WO2017219468A1

WO2017219468A1 - Ultrasonic detection method for crack propagation in ship body of unmanned ship

Info

Publication number: WO2017219468A1
Application number: PCT/CN2016/095095
Authority: WO
Inventors: 杨越
Original assignee: 杨越
Priority date: 2016-06-22
Filing date: 2016-08-14
Publication date: 2017-12-28
Also published as: CN106153722A

Abstract

Disclosed is an ultrasonic detection method for crack propagation in a ship body of an unmanned ship. The method comprises: establishing a probe array (101), sending an ultrasonic wave into a sample (100), and setting a transceiver (102) and a display system (103) to display a received signal; placing the probe array (101) nearby a crack detection surface of the sample (100), and generating an ultrasonic wave in response to a drive signal provided by the transceiver (102), wherein the transceiver (102) comprises a computer (102A), a time-prolonging controller (102B), a pulser (102C), a receiver (102D) and a data collection system (102E); sending the drive signal from the pulser (102C) to the probe array (101), and the receiver (102D) correspondingly processing a receiving signal output by the probe array (101), wherein the computer (102A) controls the time-prolonging controller (102B), the pulser (102C), the receiver (102D) and the data collection system (102E), so that an element operates normally; and the data collection system (102E) processing the receiving signal from the receiver (102D), and sending a processing result to the display system (103).

Description

Ultrasonic detection method for crack propagation in unmanned ship hull

Technical field

The invention relates to the detection of crack propagation in the hull of an unmanned ship, and particularly relates to the method for detecting the crack propagation of the unmanned ship hull by using ultrasonic method and the corresponding ultrasonic crack propagation detector.

Background technique

Drones and driverless cars are in the tech world, and the limelight is exhausted. In contrast, low-profile unmanned ships are less well-known. In the novel, the unmanned ship has always shrouded a mysterious atmosphere. The famous "ghost ship" is the classic material of the writer's fictional nautical story. In reality, the unmanned ship is the treasure of the military field of all countries and is the important competition of science and technology. technology. At present, the unmanned ship is in a period of rapid development. However, the unmanned ship still faces many technical bottlenecks before the launch of the launch and the operation on the water.

Unmanned ships, as the name implies, do not require human pilots to manipulate them. They have to face the harsh sea or other water conditions alone, so the sturdiness of the hull is very high, and the unmanned ship must crack the hull before launching the sea. Expand and carry out rigorous inspections, otherwise you will only be able to abandon unmanned ships in extreme weather and hydrological environments, and the economic losses are considerable.

Usually, the underwater detection of the unmanned hull is carried out by a diver or a remotely controlled diving vessel. In addition to visual inspection, closed-circuit television, magnetic powder and other technologies are used, but these tests are expensive and dangerous to the diver, and the detection effect largely depends on In seasonal and climatic conditions, conventional methods cannot be promptly investigated and immediately repaired and smiling during the early stages of fatigue failure, and the corrosion crack propagation of unmanned steel is often extended over time, so the present invention provides an ultrasonic The technical concept of form monitoring.

Summary of the invention

Therefore, an object of the present invention is to provide an ultrasonic detecting method for crack propagation in an unmanned ship hull, comprising the following steps:

(1) collecting a sample as a detection object, establishing an array of probes, transmitting ultrasonic waves into the sample, and setting a transceiver and a display system for displaying the received signals;

(2) placing the probe array on a defect detecting near surface of the sample and generating ultrasonic waves in response to a driving signal provided by the transceiver, the ultrasonic waves emitted by the probe array are transmitted through the sample, and the probe array detects the reflected wave;

(3) generating, according to the detected reflected wave echo, a corresponding received signal by the probe array, the received signal being input to the transceiver;

(4) The transceiver includes a computer, a delay controller, a pulser, a receiver, and a data acquisition system, and transmits a driving signal from the pulser to the probe array, and the corresponding receiver receives the received signal output by the probe array. , wherein the computer controls the delay controller, the pulser, the receiver, and the data acquisition system to enable the components to operate normally;

(5) The data acquisition system processes the received signal from the receiver and sends the processing result to the display system; wherein the process of processing the received signal after obtaining the echo as the defect indication is as follows:

(5-1) First, the normal angle defect detection technique is used to check the presence or absence of the indication, and the angle in the angled axial wave defect detection technique is set to about 45 degrees, or the position of the ultrasonic sensor or probe is adjusted to form The indication result of the angled longitudinal wave technique is displayed in the vicinity of the area A, where the range of the area A is defined as: multiplying the depth of the distal surface by 1/cos45 to obtain the propagation distance of the 45-degree echo, and simultaneously, multiple echoes The propagation time is approximately 1.5 times that of the corresponding distal surface;

(5-2) Then, it is checked whether the echo in the area B appears to determine whether the echo caused by the ID creep wave appears, wherein the range of the region B is defined as: the judgment of the presence or absence of the defect by using the ID creep wave, A probe array for angled axial wave defect detection is located at an angle of approximately 45 degrees;

(5-3) Finally, it is checked whether the echo in the region C appears to determine whether the echo caused by the mode-converted wave appears, wherein the region C range is defined as: using the waveform-converted wave to determine whether the defect exists, the angled longitudinal wave The probe array used for defect detection is assumed to be placed at a position of approximately 45 degrees;

(5-4) When any of the steps (5-1) to (5-3) finds a signal indicating that it is caused by a crack defect.

2. Preferably, the delay controller controls the time at which the pulser outputs the drive signal and controls the input time of the received signal from the receiver (102D), so that the operation of the probe array can be obtained according to the phased array technique.

