a waveform data section is larger than the gate threshold value, the corresponding time of the coming waveform is considered; fig. 5 is a schematic diagram showing a method for selecting a waveform data segment by a vertical cursor and determining the waveform arrival time by a horizontal cursor, and fig. 6 is a schematic diagram showing a method for selecting a waveform data segment by a frame and determining the waveform arrival time by a horizontal cursor.
The accuracy of stress and thickness measurement can be further improved in an averaging mode through repeated acquisition, wherein the repeated acquisition comprises repeated acquisition of ultrasonic signals for averaging and then stress and thickness measurement, and also comprises repeated measurement of stress and thickness and then averaging.
In order to realize the purpose, the invention also discloses an ultrasonic thickness measuring device which is completely different from the ultrasonic thickness measuring device for the surface of a single ultrasonic probe which is integrated with a transceiver and vertically incident to the material.
The invention provides a brand-new device for measuring the thickness of a material by oblique incidence of a first transmission and a second transmission, which comprises: a screen; the ultrasonic probe module fixes the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-transmitting-one-receiving or one-transmitting-two-receiving mode; the ultrasonic transmitting module is used for connecting the ultrasonic transmitting probe to generate ultrasonic waves to obliquely enter the surface of the material; the ultrasonic receiving module is used for connecting the ultrasonic receiving probe to receive the ultrasonic signal; and the signal processing module is used for processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the receiving and transmitting mode of the ultrasonic probe.
An ultrasonic transmitting probe and an ultrasonic receiving probe in the ultrasonic probe module are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the ultrasonic receiving probe and the surface of a material is theta, and the oblique incident angle of ultrasonic waves is ensured to be less than or equal to a first critical angle, and the incident angle is as follows: 0< θ <45 °; the connecting piece is provided with an inclined plane forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded channel for installing the ultrasonic transmitting probe and the ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent.
Furthermore, the ultrasonic transmitting probe receives the pulse excitation waveform transmitted by the ultrasonic transmitting circuit to generate ultrasonic waves, and the generated ultrasonic waves are incident to the surface of the material from the organic glass and accord with the Snell law; ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, ultrasonic echo signals transmitted along the surface of the material are sequentially received by ultrasonic receiving probes with the same angle, and the ultrasonic signals are acquired through an ultrasonic acquisition module; fig. 3 is a schematic diagram illustrating the path of an ultrasonic signal in a material in a pitch-catch mode.
Further, the function of the ultrasonic signal processing module in the ultrasonic thickness measuring device in the form of one-pitch and one-receive or one-pitch and double-receive oblique incidence comprises: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal reflected by the nth bottom surface, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 69016DEST_PATH_IMAGE001
the thickness of the material is measured, and the ultrasonic thickness measurement formula can be converted into the following formula according to a trigonometric function rule:
Figure 857981DEST_PATH_IMAGE002
Figure 553404DEST_PATH_IMAGE003
。
the thickness measuring module can measure the accurate propagation speed of ultrasonic waves in a medium in a variable manner under the condition of knowing the accurate thickness H of a workpiece material:
Figure 60609DEST_PATH_IMAGE004
。
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the critical refraction longitudinal wave generated on the surface of the ultrasonic incident material and the multiple reflection of the bottom surface back to the upper surface; in the module, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
Further, the module for determining the arrival time of the critically refracted longitudinal wave or the bottom surface-emitted surface wave in the module for processing ultrasonic signals comprises: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected by adopting a movable vertical vernier line, a square frame, or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control module to determine the coming time of waveforms corresponding to critical refraction longitudinal waves and surface waves; the gate control module adopts at least one movable horizontal vernier or a peak value proportion gate as a threshold value, and when the peak intensity in the waveform data section is greater than the gate threshold value, the corresponding time of the waveform coming is considered; fig. 5 is a schematic diagram showing a method for selecting a waveform data segment by a vertical cursor and determining the waveform arrival time by a horizontal cursor, and fig. 6 is a schematic diagram showing a method for selecting a waveform data segment by a frame and determining the waveform arrival time by a horizontal cursor.
The accuracy of thickness measurement can be further improved in an averaging mode through repeated acquisition, wherein the repeated acquisition comprises repeated acquisition of ultrasonic signals for averaging and then thickness measurement, and also comprises repeated measurement for averaging after the thickness is repeatedly measured for multiple times.
The invention also provides a formula for measuring the thickness of the material by ultrasonic oblique incidence in a pitch-catch mode, which is characterized in that:
Figure 601312DEST_PATH_IMAGE001
(ii) a In the formula, theta is an oblique incident angle of the ultrasonic wave; v is the ultrasonic wave propagation speed, n (n =1,2,3, 4.) is the serial number of the nth surface wave generated by the reflection of the bottom surface back to the upper surface after the selected ultrasonic wave is incident on the material; the equation can be transformed according to trigonometric function rules:
Figure DEST_PATH_IMAGE006
Figure DEST_PATH_IMAGE007
。
drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. In the drawings: fig. 1 is a schematic diagram showing the connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a one-shot mode.
Fig. 2 is a schematic diagram showing the connection between an ultrasonic emission probe and an ultrasonic receiving probe in a one-shot and two-shot mode.
Fig. 3 is a schematic diagram illustrating the path of an ultrasonic signal in a material in a pitch-catch mode.
FIG. 4 is a schematic diagram of critical refraction longitudinal waves and bottom reflection waves in an ultrasonic signal in a transmit-receive mode.
FIG. 5 is a schematic diagram of a method for selecting a waveform data segment by a vertical cursor and determining the arrival time of a waveform by a horizontal cursor.
FIG. 6 is a schematic diagram of a method for determining the arrival time of a waveform by selecting waveform data segments and horizontal cursors in a square frame.
Detailed Description
It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
It is to be understood that the terms "first", "second" and "third" in the description and claims of the present invention and the above-described drawings
Two, etc. are used to distinguish between similar objects and not necessarily to describe a particular order or sequence. It should be understood that such use is of
May be interchanged where appropriate in order to facilitate the embodiments of the invention described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The embodiment of the invention provides an ultrasonic nondestructive testing method for simultaneously measuring high-precision stress and thickness, which comprises the following steps: fixing the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-to-one or one-to-two mode; the ultrasonic transmitting probe generates ultrasonic waves which are obliquely incident to the surface of the material, and the ultrasonic receiving probe receives ultrasonic signals; and processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the transceiving mode of the ultrasonic probe.
The ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, the Snell law is satisfied, and the oblique incident angle of ultrasonic waves is not more than a first critical angle, the incident angle is as follows: 0< theta <45 deg..
When the form of sending and receiving is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface, the vertical inclined planes are provided with threaded pipelines for installing an ultrasonic transmitting probe and an ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; the ultrasonic wave transmitting circuit transmits a pulse waveform, and an ultrasonic wave is generated by the ultrasonic transmitting probe after excitation; the generated ultrasonic waves are emitted to the surface of the material from the organic glass, and the Snell law is met; ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, ultrasonic echo signals transmitted along the surface of the material are sequentially received by ultrasonic receiving probes with the same angle, and the ultrasonic signals are acquired through an ultrasonic acquisition module; fig. 1 is a schematic diagram showing a connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a one-transmission and one-reception mode, and fig. 4 is a schematic diagram showing critical refraction longitudinal waves and bottom surface reflection waves in an ultrasonic signal in a one-transmission and one-reception mode.
