KR20180131898A - Ultrasonic Wave Flaw Detection Method And System For Recognizing Dead Zone Defects Using The Object's Self Vibration Analysis Function - Google Patents

Abstract

An ultrasonic wave flaw detection device is disclosed. The device comprises: a probe coming in contact with a detected object with a predetermined distance, generating an excitation signal toward the detected object, and receiving a vibration signal by the generated excitation signal; a signal separation module dividing the received vibration signal into an ultrasonic wave broadband and a self-unique frequency broadband of the detected object; and an analysis control unit analyzing a signal of the ultrasonic wave broadband and the self-unique frequency broadband. The analysis control unit determines that there is a defect in the detected object when a frequency pattern in the self-unique frequency broadband does not satisfy a predetermined standard.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to an ultrasonic inspection method and system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to an ultrasonic inspection apparatus and method, and more particularly, to an ultrasonic inspection technique and system capable of recognizing a dead zone defect due to the object itself having a vibration analysis function.

The non-destructive ultrasound flaw detection method is a method used to examine a target object by using ultrasound without destroying the target object. The ultrasonic flaw detection method is a flaw detection method for detecting defects of a target object by transmitting ultrasonic waves to a target object and analyzing signals of ultrasonic waves reflected from flaws existing therein. At this time, ultrasonic waves having a center frequency ranging from 0.1 to 15 MHz and sometimes up to 50 MHz can be used. Here, the above-described object is defined as a subject to be inspected or a subject to be inspected.

Ultrasonic waves are transmitted to a probe object through a probe and travel straight in the same medium (probe object). At an interface with a different medium (defect portion), the difference in physical state and properties (e.g., acoustic impedance) Thereby causing reflection or refraction.

Here, the transducer receives the reflected ultrasonic signal, and the defective part may be displayed as a pulse signal on the defective monitor. The position, type, size and the like of the defect can be measured by analyzing the defective part.

Hereinafter, general non-destructive ultrasonic inspection will be described with reference to Figs. 1 (a) and 1 (b). Ultrasonic waves are transmitted to the inspection object 20 through the transducer 19 of the transducer 10 once. At this time, a specific initial pulse wave appears, and a pulse wave reflected from a plurality of scratches 180a and 182a is reflected and measured (Flaw Echo 180b, 182b) The spa is measured 184b. In addition, the calibration should be performed due to the vibrator 19 and the gap 19a between the mediums.

At this time, even if the defect is located in the vicinity of the probe 10 very close to the probe object 20 and the reflective pulse wave 185 is generated due to the defect, the initial pulse may cause the pulse wave 185) is difficult to measure. Here, the point of the defect generated according to the flaw detection position of the probe 10 can be referred to as a dead zone.

That is, if the position of the defect to be detected in the ultrasonic inspection is sufficiently distant from the probe 10 by a predetermined distance, if a defect occurs in a portion directly under and immediately adjacent to the probe 10, Defects are not found, and thus there is a problem that the measurement of the test is inaccurate.

Accordingly, a technology for improving this problem will be required.

On the other hand, the above information is only presented as background information to help understand the present invention. No determination has been made as to whether any of the above content is applicable as prior art to the present invention, nor is any claim made.

Patent Registration No. 10-1704577 (Registered on February 27, 2017)

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-described problems, and an embodiment of the present invention proposes an ultrasonic inspection apparatus that recognizes occurrence of a dead zone when ultrasonic inspection is performed on a detection object.

Specifically, an embodiment of the present invention proposes an ultrasonic flaw detection apparatus that recognizes the occurrence of a dead zone at the time of flaw detection using the vibration eigenfrequency of the object to be detected.

In addition, an embodiment of the present invention proposes an ultrasonic inspection apparatus that divides an excitation signal generated in a probe into an ultrasonic wave band and a self-resonant frequency band of the object to be inspected.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to an embodiment of the present invention for realizing the above-mentioned object, an ultrasonic diagnostic apparatus according to an embodiment of the present invention is provided with an ultrasonic diagnostic apparatus that contacts a subject to be detected at a predetermined distance, generates a signal directed toward the object to be detected, A receiving probe; A signal separation module for dividing the received vibration signal into an ultrasonic wave band and a self-specific frequency band of the object to be detected; And an analysis control unit for analyzing the signals of the ultrasonic band and the self natural frequency band, wherein when the frequency pattern in the self-specific frequency band does not satisfy a predetermined criterion, .

According to various embodiments of the present invention, the dead zone of the inspection object can be easily found and the accuracy of the defect measurement can be increased.

Also, the accuracy and speed of the test measurement can be improved by providing an ultrasonic flaw detector that divides an excitation signal generated from a probe into an ultrasonic wave band and a self-resonant frequency band of the object to be inspected.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 (a) and 1 (b) are views for explaining a general non-destructive ultrasonic inspection method.
2 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to an embodiment.
3 (a) and 3 (b) show the frequency pattern corresponding to the case where no dead zone is generated.
4 (a) and 4 (b) show a frequency pattern corresponding to a case where a dead zone is generated.
5 is a flowchart showing a method of detecting a frequency bombarding instrument according to an embodiment.
FIG. 6 shows a method of calculating the distance between a probe point and a flaw of a probe object according to the embodiment.
Fig. 7 shows a method of calculating the length of the scratches inside the inspection object according to the embodiment.