Preferably, the number of echoes is directly obtained by the number of times of multi-bottom echo caused by the probe array for ultrasonic crack propagation detection or by measuring the number of times of multi-bottom echo using an additional probe capable of emitting ultrasonic waves in the vertical direction and using The number of measurements obtained is obtained or calculated by dividing the wall thickness by the axial/shear wave velocity in the case where the axial/shear wave velocity in the sample and the wall thickness of the sample are known.

Preferably, the probe array having the optimal cross-section busbar is used, that is, the transmission of the main beam of both the longitudinal wave and the shear wave and the reduction of the harsh sound protrusion are obtained, corresponding to the round-trip propagation time in the case of the sum of the wall thicknesses of the longitudinal waves and The received signal within the time range of the round-trip propagation time in the case of shear wave wall thickness is displayed on the screen.

Preferably, in the step (5-2), it is judged whether or not the echo caused by the total number of propagation of the OD creep wave from the corner crack surface is detected.

Another object of the present invention is to provide an ultrasonic crack propagation detector for performing an ultrasonic detecting method for crack propagation in an unmanned ship hull, comprising a probe array for transmitting ultrasonic waves into a sample, providing a driving signal with ultrasonic waves and receiving The probe array generates a corresponding transceiver for receiving signals and a display system for displaying the received signals; the transceiver includes a computer, a delay controller, a pulser, a receiver, and a data acquisition system to drive signals from the pulser Sended to the probe array, and the corresponding receiver receives the received signal output from the probe array, wherein the computer controls the delay controller, the pulser, the receiver, and the data acquisition system to enable the components to operate normally; the data acquisition system processes the reception The receiver receives the signal and sends the processing result to the display system.

Preferably, the probe array consists essentially of a plurality of ultrasonic sensor elements.

Preferably, the ultrasonic sensor element is a composite piezoelectric body comprising a PZT piezoelectric ceramic embedded in a polymeric material.

The above as well as other objects, advantages and features of the present invention will become apparent to those skilled in the <

DRAWINGS

Some specific embodiments of the present invention are described in detail below by way of example, and not limitation. In the drawing The same reference numbers indicate the same or similar parts or parts. Those skilled in the art should understand that the drawings are not necessarily drawn to scale. The objects and features of the present invention will become more apparent in consideration of the following description in conjunction with the accompanying drawings.

1 is a block diagram for explaining an unmanned ship hull ultrasonic crack propagation detecting method and an ultrasonic probe according to a first embodiment of the present invention.

Figure 2 is a block diagram showing an example of the composition of a probe (ultrasonic sensor) array used in the first embodiment of the present invention;

3A-3C are diagrams for explaining a longitudinal wave/shear wave main beam and a harsh sound protrusion generated by an ultrasonic sensor; wherein A: shear wave piercing sound protrusion; B: shear wave main beam; C: longitudinal wave The main beam, Figure 3A, 3B, 3C is drawn as follows: cell pitch: 1/2 wavelength; 1/3 wavelength and 1/4 wavelength,

The horizontal axis is: the incident angle (degrees) of the sample; the vertical axis is: the relevant amplitude;

Figure 4 is a schematic diagram for explaining an ID creep technique;

Figure 5 is a schematic diagram for explaining a waveform conversion technique;

Figure 6 is a table for explaining the longitudinal wave/shear wave velocity and the wave velocity in different solids;

Figure 7 is a schematic diagram for explaining an angle crack spread detection technique;

8A-8E are schematic block diagrams showing multi-reflection bottom echoes and display images in a sample;

Figure 9 is a schematic block diagram showing a display method used in the first embodiment of the present invention;

Figure 10 is a schematic diagram showing a display method used in the second embodiment of the present invention.

detailed description

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, a detailed description The sample shown by the box on each of the figures also represents the cross-section of the tubular sample along the axial direction and the sample of that cross-sectional shape.

Example 1

1 is a block diagram for explaining an ultrasonic crack propagation detecting method and an ultrasonic probe of an unmanned ship hull according to a first embodiment of the present invention. The embodiment shown in Figure 1 includes sample 100 as a detection object, probe array 101, transmitting ultrasonic waves into sample 100, transceiver 102, and display system 103 for displaying the received signals. In the first embodiment, an example of crack propagation detection for finding crack propagation (crack propagation) to the distal end surface of the sample 100 will be explained.

The probe array 101 is placed on a crack extension detecting surface (near surface) of the sample 100 and generates ultrasonic waves in response to a driving signal supplied from the transceiver 102. The ultrasonic waves emitted from the probe array 101 propagate through the sample 101, and the probe array 101 detects the reflected waves. The received signal generated by the probe array 101 in accordance with the detected reflected wave (echo) is input to the transceiver 102.

The transceiver 102 includes a computer 102A, a delay controller 102B, a pulser 102C, a receiver 102D, and a data acquisition system 102E. The drive signal from the pulser 102C is sent to the probe array 101, and the corresponding probe array 101 The output received signal is processed by the receiver 102D.

Computer 102A controls delay controller 102B, pulser 102C, receiver 102D, and data acquisition system 102E to cause the components to function properly.

The delay controller 102B controls the time at which the pulser 102C outputs the drive signal and controls the input time of the received signal from the receiver 102D, so that the operation of the probe array can be obtained according to the phased array technique.

Data acquisition system 102E processes the received signals from receiver 102D and sends the results to display system 103. The operation of display system 103 will be detailed below.

Next, the operation of the probe array 101 will be described in detail with reference to FIG. 2 is a schematic diagram showing most of the basic components of the probe array 101. As shown in FIG. 2, the probe array consists essentially of a plurality of ultrasonic sensor elements 201.