The existing ultrasonic thickness measuring method and equipment adopt a single ultrasonic probe which integrates receiving and transmitting into a whole to vertically irradiate the surface of a material, and half of the product of a bottom echo signal and ultrasonic sound velocity is calculated by timing the time of the bottom echo signal, namely the thickness of the workpiece material. The related principle and method of ultrasonic thickness measurement in a pitch-catch-pitch incidence mode are not found in the current published data.
The invention provides a brand-new method for processing ultrasonic signals by ultrasonic thickness measurement in a pitch-catch oblique incidence mode, which comprises the following steps: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal reflected by the nth bottom surface, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 41520DEST_PATH_IMAGE001
according to the trigonometric function law, the transformation is as follows:
Figure 907845DEST_PATH_IMAGE002
Figure 902346DEST_PATH_IMAGE003
。
the thickness measurement formula can measure the accurate propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of knowing the accurate thickness H of the workpiece material:
Figure 246740DEST_PATH_IMAGE004
。
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the critical refraction longitudinal wave generated on the surface of the ultrasonic wave incident material and the multiple reflection of the bottom surface back to the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
The method for processing the ultrasonic signal by ultrasonic measurement stress comprises the following steps: determining a difference value delta T0 between the critical refraction longitudinal wave in the stress-free calibration process and the T0 corresponding to the critical refraction longitudinal wave in the stress test process, and substituting the delta T0 into an ultrasonic stress formula:
Figure 10296DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
The method for processing the ultrasonic signals to determine the coming time of the critical refracted longitudinal wave or the surface wave reflected by the bottom surface comprises the following steps: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected by adopting a movable vertical vernier line, a square frame, or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control method to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control method comprises the steps that at least one movable horizontal vernier or a peak value proportion gate is used as a threshold value, and when the peak intensity in a waveform data section is larger than the gate threshold value, the corresponding time of the coming waveform is considered; fig. 5 is a schematic diagram showing a method for selecting a waveform data segment by a vertical cursor and determining the waveform arrival time by a horizontal cursor, and fig. 6 is a schematic diagram showing a method for selecting a waveform data segment by a frame and determining the waveform arrival time by a horizontal cursor.
For example, during testing, two pairs of movable vertical vernier lines are adopted, a waveform data segment where critical refraction longitudinal waves are located is selected from a first group of vernier lines, a surface wave data segment where the 1 st bottom surface reflection is selected from a second group of vernier lines, ultrasonic waves experience a V-shaped process in a workpiece material, at the moment, n =1, a peak value proportion gate is adopted to respectively determine the time T0 and T1 when LCR waves selected from the first group of vernier lines and surface waves RSW1 emitted from the bottom surface selected from the second group of vernier lines arrive, and the waveforms are substituted into an ultrasonic thickness measurement formula
Figure DEST_PATH_IMAGE008
H is solved; if the surface wave data segment reflected by the second bottom surface is selected by the second group of cursors, the ultrasonic waves experience two V-shaped histories in the workpiece material, and n =2 at the moment, and the two histories are substituted into the ultrasonic thickness measuring formula
Figure DEST_PATH_IMAGE009
H is solved; substituting the difference value delta T0 between the T0 corresponding to the first group of LCR waves when in test and the T0 corresponding to the LCR waves when in stress-free calibration into an ultrasonic stress formula:
Figure 578681DEST_PATH_IMAGE005
and calculating stress values, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
The method can be used for measuring the thickness of the workpiece material independently, can be used for measuring the stress and the thickness of the material respectively under the condition of not changing the receiving and transmitting mode of the ultrasonic probe, and can also be used for measuring the stress and the thickness of the material simultaneously under the condition of not changing the receiving and transmitting mode of the ultrasonic probe.
The accuracy of stress and thickness measurement can be further improved by repeatedly acquiring and averaging, wherein the repeatedly acquiring comprises repeatedly acquiring ultrasonic signals to average and then evaluating stress and thickness measurement, and the repeatedly acquiring comprises repeatedly measuring stress and thickness and then averaging.
The ultrasonic probe transceiving mode is not changed, and the mode of probe transceiving and position maintaining which keeps the ultrasonic thickness measurement and the ultrasonic stress the same is adopted.
The time difference value Delta T0 corresponding to the time when the LCR wave comes during the test and the stress-free calibration time is determined, the LCR wave during the stress-free calibration time and the LCR wave during the test can be arranged in the same graph, a horizontally moving vernier is used as a valve threshold, the time when the LCR wave comes is considered when the waveform value exceeds the threshold range, and the difference value of the two waveforms is the Delta T0.
Further implementing example thickness measurement and stress measurement, wherein an ultrasonic transceiving probe adopts 5MHZ, the angles of the inclined planes of the connecting pieces are all kept at 25 degrees with the bottom surface, a 2GHz acquisition board card is adopted to acquire ultrasonic signals, the time T0 and the time T1 of the arrival of LCR waves and RSW1 waves of the acquired ultrasonic signals are respectively determined, and V is the longitudinal wave propagation speed of the ultrasonic waves in the steel and is substituted into the thickness measurement formula to calculate the material thickness; and simultaneously determining the difference value delta T0 between the T0 value during the test and the T0 value during the stress-free calibration and the calibrated K sound time difference coefficient value, and substituting the difference value delta T0 and the calibrated K sound time difference coefficient value into the ultrasonic stress formula to calculate the stress value.
In a further implementation example, a workpiece with standard thickness is used for calibrating the ultrasonic propagation speed, the ultrasonic transceiving probe in a transceiving mode adopts 5MHZ, the angle of the inclined plane of the connecting piece is kept 25 degrees with the bottom surface, a 2GHz acquisition board card is used for acquiring ultrasonic signals, the time T1-T0 of LCR waves and RSW1 waves of the acquired ultrasonic signals is determined, and the time T1-T0 is substituted into a sound velocity measurement formula converted by the thickness measurement formula to calculate the longitudinal wave propagation speed of the ultrasonic in the workpiece material.
When the one-shot-double-shot mode is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface, a vertical inclined plane is provided with a threaded hole for installing an ultrasonic transmitting probe and an ultrasonic receiving probe, one side of the ultrasonic receiving probe is additionally provided with an inclined plane forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded hole for installing a second ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probes are respectively fixed on the connecting piece, the connecting piece is also provided with a magnet, and the magnet is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; fig. 2 is a schematic diagram showing the connection between an ultrasonic emission probe and an ultrasonic receiving probe in a one-shot and two-shot mode.
The ultrasonic wave transmitting circuit transmits a pulse waveform, and an ultrasonic wave is generated by the ultrasonic transmitting probe after excitation; the generated ultrasonic waves are emitted to the surface of the material from the organic glass, and the Snell law is met; the ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, the ultrasonic echo signals transmitted along the surface of the material are sequentially received by two ultrasonic receiving probes with the same angle respectively, and the ultrasonic signals are collected through two connected channel ultrasonic collection modules; the difference between the two is that the ultrasonic wave signal of the first channel connected with the first ultrasonic receiving probe receives the surface wave signals generated by the critical refraction longitudinal wave and the subsequent multiple bottom surface reflected waves in advance, and the surface wave signals generated by the critical refraction longitudinal wave and the subsequent multiple bottom surface reflected waves are later than the time of the first channel after the ultrasonic wave signal of the second channel connected with the second ultrasonic receiving probe receives the ultrasonic signal.