In this embodiment, a composite piezoelectric body (also referred to as a "composite") includes a PZT piezoelectric ceramic embedded in a polymeric material for use in an example of an ultrasonic sensor element 201. In this case, the parameters determining the performance of the probe array 101 include the cell pitch P.

The section bus bar P is a length obtained by adding the element width W of the ultrasonic sensor element 201 to the gap G between the two elements. The cell pitch P is a major factor determining the main beam generation and the harsh sound protrusion of the probe array 101.

As described in the background art, the conventional technique focuses on the generation of longitudinal waves, and thus the design of ultrasonic sensor elements for generating longitudinal waves is mainly focused on longitudinal waves generated by the overlapping of ultrasonic waves emitted from the elements. Therefore, in order to prevent the occurrence of a harsh sound protrusion with respect to the longitudinal wave (the ultrasonic wave does not propagate in the direction of the desired incident path), the cell pitch is usually set to 1/2 of the wavelength.

Here, the action of the cell pitch will be explained with reference to Figs. 3A, 3B and 3C. First, it is shown that an ultrasonic wave generated by a probe array including 24 elements including a longitudinal wave propagating in iron at an angle of 60 degrees is generated.

Figure 3A shows the main beam and the harsh sound protrusion obtained when the cell pitch in the conventional probe array is set to a wavelength of 1/2. Fig. 3B shows the case where the cell pitch length is reduced to 1/4 of the wavelength. Figure 3C shows the length (1/3 of the wavelength) used by the cell pitch proposed by the present invention.

As shown, the conventional cell pitch (1/2 wavelength) and the cell pitch (1/3 wavelength) of the present invention all produce a main beam (longitudinal wave) at a predetermined direction of 60 degrees.

However, if we focus on the shear wave generated simultaneously with the longitudinal wave, although the wave should only include the main beam propagating in the direction of approximately 29 degrees, the traditional cell pitch can still be seen in Figure 3A. Other shear waves (streaked sound protrusions) produced at approximately -40 degrees.

Meanwhile, in the case of using the cell pitch (1/3 wavelength) of the present invention in FIG. 3C, even if generated by the probe array The shear wave includes only the main beam, and it can be seen that the cross-section main beam of the present invention also satisfies the case of the shear wave.

In the case of Fig. 3B, the cell pitch length is further reduced from 1/3 wavelength because there are no harsh sound protrusions generated in both the longitudinal wave and the shear wave, and thus there is no particular problem. However, if we pay attention to the longitudinal wave, the half width position of the main beam propagating in the 60-degree direction (hereinafter referred to as "radiation elevation angle") in Fig. 3B becomes wider (approx. 20 degrees) than in Fig. 3C. . Due to the widening of the radiation elevation angle, the determination of the direction of the received signal (echo from the reflector) becomes difficult.

However, in order to use the probe array to implement the ID creep technique or the mode conversion technique to generate longitudinal ultrasonic waves and shear waves, it is necessary to make the generated longitudinal and shear waves contain only the main while maintaining the radiation elevation angle within a certain range. The beam so that the direction of the echo received by the reflector can be determined.

For the above reasons, the present invention uses a condition that a harsh sound protrusion is not generated in the shear wave angle range (shear angle of the shear wave) as a criterion for determining the cell pitch when the longitudinal wave propagates in the 90-degree direction.

Wherein "λ" represents the wavelength of the longitudinal wave in the sample, "ν" represents the wave velocity of the longitudinal wave in the sample, and "Vs" represents the wave velocity of the creep wave in the sample.

The ratio between the longitudinal wave velocity V and the creep wave velocity Vs in the solid (V/Vs: wave velocity ratio) is about 2 in many metal bodies as shown in FIG.

Therefore, summarizing the results of the formula (4), the present invention considers that the optimum cell pitch is about 1/3 of the wavelength of the longitudinal wave (from 1/4 wavelength to 1/2 wavelength).

For example, when the longitudinal wave velocity in the sample is 6000 m/s and the ultrasonic frequency used in this case is 2 MHz, a cell pitch of 1.0 mm can be selected as the optimum cell pitch of the embodiment of the present invention.

In this case, the cross-sectional width W = 0.9 mm and the gap G = 0.1 mm are used. For example, longitudinal ultrasonic waves and shear ultrasonic waves without a harsh sound protrusion can be transmitted and received.

Next, a method for displaying the crack propagation detection result according to an embodiment of the present invention will be described below. The creep wave and the mode converted wave are characterized in that the shear wave in the sample propagates at a lower speed than the axial wave.

Therefore, the ID creep wave and the mode converted wave require more propagation time until the probe receives the reflected wave, which only processes the propagation of the longitudinal wave compared to the conventional angled longitudinal wave crack spread detection technique.

Figure 7 shows the longitudinal wave propagation path of a 45 degree angled longitudinal wave (transmitting and receiving longitudinal waves at a 45 degree angle) A simplified diagram of this technique is widely used in angled longitudinal wave techniques. In this case, the longitudinal wave 701 from the ultrasonic sensor reaches the reflector 702, is reflected by a corner of the top of the reflector, returns to the ultrasonic sensor as a longitudinal wave 703, and is then signaled by the ultrasonic sensor.

Compared with the 45 degree angular longitudinal wave technique of Figure 7, the explanation with reference to Figures 4, 5 shows that the propagation path of the ID creep technique or the mode conversion technique of the present invention is more complicated and longer. Therefore, in order to properly display the reflected wave (echo), it is necessary to continuously display the echo for a suitable period of time according to a certain propagation time.