Determining the time when the critical refraction longitudinal wave in the ultrasonic signal received by any one of the two channels and the surface wave signal reflected by the bottom surface come, and determining and selecting the critical refraction longitudinal wave to be analyzed simultaneously and the waveform data segment where at least one surface waveform reflected by the bottom surface is located by adopting a movable vertical vernier line, a square frame, or numerical value input or mouse frame selection; analyzing the waveform data segment by adopting a gate control method to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control method comprises the steps of adopting at least one movable horizontal vernier or a peak value proportion gate as a threshold value, and considering the corresponding time when a waveform comes when the peak intensity in a waveform data segment is greater than the gate threshold value.
Determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal emitted by the nth bottom surface in the one-shot-double-shot mode, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 794899DEST_PATH_IMAGE001
according to the trigonometric function law, the transformation is:
Figure 942983DEST_PATH_IMAGE002
Figure 561046DEST_PATH_IMAGE003
。
the thickness measurement formula can measure the accurate propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of knowing the accurate thickness H of the workpiece material:
Figure 766244DEST_PATH_IMAGE004
。
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the critical refraction longitudinal wave generated on the surface of the ultrasonic incident material and the multiple reflection of the bottom surface back to the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
The method for processing the ultrasonic signal aiming at the ultrasonic measurement stress of the one-transmitting and two-receiving detection comprises the following steps: determining a difference value between a critical refraction longitudinal wave in an ultrasonic signal of the second ultrasonic receiving probe and a critical refraction longitudinal wave in an ultrasonic signal of the first ultrasonic probe during stress-free calibration as a calibration initial value T0; determining a difference value between a critical refraction longitudinal wave in the ultrasonic signal of the second ultrasonic receiving probe and a critical refraction longitudinal wave in the ultrasonic signal of the first ultrasonic probe during stress test as a test value T0; when the stress is measured in a one-sending and two-receiving mode, the difference value delta T0 between the test value T0 corresponding to the critical refraction longitudinal wave and the calibration initial value T0 is substituted into the ultrasonic stress formula:
Figure 469758DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
The method can be used for measuring the thickness of the workpiece material independently, can be used for measuring the stress and the thickness of the material respectively under the condition of not changing the receiving and transmitting mode of the ultrasonic probe, and can also be used for measuring the stress and the thickness of the material simultaneously under the condition of not changing the receiving and transmitting mode of the ultrasonic probe.
The accuracy of stress and thickness measurement can be further improved by repeatedly acquiring and averaging, wherein the repeatedly acquiring comprises repeatedly acquiring ultrasonic signals to average and then evaluating stress and thickness measurement, and the repeatedly acquiring comprises repeatedly measuring stress and thickness and then averaging.
The ultrasonic probe transceiving mode is not changed, and the mode of probe transceiving and position maintaining which keeps the ultrasonic thickness measurement and the ultrasonic stress the same is adopted.
The determining a difference Δ T0 between a test value T0 corresponding to the critical refracted longitudinal wave and the calibration initial value T0 during the one-shot and two-shot measurement of the stress includes: placing the ultrasonic signal of the first channel and the ultrasonic signal of the second channel in the same graph or placing the ultrasonic signals in the two graphs for display respectively when no stress is calibrated, using one or two horizontally moving cursors as a valve threshold, and respectively determining the time when the LCR wave comes when the waveform value of the critical refraction longitudinal wave exceeds the threshold range, wherein the difference value of the two waveforms is a calibration initial value T0; during testing, the ultrasonic signal of the first channel and the ultrasonic signal of the second channel are placed in the same graph or are placed in two graphs to be displayed respectively, one or two horizontally moving cursors are used as valve thresholds, the time when the LCR wave comes is determined when the waveform value of the critical refraction longitudinal wave exceeds the threshold range, and the difference value of the two waveforms is the test value T0.
In a further implementation example, thickness measurement and stress measurement are carried out, an ultrasonic transmitting and receiving probe adopts 5MHZ, the angle of the inclined plane of a connecting piece is kept to be 25 degrees with the bottom surface, a 2GHz acquisition board card is adopted to acquire ultrasonic signals, and the time of LCR waves and RSW2 waves of the ultrasonic signals acquired by one channel is determinedThe interval T2-T0, n is 2, V is the longitudinal wave propagation speed of the ultrasound in the steel, and the longitudinal wave propagation speed is substituted into the thickness measuring formula to calculate the thickness of the material; a difference value delta T0 between a test value T0 of a difference value between critical refracted longitudinal waves of two channel ultrasonic signals during one-shot double-shot stress measurement and an initial value T0 of a difference value between critical refracted longitudinal waves of two channel ultrasonic signals during calibration (the test value T0-the initial value T0) is substituted into an ultrasonic stress formula:
Figure 155954DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
In a further embodiment, a workpiece with a standard thickness is used for calibrating the ultrasonic propagation speed, an ultrasonic transmitting and receiving probe adopts 5MHZ in a transmitting and receiving mode, the angles of the inclined planes of connecting pieces are all kept to be 25 degrees with the bottom surface, a 2GHz acquisition board card is used for acquiring ultrasonic signals, the time T2-T0 of LCR waves and RSW2 waves of the acquired ultrasonic signals is determined, n =2 is taken and is substituted into a sound velocity measurement formula converted by the thickness measurement formula, and the accurate longitudinal wave propagation speed of the ultrasonic in the workpiece material is obtained.
In order to achieve the above object, according to another aspect of an embodiment of the present invention, there is provided an ultrasonic nondestructive testing apparatus for simultaneously performing high-precision stress and thickness measurement, the apparatus for processing waveform data in an ultrasonic signal according to the present invention includes: a screen;
the ultrasonic probe module fixes the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-transmitting-one-receiving or one-transmitting-two-receiving mode; the ultrasonic transmitting module is used for connecting the ultrasonic transmitting probe to generate ultrasonic waves to obliquely enter the surface of the material; the ultrasonic receiving module is used for connecting the ultrasonic receiving probe to receive the ultrasonic signal; and the signal processing module is used for processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the receiving and transmitting mode of the ultrasonic probe.
The ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle of ultrasonic waves is not more than a first critical angle, and the incident angle is as follows: 0< theta <45 deg..
When the mode of the ultrasonic probe module with one transmitting and one receiving is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface, the vertical inclined planes are provided with threaded pipelines for installing the ultrasonic transmitting probe and the ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; the ultrasonic wave transmitting module transmits a pulse waveform, and ultrasonic waves are generated by the ultrasonic transmitting probe after excitation; the generated ultrasonic waves are emitted to the surface of the material from the organic glass, and the Snell law is met; ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflection occurs between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, the ultrasonic echo signals transmitted along the surface of the material are sequentially received by ultrasonic receiving probes with the same angle, and the ultrasonic signals are acquired through an ultrasonic acquisition module connected with the ultrasonic receiving probes; fig. 1 is a schematic diagram showing the connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a pitch-catch mode.