Therefore, in this embodiment, the length of time with respect to the multi-bottom echo generated in the sample is used as a criterion for determining the propagation time of the waveform display. 8A-8E are schematic diagrams showing an example of a phased array technique (incident angle of an electron scanning ultrasonic wave) for obtaining multi-bottom echo visualization and multi-reflection propagation paths in a flat sample.

The probe array is placed on the near surface of the sample, and multiple reflections are formed between the near surface and the distal surface of the sample. Figures 8A-8E summarize the types of echoes included in multiple reflections in ascending order of propagation time. Multiple backwall echoes come from five events that are actually received by the probe array.

Therefore, in the embodiment of the present invention, the recognizability of the ID creep wave and the mode converted wave is increased in consideration of the following five time lengths.

Corresponding to the first reverse echo time of the longitudinal wave in the case of wall thickness in the case of wall thickness; (Fig. 8A)

The sum of the one-way propagation time corresponding to the wall thickness of the longitudinal wave and the time of the one-way propagation time corresponding to the wall thickness of the shear wave; (Fig. 8B)

Corresponding to the second reverse echo time of the longitudinal wave's round-trip propagation time at twice the wall thickness; (Fig. 8C)

Corresponding to the single-pass propagation time in the case of three times the wall thickness of the longitudinal wave and the time of the one-way propagation time corresponding to the wall thickness of the shear wave; (Fig. 8D)

The sum of the round-trip propagation time corresponding to the wall thickness of the longitudinal wave and the wall thickness round-trip propagation time corresponding to the shear wave (Fig. 8E)

Here, the line 110 shown in the display system 103 in Fig. 1 represents the time (first back surface echo) corresponding to the longitudinal wave round-trip propagation time (corresponding to Fig. 8A or (1)). In other words, line 110 represents the distal surface of the sample. Similarly, line 111 represents the time corresponding to FIG. 8B or (2), line 112 represents the time corresponding to FIG. 8C or (3), and line 113 represents the time corresponding to FIG. 8D or (4), line 114. Represents the time corresponding to Figure 8E or (5).

As a display method for displaying a result according to the present invention, a line corresponding to a time length of a multi-bottom echo (or a distance obtained by multiplying a time length by a wave velocity), as shown in FIG. 1, or with a multi-echo The length of time (or the distance obtained by multiplying the length of time by the wave speed) corresponds to a concentric circle. It is also possible to combine two display methods.

Next, an example of a waveform recognition method according to an embodiment of the present invention will be described with reference to FIG. In this example, the execution target of the ultrasonic crack propagation detecting method is set to have a crack propagation (crack expansion) to the distal end surface thereof. When an echo is obtained as a crack extension indication (hereinafter referred to as "indication"), the area shown in Fig. 9 is checked for crack propagation, and the flow is as follows:

First, the normal angle crack propagation detection technique (S904) is used to check the presence or absence of the indication, and the angle in the angled axial wave crack propagation detection technique is set to about 45 degrees, or the position of the ultrasonic sensor (probe) is adjusted. The indication result of the angled longitudinal wave technique is displayed in the vicinity of the area 901 as shown in Fig. 9 (S905).

Finally, it is checked whether an echo in the area 903 appears to determine whether an echo caused by the ID creep wave (S906) is present. Finally, it is checked whether the echo in the area 902 appears to determine whether or not the echo caused by the mode converted wave (S907) occurs.

When a signal is found in step S904, S906 or S907, it is indicated that it is caused by crack propagation.

Here, the features of the region in which each of the signals in each of the steps in FIG. 9 (i.e., the

regions

901, 902 and 903 in Fig. 9) will be explained in detail before explaining the example of using the specific crack propagation detection. .

The depth of the distal surface is multiplied by 1/cos45 to obtain a 45 degree echo propagation distance. At the same time, the propagation time of the multiple echoes (1) is approximately 1.5 times that of the corresponding distal surface because the ratio V/Vs between the longitudinal wave velocity V and the shear wave velocity Vs in the solid is approximately 2, as shown in FIG.

Since the two propagation times are approximately equal, the reflected wave (longitudinal wave) received at about 45 degrees is displayed in the vicinity of the region 901 (where the arc B corresponding to the multiple echoes (2) intersects the 45-degree line).

In the judgment of the presence or absence of crack propagation using the ID creep wave, it is assumed that the probe array for the angled axial wave crack propagation detection is located at the angle θ shown in Fig. 7, which is about 45 degrees.

Therefore, the echo caused by the ID creep wave is displayed in the region 903 (enclosed by the two propagation times (Fig. 8C and Fig. 8E) and the crack propagation detection angle (70 degrees and 90 degrees) of the ID creep wave). And to determine whether there is crack propagation based on whether or not the signal in the area appears.

The waveform-converted wave is used to judge whether crack propagation is present, and the probe array used for the angled longitudinal wave crack propagation detection is assumed to be placed at the angular position shown in Fig. 7, which is about 45 degrees.

Therefore, the echo caused by the mode-converted wave is displayed in the region 902 (enclosed by the two propagation times (Fig. 8B and Fig. 8D) and the crack propagation detection angle (about 60 degrees) boundary of the mode converted wave), and Signal based on region The approximate height of the crack propagation can be judged.

The crack propagation height of the wave-type converted wave is allowed to receive the echo, and the wave velocity ratio V/Vs is 2, 1.5, and 2.5, respectively. In the graph, the longitudinal wave velocity V is fixed at 5900 m/s and the shear wave velocity is changed according to the wave velocity ratio V/Vs. Although there are slight differences in the three cases due to the difference in wave velocity ratio V/Vs (2 +/- 0.5), when the crack propagation height is close to 1/3 or more of the hull thickness, the echo caused by the wave-converted wave Can be received.

On the display screen, the near surface of the sample and the signal display area (corresponding to the range of incident angles and the propagation time of the ultrasonic waves are fanned) are displayed. For example, if the angle range is set to -5 to 85 degrees, the propagation time is set to the round-trip propagation time in the case of the total hull wall thickness of the longitudinal wave and the round-trip propagation time in the case of the hull wall thickness of the shear wave. .

In the signal display area, a received signal due to a plurality of echoes generated between the proximal end surface and the distal end surface of the sample is displayed as a multi-bottom echo signal. In this case, the crack propagation detection result can be roughly divided into the following three groups.

The first group is a case in which an indication in the angled longitudinal wave technique (about 45 degrees) is displayed in the area 901 (already explained with reference to FIG. 9), and an indication of the ID creep wave generation is displayed in the area 903 ( Also explained with reference to Figure 9, and the indication of the mode-converted wave generation is displayed in region 902 (also explained with reference to Figure 9).

In this case, since the indication is obtained by both the angled longitudinal wave and the ID creep wave, the echo of the portion considered (where the crack propagation may have been generated) is judged to be caused by the crack propagation. Since the wave-converted wave is also received, the crack propagation height is 1/3 or more of the thickness of the hull, and thus the crack propagation is considered to be a relatively large crack propagation.

The second group is a case in which an indication is obtained in the areas 901 and 903 (see FIG. 9), and no indication is obtained in the area 902.

In this case, both the angled longitudinal wave and the ID creep wave can provide an indication that the indication is considered to be caused by the crack propagation.

However, the crack propagation under consideration is judged to be a relatively small crack spread having a height slightly smaller than 1/3 of the height of the hull because no echo from the waveform conversion waveform is received in the region 902.

The third group is a case in which an indication provided only by the angled longitudinal wave is displayed in the area 901 (see Fig. 9). In this case, since some kinds of indications are obtained by angled longitudinal waves, some types of reflectors may be in the part under consideration (where crack propagation may have occurred); however, the reflector is judged not to be crack propagation.

These reflectors, rather than crack extensions, include, for example, deformation or staining of the distal surface of the sample (from the hull of the unmanned vessel) due to welding or other processing.

Here, when there is crack propagation on the distal end surface of the sample in the first and second cases, echoes from both the angled longitudinal wave and the ID creep wave can be obtained.

At the same time, when the deformed portion, such as the pierceable curl caused by welding, is present on the distal surface of the sample, an indication of the angled longitudinal wave is received. The sample does not have a crack-like reflector that extends vertically from the distal surface.

Therefore, the ID creep wave does not reflect on this reflector (transparent curl caused by soldering, etc.), and is not caused by crack propagation caused by ID creep waves or wave-converted waves. .

On the other hand, when the sample is identified as having crack propagation, the height estimation of the crack propagation (crack propagation) is based on the angled longitudinal wave (based on the echo 3102 from the crack propagation tip and the echo 3101 from the corner crack) The echo shown.

Here, when an inappropriate cell pitch (different from the optimal cell pitch according to an embodiment of the present invention) is used, the longitudinal wave and the shear wave are transmitted at a predetermined angle due to the absence of an appropriate cell pitch. A harsh sound protrusion is produced in the sample, so the multi-bottom echo signal is displayed on portions of the screen according to an angle different from the predetermined teaching.

The signal caused by the harsh sound protrusions (such as noise on the screen) affects whether or not a signal is generated in the

regions

901, 902, and 903.

As described above, according to the first embodiment of the present invention, the probe array having the optimum sectional bus bar is used (the transmission of the main beam of both the longitudinal wave and the shear wave and the reduction of the harsh sound protrusion are obtained), corresponding to the longitudinal wave The received signal at the time of the round-trip propagation time in the sum of the wall thicknesses and the round-trip propagation time in the case of shear wall thickness is displayed on the screen, five times of bottom echoes (Fig. 8A-8E) and the incidence of ultrasonic waves. In particular, the angle needs to consider the received signal, so that even with the use of the probe array, it can provide increasing reliability, in addition to the ordinary angled longitudinal wave technology, it can realize the ultrasonic creep propagation of the ID creep wave technology and the wave pattern conversion technology. Detection method and ultrasonic crack extension detector.

In addition, since the number of times of multiple bottom echoes is directly obtained from multiple bottom echoes caused by the probe array, wherein the probe array is used for ultrasonic crack propagation detection in the examples of Figures 1, 8A-8E, etc., embodiments of the present invention It is also possible to measure the number of times of the bottom echo by using the probe to emit ultrasonic waves in the vertical direction and use the measured test.

At the same time, when the longitudinal/shear wave velocity in the sample and the wall thickness of the sample are known, the number of times of the bottom echo can be obtained by calculation (by dividing the wall thickness by the longitudinal/shear wave velocity, etc.). When the shear wave velocity in the sample is not known, the half of the longitudinal wave velocity can be used for a rough estimation of the shear wave velocity.

Example 2

Next, ultrasonic crack propagation detection is suitable for the case where the sample has crack propagation (crack propagation) to its near surface, which will be described as a second embodiment of the present invention. The probe array in the second embodiment and the system composition for crack propagation detection are the same as those of the first embodiment.