The existing ultrasonic thickness measuring method and equipment adopt a single ultrasonic probe which integrates receiving and transmitting to vertically irradiate the surface of a material, and half of the product of a bottom echo signal and an ultrasonic sound velocity is calculated by timing the time of the bottom echo signal, namely the thickness of the workpiece material.
The related method and device for ultrasonic thickness measurement of the ultrasonic probe module in a pitch-catch-pitch incidence mode are not introduced in the prior published data. The invention provides a module for processing ultrasonic signals by ultrasonic thickness measurement in a brand-new mode of a pitch-catch-pitch incidence ultrasonic probe module, which comprises: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal reflected by the nth bottom surface, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 159682DEST_PATH_IMAGE001
according to the trigonometric function law, the transformation is as follows:
Figure 538711DEST_PATH_IMAGE002
Figure 729521DEST_PATH_IMAGE003
。
the thickness measurement formula can measure the accurate propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of knowing the accurate thickness H of the workpiece material:
Figure 219408DEST_PATH_IMAGE004
。
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the critical refraction longitudinal wave generated on the surface of the ultrasonic incident material and the multiple reflection of the bottom surface back to the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
The module for processing ultrasonic signals by ultrasonic measurement stress comprises: determining a difference value delta T0 between the critical refraction longitudinal wave in the stress-free calibration process and the T0 corresponding to the critical refraction longitudinal wave in the stress test process, and substituting the delta T0 into an ultrasonic stress formula:
Figure 546484DEST_PATH_IMAGE005
and calculating stress values, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
A module for processing an ultrasound signal to determine the time of arrival of a critically refracted longitudinal wave or a bottom-emitting surface wave, comprising: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control module to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control module adopts at least one movable horizontal vernier or a peak value proportion gate as a threshold value, and when the peak intensity in the waveform data section is greater than the gate threshold value, the corresponding time of the waveform coming is considered; fig. 5 is a schematic diagram showing a method for selecting a waveform data segment by a vertical cursor and determining the waveform arrival time by a horizontal cursor, and fig. 6 is a schematic diagram showing a method for selecting a waveform data segment by a frame and determining the waveform arrival time by a horizontal cursor.
For example, during testing, the module adopts two pairs of movable vertical vernier lines, a waveform data segment where critical refraction longitudinal waves are located is selected from a first group of vernier lines, a surface wave data segment reflected by a 1 st bottom surface is selected from a second group of vernier lines, ultrasonic waves experience a V-shaped process in a workpiece material, at the moment, n =1, a peak value proportion gate is adopted to respectively determine the time T0 and T1 when LCR waves selected from the first group of vernier lines and surface wave RSW1 waveforms emitted by the bottom surface selected from the second group of vernier lines arrive at corresponding time, and the waveforms are substituted into an ultrasonic thickness measuring module
Figure 361993DEST_PATH_IMAGE008
H is calculated; if the surface wave data segment reflected by the second bottom surface is selected by the second group of cursors, the ultrasonic wave undergoes two V-shaped histories in the workpiece material, at the moment, n =2, and the ultrasonic wave is substituted into the ultrasonic thickness measuring module
Figure 40099DEST_PATH_IMAGE009
H is calculated; when in testing, a first group of LCR waves are temporarily corresponding to T0 and an LCR wave is temporarily corresponding to T0 when in stress-free calibration, and the difference value delta T0 is substituted into an ultrasonic stress module:
Figure 333678DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
The module can be used for independently measuring the thickness of the workpiece material, can be used for respectively measuring the stress and the thickness of the material without changing the receiving and transmitting mode of the ultrasonic probe, and can also be used for simultaneously measuring the stress and the thickness of the material without changing the receiving and transmitting mode of the ultrasonic probe.
The accuracy of stress and thickness measurement can be further improved in an averaging mode through repeated acquisition, wherein the repeated acquisition comprises repeated acquisition of ultrasonic signals for averaging and then stress and thickness measurement, and also comprises repeated measurement of stress and thickness and then averaging.
The ultrasonic probe transceiving mode is not changed, and the mode of probe transceiving and position maintaining which keeps the ultrasonic thickness measurement and the ultrasonic stress the same is adopted.
The processing module determines a time difference delta T0 corresponding to the time when the LCR wave arrives at the unstressed calibration time in the test, the LCR wave at the unstressed calibration time and the LCR wave at the test can be arranged in the same graph, a horizontally moving cursor is used as a valve threshold, when the waveform value exceeds the threshold range, the time when the LCR wave arrives is considered, and the difference between the two waveforms is the delta T0.
Further implementation examples are that thickness measurement and stress measurement are carried out simultaneously, an ultrasonic receiving and transmitting probe adopts 10MHZ, the angle of the inclined plane of a connecting piece is kept at 28 degrees with the bottom surface, a 2.7GHz acquisition board card is adopted to acquire ultrasonic signals, the time T0 and the time T1 when LCR waves and RSW1 waves of the acquired ultrasonic signals come are respectively determined, V is the longitudinal wave propagation speed of the ultrasonic waves in the steel, and the longitudinal wave propagation speed is substituted into the thickness measurement formula to calculate the material thickness; and simultaneously determining the difference value delta T0 between the T0 value during the test and the T0 value during the stress-free calibration and the calibrated K sound time difference coefficient value, and substituting the difference value delta T0 and the calibrated K sound time difference coefficient value into the ultrasonic stress formula to calculate the stress value.
In a further implementation example, a workpiece with standard thickness is used for calibrating the ultrasonic propagation speed, an ultrasonic transceiving probe in a transceiving ultrasonic probe module mode is 10MHZ, the angle of the inclined plane of a connecting piece is kept 28 degrees with the bottom surface, a 2.7GHz acquisition board card is used for acquiring ultrasonic signals, the time T1-T0 of LCR waves and RSW1 waves of the acquired ultrasonic signals is determined, and the time T1-T0 is substituted into a sound velocity measurement formula converted by the thickness measurement formula to calculate the longitudinal wave propagation speed of the ultrasonic waves in the workpiece material.
When the form of a one-shot double-receiving ultrasonic probe module is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface, a vertical inclined plane is provided with a threaded hole for mounting an ultrasonic transmitting probe and an ultrasonic receiving probe, one side of the ultrasonic receiving probe is additionally provided with an inclined plane forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded hole for mounting a second ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probes are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; the ultrasonic wave transmitting module transmits a pulse waveform, and ultrasonic waves are generated by the ultrasonic transmitting probe after excitation; the generated ultrasonic waves are emitted to the surface of the material from the organic glass, and the Snell law is met; the ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, the ultrasonic echo signals transmitted along the surface of the material are sequentially received by two ultrasonic receiving probes with the same angle respectively, and the ultrasonic signals are collected through two connected channel ultrasonic collection modules; the difference between the two is that the ultrasonic wave signal of the first channel connected with the first ultrasonic receiving probe receives surface wave signals generated by critical refraction longitudinal waves and a plurality of subsequent bottom surface reflected waves in advance, and the surface wave signals generated by critical refraction longitudinal waves and a plurality of subsequent bottom surface reflected waves are later than the first channel time after the second channel connected with the second ultrasonic receiving probe receives the ultrasonic wave signals. Fig. 2 is a schematic view showing the connection between an ultrasonic transmitting probe and an ultrasonic receiving probe in a one-shot and two-shot mode.