Therefore, the following detailed explanation will be based mainly on the crack extension detection result display and the waveform identification. Ultrasonic transmission path for crack propagation detection using angled longitudinal wave techniques for finding crack propagation to the near surface of the sample Slot expansion), there are two cases, one is that the crack expansion height (depth) is relatively small, and the other is that the crack expansion height is relatively large.

The crack propagation height is small, the longitudinal wave from the ultrasonic sensor is reflected near the corner of the crack extension reflector, and the reflected longitudinal wave is directly returned to the ultrasonic sensor and received as a signal.

Longitudinal waves propagate in a direction corresponding to the angle of incidence, between approximately 70 and 90 degrees. Such a longitudinal wave is called an "OD creep wave."

The crack spread height is large, the longitudinal wave from the ultrasonic sensor is reflected near the tip of the crack extension reflector, and the reflected longitudinal wave is directly returned to the ultrasonic sensor and received as a signal. The incident angle 1804 of the longitudinal wave is approximately 60 degrees (approximately between 45 and 70 degrees).

When the reflector expands into a crack having a certain height (depth), the longitudinal wave reaches the tip of the crack extension or somewhere on the crack propagation surface on the way to the top end. The longitudinal wave reflected by the crack spread directly passes through the sample back to the ultrasonic sensor and is received as a reflected wave (echo) from the crack extension.

However, when the height of the reflector is relatively small, the crack propagates, and the longitudinal wave (generated by the shear wave passing through the wave pattern at the distal end surface of the sample) cannot reach the tip end of the crack propagation, and the tip does not generate ultrasonic waves returning to the ultrasonic sensor.

As mentioned earlier, crack propagation detection using wave patterning techniques is used to find crack propagation to the near surface of the sample (from wave-type transition crack propagation detection of surfaces that may have significant crack propagation) to assess whether potential crack propagation is Has a considerable height (approx. 2/3 of wall thickness).

Next, when performing crack propagation detection in order to find crack propagation to the near surface of the sample, the waveform identification method assumes that ultrasonic crack propagation detection is performed for a sample having crack propagation (crack expansion) to its near surface test. When an echo (indication) that may indicate crack propagation is obtained, it is judged whether or not crack propagation exists according to the following procedure.

First, the presence or absence of the crack is detected by a normal angled crack detection technique (S2004). In this step, the echo that has been reflected near or near the tip of the crack propagation (crack extension) is detected according to the crack propagation height, as described above.

Subsequently, the position of the ultrasonic sensor is adjusted such that an indication from the crack-expanding tip is displayed near the region 2001 or as if an indication from the corner crack is displayed near the region 2003 (S2005).

Finally, it is checked whether an echo occurs in the area 2002 to determine whether or not an echo caused by the mode-converted wave occurs (S2006). When a signal is found in step S2004 or step S2006, the indication is considered to be due to crack propagation.

Here, before using the specific example of interpreting crack propagation detection. The characteristics of each region (2001, 2002, 2003) that appears in each step of the signal will be explained.

The total number of times the echo is propagated from the crack-expanding tip by the angled longitudinal wave crack propagation detection method. This is the total number of paths and the number of times the bottom echo is propagated, and the total number of echoes from the corner crack surface using the OD creep wave method.

Further, when the wave speed ratio V/Vs is 2, 1.5 and 2.5, respectively, the longitudinal wave speed V is set at 5900 m/s and the shear wave velocity Vs varies according to the wave speed ratio V/Vs.

Area 2001

Angled crack propagation detection is used to select crack propagation from the crack-expanding open surface side of the sample (typical solids have a wave speed ratio in the range of 2 +/- 0.5), and the propagation time of the echo from the crack-expanding tip has a certain The propagation path, the propagation time of the echo from the corner crack, has a certain propagation path from the OD creep wave (longitudinal wave 70 degrees - 90 degrees) similar to the propagation time of the first bottom echo in the sample (Fig. 8A).

In particular, this relationship is also satisfied in the case of a 60-degree longitudinal wave (waveform converted waves are important). Therefore, in addition to the echo obtained by the angled longitudinal wave technique, the echo of the angular crack caused by the OD creep wave is in the vicinity of the region 2003 (here, the round-trip propagation time of the longitudinal wave wall thickness (Fig. 8A) and one The angular extents overlap, the angle of refraction is approximately between 70 and 90 degrees, and the crack-expanding tip echo caused by the angled longitudinal wave is near the region 2001 (here the round-trip propagation time in the case of wall thickness (Fig. 8A) ) overlaps with an angular range with a refraction angle of approximately 60 degrees.

Area 2002

In the process of judging whether crack propagation exists using a mode-converted wave, it is assumed that an indication resulting from the angled longitudinal wave crack propagation detection has been displayed in the area 2001 or displayed in the vicinity of the area 2001.

The ordinary solid wave velocity ratio V/Vs is approximately in the range of 2 +/- 0.5, even if the crack propagation detection angle for receiving the crack extension tip echo in the angled longitudinal wave technique deviates from 60 degrees by about 5 degrees, the mode conversion The round-trip propagation time of the wave is still at a time corresponding to the following two times: the sum of the single-pass propagation time of the longitudinal wave at three times the wall thickness and the one-way propagation time of the shear wave at the wall thickness (Fig. 8D) and Corresponding to the one-way propagation time of the longitudinal wave in the case of wall thickness and the one-way propagation time of the shear wave in the case of wall thickness (Fig. 8B).

Therefore, the echo caused by the mode-converted wave is displayed in the region 2002 (enclosed by the two propagation times (Fig. 8B and Fig. 8D) and the crack propagation detection angle boundary (about 60 degrees) of the mode converted wave). And the approximate height of the crack spread can be judged based on whether or not the signal in the region appears.

The crack propagation height of the echo caused by the waveform-converted wave is allowed to be received, wherein the wave velocity ratio V/Vs is 2, 1.5, and 2.5, respectively, the longitudinal wave velocity is fixed at 5900 m/s, and the shear wave velocity is varied according to the wave velocity ratio V/Vs. Although there is a slight difference in the wave velocity ratio V/Vs (2 +/- 0.5) in three cases, when the crack propagation height is approximately 2/3 or more of the wall thickness, the wave-type converted wave is caused. The echo can also be received.

Next, according to the crack propagation judging method of the embodiment, when the crack propagation detection in the drawing is performed, the sensor (probe) array is placed on the sample, explained with reference to FIG. 1, and there may be crack propagation in the sample ( Crack propagation) is assumed to be to the near surface of the sample.

On the display, the near surface of the sample and the signal display area (fanned to the angle of incidence and the propagation time of the ultrasonic wave) are displayed.

For example, the incident angle is set in the range of -5 degrees to +85 degrees, and the propagation time is set based on the sum of the longitudinal wave and the round-trip propagation time in the case of the back wave propagation time and the shear wave wall thickness.

In the signal display area, a signal is received as a plurality of bottom echo signals for display due to multiple reflections between the near surface and the distal surface of the sample. In this case, the crack propagation detection results can be roughly divided into the following three groups.

The first set of cases is that the angled longitudinal wave technique (approximately 70 degrees - 90 degrees) forms an indication of a portion near the corner crack from the sample that appears in area 2003, the formation of an angled longitudinal wave technique The indication from the crack extension tip is shown in area 2001. And an indication formed by the mode-converted wave is displayed in the area 2002.

In this case, since it appears that the indication from the corner crack is obtained by the angled longitudinal wave technique, the echo from the portion to be considered in which the crack propagation may have occurred is judged to be caused by the crack propagation. Since the indication caused by the mode-converted wave is also received, the crack propagates to a considerable crack propagation after the judgment, and the height of the oil (i.e., the depth measured from the near surface) is about 2/3 or more of the wall thickness.

In this step, the indication obtained by the longitudinal wave technique appears to come from the discontinuity with the crack extension. If the indication is estimated, the depth of crack propagation is consistent with the estimated wave-shaped converted wave (wall thickness 2/3 or more). Then, the crack propagation height (depth) is evaluated based on the echo from the crack-expanding tip portion obtained by the angled longitudinal wave technique.

If the two estimates are inconsistent, then it appears that the echo from the crack-expanding tip portion has captured the crack-expanding tip and therefore requires other detailed crack-expansion detection.

The second group is the case where an indication can be obtained within the

area

2001 and 2003 and no indication can be obtained within the area 2002.

In this case, since it seems that the indication from the corner crack portion is obtained by the angled longitudinal wave technique, it is judged that the indication is due to the existence of crack propagation. However, the crack propagation in the study is a relatively small mine with a height less than 2/3 of the wall thickness because the region 2002 does not receive echoes from the mode converted wave.

In this step, if the indication obtained from the angled longitudinal wave technique appears to be from the crack-expanding tip portion, the depth of crack propagation obtained by the evaluation is consistent with the estimated value of the mode-converted wave (less than the wall thickness 2/3), the crack The expanded height (depth) is evaluated based on the echo from the crack-expanding tip portion obtained by the angled longitudinal wave technique.

If the two estimated values are inconsistent, it seems that the echo from the crack extension tip has captured the crack extension tip. End, so other detailed crack extension detection is required.

The third case is that the display is performed in the area 2001 only by the angled longitudinal wave obtaining indication.

In the case of crack propagation detection to find crack propagation to the near surface of the sample (for crack propagation detection on surfaces that may have significant crack propagation), in many cases it is possible to use other methods that are different from ultrasonic crack propagation detection techniques. Techniques (eg, liquid intrusive leak detection, eddy current crack extension detection, visual inspection of the naked eye or camera) obtain the location of the corner fracture.

If the crack propagation position obtained by other techniques is consistent with the results obtained by the ultrasonic crack propagation detection technique, the indication displayed in region 2001 can be thought of as the echo from the portion of the sample near the corner crack.

In addition, if the crack propagation position detected by the ultrasonic crack propagation is contrary to the results obtained by other techniques, the indication displayed in the region 2001 may not be the echo from the corner crack, so it is necessary to require other crack propagation detection. In the former case, the crack propagation position detected by ultrasonic crack propagation is consistent with the results obtained by other techniques. It is judged that the crack propagates to a relatively small crack propagation, and the crack propagation height is less than 1/3 of the wall thickness because of the angled longitudinal direction. The wave technique does not obtain an echo from the crack extension tip portion, nor does it receive the echo from the waveform-converted wave.

If possible, it is best to compare the echoes displayed in region 2001 with the crack extension locations obtained by other techniques for the first and second cases (explained above for the third case) so that there is no Opportunities.

The height of crack propagation (crack propagation) can be estimated by judging that the sample has crack propagation.

Also in the second embodiment, in order to find crack propagation to the near surface of the sample, if the cell array used by the probe array is different from the cell pitch most suitable for reducing the harsh sound protrusion, then with the first embodiment Similarly, it is possible to return to the judgment of whether or not the signal appears in the

areas

2001, 2002 and 2003.