Determining the corresponding time of critical refracted longitudinal waves and surface wave signals reflected by the bottom surface in ultrasonic signals received by any one of two channels in an ultrasonic signal processing module, and determining and selecting waveform data segments of the critical refracted longitudinal waves to be analyzed simultaneously and at least one surface waveform reflected by the bottom surface by adopting movable vertical graticules, square frames, or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control module to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control module includes a time deemed to be temporally corresponding to the incoming waveform when the peak intensity in the waveform data segment is greater than the gate threshold using at least one movable horizontal cursor or a peak-scale gate as the threshold.
One-transmitting and two-receiving ultrasonic probe moduleDetermining the temporary time T0 from the critical refraction longitudinal wave signal and the temporary time Tn from the surface wave signal emitted by the nth bottom surface in the form, and substituting the T0 and the Tn into an ultrasonic thickness measuring module:
Figure 780839DEST_PATH_IMAGE001
according to the trigonometric function law, the transformation is as follows:
Figure 236091DEST_PATH_IMAGE002
Figure 401494DEST_PATH_IMAGE003
。
the thickness measuring module can measure the accurate propagation speed of ultrasonic waves in a medium in a variable manner under the condition of knowing the accurate thickness H of a workpiece material:
Figure 233183DEST_PATH_IMAGE004
。
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the critical refraction longitudinal wave generated on the surface of the ultrasonic wave incident material and the multiple reflection of the bottom surface back to the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
The ultrasonic signal module for ultrasonic measurement stress processing for one-transmission and two-reception detection further comprises: determining a difference value between a critical refraction longitudinal wave in an ultrasonic signal of the second ultrasonic receiving probe and a critical refraction longitudinal wave in an ultrasonic signal of the first ultrasonic receiving probe during stress-free calibration as a calibration initial value T0; determining a difference value between a critical refraction longitudinal wave in the ultrasonic signal of the second ultrasonic receiving probe and a critical refraction longitudinal wave in the ultrasonic signal of the first ultrasonic probe during stress test as a test value T0; the difference value delta T0 between a test value T0 corresponding to the critical refraction longitudinal wave and a calibration initial value T0 during one-shot and two-shot stress measurement is substituted into an ultrasonic stress formula:
Figure 800431DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
The thickness of the workpiece material can be measured independently through the module, the stress and the thickness of the material can be measured respectively under the condition that the receiving and sending modes of the ultrasonic probe are not changed, and the stress and the thickness of the material can be measured simultaneously under the condition that the receiving and sending modes of the ultrasonic probe are not changed; the accuracy of stress and thickness measurement can be further improved in an averaging mode through repeated acquisition, wherein the repeated acquisition comprises repeated acquisition of ultrasonic signals for averaging and then stress and thickness measurement, and also comprises repeated measurement of stress and thickness and then averaging.
The mode of not changing the transceiving of the ultrasonic probe module refers to a mode of maintaining the transceiving of the probe and the position maintaining of the ultrasonic thickness measurement and the ultrasonic stress.
The determining a difference Δ T0 between a test value T0 corresponding to the critical refracted longitudinal wave and a calibration initial value T0 when the one-transmitter-two-receiver ultrasonic probe module measures the stress includes: placing the ultrasonic signal of the first channel and the ultrasonic signal of the second channel in the same graph or placing the ultrasonic signals in the two graphs for display respectively when no stress is calibrated, using one or two horizontally moving cursors as a valve threshold, and respectively determining the time when the LCR wave comes when the waveform value of the critical refraction longitudinal wave exceeds the threshold range, wherein the difference value of the two waveforms is a calibration initial value T0; during testing, the ultrasonic signal of the first channel and the ultrasonic signal of the second channel are placed in the same graph or are placed in two graphs to be displayed respectively, one or two horizontally moving cursors are used as valve thresholds, the time when the LCR wave comes is determined when the waveform value of the critical refraction longitudinal wave exceeds the threshold range, and the difference value of the two waveforms is the test value T0.
Further, the thickness measurement and the stress measurement are carried out simultaneously by adopting a thickness measurement module, an ultrasonic receiving and transmitting probe adopts 5MHZ, the angle of the inclined plane of a connecting piece is kept to be 25 degrees with the bottom surface, a 2GHz acquisition board card is adopted to acquire ultrasonic signals, the time T2-T0 of LCR wave and RSW2 wave of the ultrasonic signals acquired by one channel is determined, n is 2, V is the longitudinal wave propagation speed of the ultrasonic in steel, and the longitudinal wave propagation speed is substituted into the thickness measurement formula to calculateThe thickness of the material is obtained; a difference value delta T0 between a test value T0 of a difference value between critical refracted longitudinal waves of two channel ultrasonic signals during one-shot double-shot stress measurement and an initial value T0 of a difference value between critical refracted longitudinal waves of two channel ultrasonic signals during calibration (the test value T0-the initial value T0) is substituted into an ultrasonic stress formula:
Figure 426584DEST_PATH_IMAGE005
and calculating a stress value, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences.
In a further implementation example, a workpiece with a standard thickness is used for calibrating the ultrasonic propagation speed, an ultrasonic transceiving probe in a transceiving mode is 5MHZ, the angle of the inclined plane of a connecting piece is kept 25 degrees with the bottom surface, a 2GHz acquisition board card is used for acquiring ultrasonic signals, the time T2-T0 of LCR waves and RSW2 waves of the acquired ultrasonic signals is determined, n =2 is taken and substituted into a sound velocity measurement formula converted by the thickness measurement formula, and the accurate longitudinal wave propagation speed of the ultrasonic in the workpiece material is obtained.
Meanwhile, the embodiment also discloses a completely different ultrasonic thickness measuring method relative to the ultrasonic thickness measuring method carried out on the surface of a single ultrasonic probe which is integrated with the receiving and transmitting and vertically incident material.
The invention provides a brand-new method for measuring the thickness of a material by using a pitch-catch oblique incidence, which comprises the following steps: fixing an ultrasonic transmitting probe and an ultrasonic receiving probe on a connecting piece at a specific angle in a manner of transmitting and receiving; the ultrasonic transmitting probe generates ultrasonic waves which are obliquely incident to the surface of the material, and the ultrasonic receiving probe receives ultrasonic signals; the ultrasonic signal is processed to measure the thickness of the material.
The ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle of ultrasonic waves is not more than a first critical angle, and the incident angle is as follows: 0< theta <45 deg..
When the mode of one-sending and one-receiving is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded hole for installing an ultrasonic transmitting probe and an ultrasonic receiving probe, the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; the ultrasonic wave transmitting circuit transmits a pulse waveform, and an ultrasonic wave is generated by the ultrasonic transmitting probe after excitation; the generated ultrasonic waves are incident to the surface of the material from the organic glass, and the Snell law is met; ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflections are generated between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, ultrasonic echo signals transmitted along the surface of the material are sequentially received by ultrasonic receiving probes with the same angle, and the ultrasonic signals are acquired through an ultrasonic acquisition module; fig. 3 is a schematic diagram illustrating the path of an ultrasonic signal in a material in a pitch-catch mode.
The method for processing ultrasonic signals comprises the following steps: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal reflected by the nth bottom surface, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 344862DEST_PATH_IMAGE001
according to the trigonometric function law, the transformation is as follows:
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。
the thickness measuring formula can measure the accurate propagation speed of the ultrasonic wave in the medium in a variable way under the condition of knowing the accurate thickness H of the workpiece material:
Figure 199051DEST_PATH_IMAGE004
。
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the critical refraction longitudinal wave generated on the surface of the ultrasonic incident material and the multiple reflection of the bottom surface back to the upper surface; in the formula, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
The method for processing the ultrasonic signals to determine the coming time of the critical refraction longitudinal wave or the surface wave reflected by the bottom surface comprises the following steps: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control method to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control method comprises the steps that at least one movable horizontal vernier or a peak value proportion gate is used as a threshold value, and when the peak intensity in a waveform data section is larger than the gate threshold value, the corresponding time of a waveform comes temporarily is considered; as shown in fig. 5 and 6.
During testing, two groups of movable frames are adopted, a waveform data segment where critical refraction longitudinal waves are located is selected in the first group of movable frames, a surface wave data segment reflected by the 1 st bottom surface is selected in the second group of movable frames, ultrasonic waves experience a V-shaped process in a workpiece material, at the moment, n =1, a movable cursor or a peak value proportion gate is adopted to respectively determine the time T0 and T1 when LCR waves selected in the first group of movable frames and surface wave RSW1 waveforms emitted from the bottom surface selected in the second group of movable frames come, and the waveforms are substituted into an ultrasonic thickness measuring formula
Figure 73466DEST_PATH_IMAGE008
H is calculated; if the second group of boxes selects the surface wave data segment reflected by the second bottom surface, the ultrasonic wave undergoes two 'V' -shaped processes in the workpiece material, and n =2 at this time, and the two processes are substituted into the ultrasonic thickness measurement formula
Figure 512538DEST_PATH_IMAGE009
H is determined.
The accuracy of thickness measurement can be further improved in an averaging mode through repeated acquisition, wherein the repeated acquisition comprises repeated acquisition of ultrasonic signals for averaging and then thickness measurement, and also comprises repeated measurement for averaging after the thickness is repeatedly measured for multiple times.
In a further implementation example, thickness measurement is performed, an ultrasonic receiving and transmitting probe adopts 5MHZ, the angle of the inclined plane of a connecting piece is kept 23 degrees with the bottom surface, a 1GHz acquisition board card is adopted to acquire ultrasonic signals, the time T0 and the time T1 of the arrival of LCR waves and RSW1 waves of the acquired ultrasonic signals are respectively determined, and V is the longitudinal wave propagation speed of the ultrasonic waves in the steel and is substituted into the thickness measurement formula to calculate the material thickness.
In a further implementation example, a workpiece with standard thickness is used for calibrating the ultrasonic propagation speed, the ultrasonic transceiving probe in a transceiving mode adopts 5MHZ, the angle of the inclined plane of the connecting piece is kept 23 degrees with the bottom surface, a 1GHz acquisition board card is used for acquiring ultrasonic signals, the time T1-T0 of LCR waves and RSW1 waves of the acquired ultrasonic signals is determined, and the time T1-T0 is substituted into a sound velocity measurement formula converted by the thickness measurement formula to calculate the longitudinal wave propagation speed of the ultrasonic in the workpiece material.
In order to achieve the above object, the present embodiment further discloses an ultrasonic thickness measuring device which is completely different from the ultrasonic thickness measuring device for a single ultrasonic probe integrated with a transceiver and vertically incident on the surface of the material.
The invention provides a brand new device for measuring the thickness of a material by transmitting and receiving oblique incidence, which comprises: a screen; the ultrasonic probe module fixes the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-transmitting-one-receiving or one-transmitting-two-receiving mode; the ultrasonic transmitting module is used for connecting the ultrasonic transmitting probe to generate ultrasonic waves to obliquely enter the surface of the material; the ultrasonic receiving module is used for connecting the ultrasonic receiving probe to receive the ultrasonic signals; and the signal processing module is used for processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the receiving and transmitting modes of the ultrasonic probe.
The ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle of ultrasonic waves is not more than a first critical angle, and the incident angle is as follows: 0< theta <45 deg..
When the mode of the one-shot ultrasonic probe module is implemented, the connecting piece comprises two symmetrical inclined planes forming an angle theta with the bottom surface, the vertical inclined plane is provided with a threaded hole for installing the ultrasonic emission probe and the ultrasonic receiving probe, the ultrasonic emission probe and the ultrasonic receiving probe are respectively fixed on the connecting piece, and the connecting piece is also provided with a magnet which is fixed or adsorbed on the surface of a workpiece material after being coated with a coupling agent; the ultrasonic wave transmitting module transmits a pulse waveform, and ultrasonic waves are generated by the ultrasonic transmitting probe after excitation; the generated ultrasonic waves are emitted to the surface of the material from the organic glass, and the Snell law is met; ultrasonic waves are incident to the surface of a workpiece with the thickness of H at an oblique incidence angle theta, critical refraction longitudinal waves (LCR) are generated and then are transmitted to the bottom of a medium, multiple reflection occurs between the bottom surface and the upper surface, surface wave signals (RSW 1, RSW2 and RSW 3) are generated when the ultrasonic waves are reflected to the upper surface each time, the ultrasonic echo signals transmitted along the surface of the material are sequentially received by ultrasonic receiving probes with the same angle, and the ultrasonic signals are acquired through an ultrasonic acquisition module connected with the ultrasonic receiving probes; fig. 3 is a schematic diagram showing the path of an ultrasonic signal in a pitch-catch mode in a material.
The ultrasonic signal processing module in the ultrasonic thickness measuring device in the form of the one-transmitting-one-receiving oblique incidence ultrasonic probe module comprises the following functions: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal reflected by the nth bottom surface, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
Figure 788799DEST_PATH_IMAGE001
according to the trigonometric function law, the transformation is as follows:
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Figure 649624DEST_PATH_IMAGE003
。
the thickness measuring module can measure the precise propagation speed of the ultrasonic wave in the medium in a variable way under the condition of knowing the accurate thickness H of the workpiece material:
Figure 626807DEST_PATH_IMAGE004
。
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the propagation speed of the ultrasonic wave, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the critical refraction longitudinal wave generated on the surface of the ultrasonic wave incident material and the multiple reflection of the bottom surface back to the upper surface; in the module, tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
The module for processing the ultrasonic signal module to determine the coming time of the critical refracted longitudinal wave or the surface wave emitted from the bottom surface comprises: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control module to determine the coming time of waveforms corresponding to critical refraction longitudinal waves and surface waves; the gate control module adopts at least one movable horizontal vernier or a peak value proportion gate as a threshold value, and when the peak intensity in the waveform data section is greater than the gate threshold value, the corresponding time of the waveform coming is considered; as shown in fig. 5 and 6.