As described above, according to the second embodiment of the present invention, it is also used to find crack propagation to the near surface of the sample (crack propagation detection of a surface which may have significant crack propagation), wherein the probe array used is optimal The cross-section bus bar of the harsh sound protrusion is reduced, and the main beam of both the longitudinal wave and the shear wave can be transmitted, and the round-trip propagation time and the shear wave wall thickness in the case of the wall thickness of the longitudinal wave as follows In the case of the sum of the round-trip propagation time, the received signal is displayed within the corresponding time range. For the received signal, in particular, five times of bottom echo (Fig. 8A-8E) and the angle of incidence of the ultrasonic wave need to be considered, The signal provides an ultrasonic detection method with higher reliability, even if a probe array is used, capable of realizing a wave conversion technique other than the ordinary angled longitudinal wave technique.

In addition, as with the number of multi-bottom echoes shown in Figures 1, 10, etc., the number of times of multi-bottom echo caused by the probe array for ultrasonic crack propagation detection is not directly obtained, and it is also possible to emit ultrasonic waves by using the vertical direction. Extra The probe measures the number of times of multiple bottom echoes and uses the measured number of times.

At the same time, in the case where the axial/shear wave velocity in the sample and the wall thickness of the sample are known, the multi-bottom echo can also be obtained by calculation (dividing the wall thickness by the axial/shear wave velocity, etc.).

When the shear wave velocity in the sample is unknown, half of the longitudinal wave velocity may be used as a rough estimate of the shear wave velocity.

The present invention has been described with reference to the specific illustrative embodiments, and is not limited by the scope of the appended claims. It will be appreciated by those skilled in the art that the embodiments of the invention can be modified and modified without departing from the scope and spirit of the invention.

Claims

An ultrasonic detecting method for crack propagation in an unmanned ship hull, comprising the following steps:

(1) collecting a sample (100) as a detection object, establishing a probe array (101), transmitting ultrasonic waves into the sample (100), setting a transceiver (102), and a display system for displaying the received signal (103) );

(2) placing the probe array (101) on a defect detection near surface of the sample (100) and generating ultrasonic waves in response to a drive signal provided by the transceiver (102), the probe array (101) the emitted ultrasonic wave propagates through the sample (100), and the probe array (101) detects the reflected wave;

(3) generating a corresponding received signal from the probe array (101) according to the detected reflected wave echo, the received signal being input to the transceiver (102);

(4) The transceiver (102) includes a computer (102A), a delay controller (102B), a pulser (102C), a receiver (102D), and a data acquisition system (102E) from which the pulser ( a drive signal of 102C) is sent to the probe array (101), and the received signal output by the probe array (101) is processed by the receiver (102D), wherein the computer (102A) Controlling the delay controller (102B), the pulser (102C), the receiver (102D), and the data acquisition system (102E) to cause the components to operate normally;

(5) The data acquisition system (102E) processes the received signal from the receiver (102D) and sends the processing result to the display system (103).
The ultrasonic detecting method for crack propagation in an unmanned ship hull according to claim 1, characterized by: said step (5), wherein the process of receiving the received signal after the echo is obtained as a defect indication is as follows:

(5-1) First, the normal angle defect detection technique is used to check the presence or absence of the indication, and the angle in the angled axial wave defect detection technique is set to about 45 degrees, or the position of the ultrasonic sensor or probe is adjusted to form The indication result of the angled longitudinal wave technique is displayed in the vicinity of the area A, where the range of the area A is defined as: multiplying the depth of the distal surface by 1/cos45 to obtain the propagation of the 45-degree echo At the same time, the propagation time of multiple echoes is approximately 1.5 times that of the corresponding distal surface;

(5-2) Then, it is checked whether the echo in the area B appears to determine whether the echo caused by the ID creep wave appears, wherein the range of the region B is defined as: the judgment of the presence or absence of the defect by using the ID creep wave, A probe array for angled axial wave defect detection is located at an angle of approximately 45 degrees;

(5-3) Finally, it is checked whether the echo in the region C appears to determine whether the echo caused by the mode-converted wave appears, wherein the region C range is defined as: using the waveform-converted wave to determine whether the defect exists, the angled longitudinal wave The probe array used for defect detection is assumed to be placed at a position of approximately 45 degrees;

(5-4) When any of the steps (5-1) to (5-3) finds a signal indicating that it is caused by a crack defect.
The ultrasonic detecting method for crack propagation in an unmanned ship hull according to claim 1, wherein said delay controller (102B) controls a time at which the pulser (102C) outputs a driving signal and controls the receiver (102D). The input time of the received signal is sent so that the operation of the probe array can be obtained according to the phased array technique.
The ultrasonic detecting method for crack propagation in an unmanned ship hull according to claim 1, wherein the number of echoes is directly obtained or passed by the number of times of multi-bottom echo caused by the probe array for ultrasonic crack propagation detection. The number of times of multi-bottom echo is measured using an additional probe that emits ultrasonic waves in the vertical direction and is obtained using the measured number of times, or in the case where the axial/shear wave velocity within the sample and the wall thickness of the sample are known, The wall thickness is divided by the calculation of the axial/shear wave velocity.
The ultrasonic detecting method for crack propagation in an unmanned ship hull according to claim 1, characterized in that the probe array having the optimal sectional bus bar is used, that is, the transmission of the main beam of both the longitudinal wave and the shear wave is obtained, and the grating is obtained. The reduction of the sound protrusions, the reception signal in the time range corresponding to the round-trip propagation time in the case of the sum of the wall thicknesses of the longitudinal waves and the round-trip propagation time in the case of the shear wave wall thickness is displayed on the screen.
The ultrasonic detecting method for crack propagation in an unmanned ship hull according to claim 1, wherein the total number of times the OD creep wave is propagated from the corner crack surface in the step (5-2) is caused Whether the echo appears or not.