For example, during testing, the module adopts two pairs of movable vertical vernier lines, a waveform data segment where critical refraction longitudinal waves are located is selected from a first group of vernier lines, a surface wave data segment reflected by a 1 st bottom surface is selected from a second group of vernier lines, ultrasonic waves experience a V-shaped process in a workpiece material, at the moment, n =1, a peak value proportion gate is adopted to respectively determine the time T0 and T1 when LCR waves selected from the first group of vernier lines and surface wave RSW1 waveforms emitted by the bottom surface selected from the second group of vernier lines arrive at corresponding time, and the waveforms are substituted into an ultrasonic thickness measuring module
Figure 757574DEST_PATH_IMAGE008
H is calculated; if the surface wave data segment reflected by the second bottom surface is selected by the second group of cursors, the ultrasonic wave undergoes two V-shaped histories in the workpiece material, at the moment, n =2, and the ultrasonic wave is substituted into the ultrasonic thickness measuring module
Figure 164941DEST_PATH_IMAGE009
H is determined.
The accuracy of thickness measurement can be further improved in an averaging mode through repeated acquisition, wherein the repeated acquisition comprises repeated acquisition of ultrasonic signals for averaging and then thickness measurement, and also comprises repeated measurement for averaging after the thickness is repeatedly measured for multiple times.
In a further embodiment, ultrasonic thickness measurement is performed, an ultrasonic receiving and transmitting probe adopts 5MHZ, the angle of the inclined plane of a connecting piece is kept at 20 degrees with the bottom surface, a 1GHz acquisition board card is adopted to acquire ultrasonic signals, the time T0 and the time T3 when LCR waves and RSW3 waves of the acquired ultrasonic signals come are respectively determined, n =3, V is the longitudinal wave propagation speed of ultrasonic waves in steel, and the longitudinal wave propagation speed is substituted into the thickness measurement formula to calculate the material thickness.
In a further implementation example, a workpiece with a standard thickness is used for calibrating the ultrasonic propagation speed, an ultrasonic transceiving probe in a transceiving ultrasonic probe module mode is 5MHZ, the angle of the inclined plane of a connecting piece is kept 20 degrees with the bottom surface, a 1GHz acquisition board card is used for acquiring ultrasonic signals, the time T1-T0 and n =3 of LCR waves and RSW3 waves of the acquired ultrasonic signals are determined, and the time is substituted into a sound velocity measurement formula converted by the thickness measurement formula to calculate the longitudinal wave propagation speed of the ultrasonic waves in the workpiece material.
It should be noted that, for simplicity of description, the above-mentioned method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present invention is not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the invention. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required by the invention.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one type of logical functional division, and other divisions may be realized in practice, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed coupling or direct coupling or communication connection between each other may be through some interfaces, indirect coupling or communication connection between devices or units, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a mobile terminal, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic disk, or an optical disk, and various media capable of storing program codes.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (13)

1. An ultrasonic nondestructive testing method for simultaneously carrying out high-precision stress and thickness measurement is characterized by comprising the following steps:
fixing the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-pitch and one-pitch or one-pitch and double-pitch mode;
the ultrasonic transmitting probe generates ultrasonic waves which are obliquely incident on the surface of the material, and the ultrasonic receiving probe receives ultrasonic signals;
and processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the transceiving mode of the ultrasonic probe.
2. The method of ultrasonic non-destructive testing for simultaneous high precision stress and thickness measurements according to claim 1, wherein said method of ultrasonic thickness measurement processing ultrasonic signals comprises: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal reflected by the nth bottom surface,
substituting T0 and Tn into an ultrasonic thickness measurement formula:
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；
the method for processing the ultrasonic signal by ultrasonic measurement stress comprises the following steps: determining the difference value delta T0= T0 '-T0 between T0' corresponding to the critical refraction longitudinal wave in the stress-free calibration process and T0 corresponding to the critical refraction longitudinal wave in the stress test process, and substituting the delta T0 into an ultrasonic stress formula:
Figure 715660DEST_PATH_IMAGE002
calculating stress values, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences;
the thickness measurement formula can measure the precise propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of knowing the accurate thickness H of the workpiece material:
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；
wherein, the ultrasonic thickness measuring formula can be transformed into:
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；
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the ultrasonic wave propagation speed, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the selected ultrasonic wave after being incident on the material and reflected back to the upper surface for the nth time of the bottom surface; wherein Tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
3. The ultrasonic non-destructive inspection method for simultaneously making high precision stress and thickness measurements according to claim 1, wherein: the ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle theta of ultrasonic waves is not more than a first critical angle;
the method for processing ultrasonic signals comprises the steps of determining the coming time of critical refraction longitudinal waves and/or surface waves reflected by a bottom surface in the ultrasonic signals: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control method to determine the coming time of waveforms corresponding to critical refraction longitudinal waves and surface waves; the gate control method comprises the steps that at least one movable horizontal vernier or a peak value proportion gate is used as a threshold value, and when the peak intensity in a waveform data segment is larger than the gate threshold value, the time corresponding to the coming of a waveform is considered;
the simultaneous measurement of the stress and the material thickness under the condition of not changing the receiving and transmitting modes of the ultrasonic probe comprises the steps of simultaneously measuring the stress and the thickness by acquiring ultrasonic signals once (or repeatedly averaging), and respectively measuring the stress and the thickness by acquiring the ultrasonic signals once (or repeatedly averaging);
the unchanged ultrasonic probe transceiving mode refers to a probe transceiving mode which keeps the ultrasonic thickness measurement and the ultrasonic stress the same.
4. A method for measuring the thickness of a material by ultrasonic oblique incidence transceiving is characterized by comprising the following steps:
fixing an ultrasonic transmitting probe and an ultrasonic receiving probe on a connecting piece at a specific angle in a form of transmitting and receiving;
the ultrasonic transmitting probe generates ultrasonic waves which are obliquely incident to the surface of the material, and the ultrasonic receiving probe receives ultrasonic signals;
and processing the ultrasonic signals to measure the thickness of the material.
5. The method for ultrasonic oblique-incidence transreceiver measurement of material thickness of claim 4, wherein:
the method for processing ultrasonic signals by measuring thickness comprises the following steps: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal emitted from the nth bottom surface, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula to obtain the thickness:
Figure 166921DEST_PATH_IMAGE001
(ii) a The ultrasonic thickness measurement formula can be transformed into:
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；
the thickness measurement formula can measure the precise propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of the known accurate thickness H of the workpiece material:
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；
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the ultrasonic wave propagation speed, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the selected ultrasonic wave after being incident on the material and reflected back to the upper surface for the nth time of the bottom surface; wherein Tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
6. The method for ultrasonic oblique-incidence transreceiver measurement of material thickness of claim 4, wherein:
the ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle of ultrasonic waves is not more than a first critical angle;
the method of processing an ultrasound signal comprises determining a critically refracted longitudinal wave or a bottom-launched surface wave: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected simultaneously by adopting a movable vertical vernier line, a square frame or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control method to determine the coming time of waveforms corresponding to critical refraction longitudinal waves and surface waves; the gate control method comprises the step of adopting at least one movable horizontal cursor or a peak value proportion gate as a threshold value, and considering the time corresponding to the time when the waveform comes when the peak intensity in the waveform data segment is greater than the gate threshold value.
7. An ultrasonic nondestructive testing device for simultaneously performing high-precision stress and thickness measurement, characterized by comprising:
a screen;
the ultrasonic probe module fixes the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-transmitting-one-receiving or one-transmitting-two-receiving mode;
the ultrasonic transmitting module is used for connecting the ultrasonic transmitting probe to generate ultrasonic waves to obliquely enter the surface of the material;
the ultrasonic receiving module is used for connecting the ultrasonic receiving probe to receive the ultrasonic signals;
and the signal processing module is used for processing the ultrasonic signals and simultaneously measuring the stress and the material thickness under the condition of not changing the receiving and transmitting mode of the ultrasonic probe.
8. The apparatus for simultaneous high precision stress and thickness ultrasonic non-destructive testing according to claim 7, wherein: the ultrasonic thickness measurement signal processing module comprises the following functions: determining the temporary time T0 of the critical refraction longitudinal wave signal and the temporary time Tn of the surface wave signal emitted from the nth bottom surface, and substituting the T0 and the Tn into an ultrasonic thickness measurement formula:
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；
the ultrasonic measurement stress signal processing module comprises the following functions: determining the difference value delta T0 between the critical refraction longitudinal wave in the stress-free calibration process and the T0 corresponding to the critical refraction longitudinal wave in the stress test process, and substituting the delta T0 into an ultrasonic stress formula:
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calculating stress values, wherein K is an acoustic time difference coefficient and can be obtained by calibrating slopes corresponding to different stresses and acoustic time differences; the ultrasonic thickness measurement formula can be transformed into:
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Figure 185190DEST_PATH_IMAGE005
；
the thickness measurement formula can measure the precise propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of the known accurate thickness H of the workpiece material:
Figure 880614DEST_PATH_IMAGE003
；
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the ultrasonic wave propagation speed, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the selected ultrasonic wave after being incident on the material and reflected back to the upper surface for the nth time of the bottom surface; wherein Tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
9. The apparatus for simultaneous high precision stress and thickness measurement according to claim 7, wherein: the ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle of ultrasonic waves is not more than a first critical angle;
the processing ultrasound module comprises a module for determining the arrival time of a critically refracted longitudinal wave and/or a bottom surface reflected surface wave in the ultrasound signal: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected by adopting a movable vertical vernier line, a square frame, or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control module to determine the coming time of waveforms corresponding to critical refraction longitudinal waves and surface waves; the gate control module adopts at least one movable horizontal vernier or a peak value proportion gate as a threshold value, and considers the time corresponding to the arrival of the waveform when the peak intensity in the waveform data section is greater than the gate threshold value;
the simultaneous measurement of the stress and the material thickness under the condition of not changing the receiving and transmitting modes of the ultrasonic probe comprises the simultaneous measurement of the stress and the thickness by acquiring the ultrasonic signals once (or repeatedly averaging), and also comprises the single measurement of the stress and the thickness by acquiring the ultrasonic signals once (or repeatedly averaging);
the unchanged ultrasonic probe transceiving mode refers to a probe transceiving mode which keeps the ultrasonic thickness measurement and the ultrasonic stress the same.
10. An apparatus for ultrasonic oblique incidence transceive thickness measurement of a material, comprising:
a screen;
the ultrasonic probe module fixes the ultrasonic transmitting probe and the ultrasonic receiving probe on the connecting piece at a specific angle in a one-transmitting-one-receiving mode;
the ultrasonic transmitting module is used for connecting the ultrasonic transmitting probe to generate ultrasonic waves to obliquely enter the surface of the material;
the ultrasonic receiving module is used for connecting the ultrasonic receiving probe to receive the ultrasonic signals;
and the signal processing module is used for processing the ultrasonic signals to measure the thickness of the material.
11. The apparatus for ultrasonic oblique-incidence transreceiver measurement of material thickness of claim 10, wherein:
the ultrasonic measurement thickness signal processing module comprises: determining the temporary time T0 from the critical refraction longitudinal wave signal and the temporary time Tn from the surface wave signal emitted from the nth bottom surface, and substituting the time T0 and the time Tn into an ultrasonic thickness measurement formula to obtain the thickness:
Figure 325502DEST_PATH_IMAGE001
(ii) a Wherein, the ultrasonic thickness measuring formula can be transformed into:
Figure 866204DEST_PATH_IMAGE004
Figure 211473DEST_PATH_IMAGE005
(ii) a The thickness measurement formula can measure the precise propagation speed of the ultrasonic wave in the medium in a variable manner under the condition of the known accurate thickness H of the workpiece material:
Figure 812218DEST_PATH_IMAGE003
；
h is the thickness of a workpiece material, and theta is the oblique incident angle of the ultrasonic wave; v is the ultrasonic wave propagation speed, n (n =1,2,3, 4.) is the serial number of the surface wave generated by the selected ultrasonic wave after being incident on the material and reflected back to the upper surface for the nth time of the bottom surface; wherein Tn-T0 can be accurate to nanosecond level, so H thickness measurement can also be accurate to nanometer level.
12. The apparatus for ultrasonic oblique-incidence transreceiver measurement of material thickness of claim 10, wherein:
the ultrasonic transmitting probe and the ultrasonic receiving probe are fixed on the connecting piece at a specific angle, so that the angle between the ultrasonic transmitting probe and the surface of the material is theta, and the oblique incident angle of ultrasonic waves is not more than a first critical angle;
the processing ultrasound module comprises a module for determining the arrival time of critical refracted longitudinal waves and/or bottom surface reflected surface waves in the ultrasound signal: determining waveform data segments where critical refraction longitudinal waves to be analyzed and at least one bottom surface reflected surface waveform are selected by adopting a movable vertical vernier line, a square frame, or numerical input or mouse frame selection; analyzing the waveform data segment by adopting a gate control module to determine the waveform coming time corresponding to the critical refraction longitudinal wave and the surface wave; the gate control module comprises at least one movable horizontal vernier or a peak value proportion gate which is used as a threshold value, and when the peak intensity in the waveform data section is larger than the gate threshold value, the corresponding time of the waveform is considered to come.
13. A formula for measuring the thickness of a material by ultrasonic oblique incidence under a pitch-catch mode is characterized in that:
Figure 744402DEST_PATH_IMAGE001
(ii) a In the formula, θ is an oblique incident angle of the ultrasonic wave, V is an ultrasonic wave propagation speed, T0 is a temporal time of a critical refracted longitudinal wave signal, tn is a temporal time of a surface wave signal emitted from an nth bottom surface, and n (n =1,2,3, 4.) is a surface wave serial number generated by measuring an incident material of the selected ultrasonic wave and reflecting the nth time of the bottom surface back to the upper surface, wherein Tn-T0 can be accurate to a nanosecond level, so that H thickness measurement can be accurate to a nanometer level; the equation can be transformed according to trigonometric function rules:
Figure 88796DEST_PATH_IMAGE004
Figure 790036DEST_PATH_IMAGE005
。
CN202211340887.XA 2022-10-30 2022-10-30 Ultrasonic detection method and device for simultaneously measuring high-precision stress and thickness Pending CN115561316A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117804653A (en) * 2023-12-28 2024-04-02 深圳职业技术大学 Residual stress detection device and method based on critical refraction longitudinal wave

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117804653A (en) * 2023-12-28 2024-04-02 深圳职业技术大学 Residual stress detection device and method based on critical refraction longitudinal wave

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