The following detailed description, which refers to the accompanying drawings, will serve to provide a comprehensive understanding of the various embodiments of the present disclosure, which are defined by the claims and the equivalents of the claims. The following detailed description includes various specific details for the sake of understanding, but will be considered as exemplary only. Accordingly, those skilled in the art will recognize that various changes and modifications of the various embodiments described herein may be made without departing from the scope and spirit of this disclosure. Furthermore, the descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following detailed description and in the claims are not intended to be limited to the literal sense, but merely to enable a clear and consistent understanding of the disclosure by the inventor. Thus, it will be apparent to those skilled in the art that the following detailed description of various embodiments of the disclosure is provided for illustrative purposes only, and that the present disclosure, as defined by the appended claims and equivalents of the claims, It should be clear that this is not provided for the sake of clarity.

2 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus 100 according to the embodiment.

2, the ultrasonic testing apparatus 100 includes an excitation unit 110, a probe 120, a signal separation module 130, and an analysis control unit 140. The components shown in FIG. 2 are not essential to the implementation of the ultrasonic inspection instrument 100, so that the ultrasonic inspection instrument 100 described herein may include more or fewer components than the components listed above Lt; / RTI >

The exciting unit 110 is a module for generating a signal in the probe 120 contacting the probe. An excitation signal is a signal that generates vibration in a specific system. The exciter 110 is a module that applies vibration or an external force to generate a vibration in the inspection object.

The probe 120 is a component that receives a vibration signal as an input through a transducer from the time of generation of the ultrasonic wave. That is, the probe 120 generates an excitation signal and may receive a signal reflected on a defect, a rear wall, or the like.

The above-described excitation unit 110 and the probe unit 120 may be implemented together in a probe, but the embodiments are not limited thereto.

The signal separation module 130 is a component for dividing the received signal into an ultrasonic wave band and a self-resonance frequency band, including a natural vibration frequency calculation module of a detection object. The signal separation module 130 divides the received signal into a time domain domain and a frequency domain domain, Can divide the input signal. The self-resonant frequency band may correspond to a frequency band representing the natural vibration of the probe object.

The signal separation module 130 can separate input signals by applying windowing and filtering, which are signal processing techniques, but the embodiments are not limited thereto.

The analysis control unit 140 may analyze the signals of the ultrasonic band and the self-resonant frequency band. The analysis control unit 140 may include an ultrasound analysis unit 141, a self-vibration analysis unit 143, and a defect determination unit 145.

The analysis control unit 140 includes an ultrasonic analysis unit 141 for analyzing signals in the ultrasonic wave band, a self-vibration analysis unit 143 for analyzing signals in the self-resonant frequency band, and a defect determination unit 145).

The ultrasonic analyzer 141 analyzes the frequency to determine whether there is a reflected pulse in the ultrasonic band. At this time, the Fourier transform can be performed, but the embodiment is not limited thereto.

If there is a reflection pulse, the ultrasonic analyzer 141 can calculate the delay time of the excitation signal. Accordingly, frequencies at the time of ultrasonic transmission and reception can be analyzed.

The self-oscillation analysis unit 143 can determine whether the frequency pattern within the self-resonant frequency band satisfies a predetermined criterion. The self vibration analysis unit 143 can analyze the vibration power of the self resonance band.

For example, the self-oscillation analysis unit 143 may determine that the signal pattern of the self-resonant frequency band is weaker than the signal pattern of the self-resonant frequency band of the probe object in the pattern of the signal received through the probe 120 It can be determined that a dead zone has occurred.

In this case, the ultrasonic testing apparatus 100 can examine the object to be inspected by changing the detection position. Accordingly, the flaw included in the inspection object, in particular the measurement error due to the occurrence of the dead zone, can be improved.

2, a signal conditioner (not shown) for performing signal amplification, noise separation, and band-pass filtering on a vibration signal received by the probe 120, a conversion unit (not shown) for converting an analog signal into a digital signal, But the embodiment is not limited thereto.

3 (a) and 3 (b) show the frequency pattern corresponding to the case where no dead zone is generated.

3 (a) shows a situation in which the frequency-measuring device 100 generates a signal in a state in contact with the probe 20 and is reflected on the defect 182c.

3 (b), after the excitation signal is generated, the transmission ultrasonic wave band 205a, the self resonant frequency wave band 210a of the probe object, and the wave band 215a reflected by the flaw appear. The above bands appear sequentially in accordance with the passage of time.

Here, the frequency detecting device 100 can store a frequency waveform in which no dead zone is generated and use it for analysis. The frequency detecting device 100 can measure and store the self-resonant frequency of the probe object a plurality of times.

4 (a) and 4 (b) show a frequency pattern corresponding to a case where a dead zone is generated.

Fig. 4 (a) shows a situation in which the frequency-detecting device 100 generates a signal in a state in contact with the probe 20 and is reflected on the defect 182d. At this time, the distance between the scratch 182d and the frequency detecting device 100 is short, and a dead zone may be generated. That is, it is impossible to obtain the time difference between the excitation pulse and the reflection pulse, so that a dead zone can be generated.

4 (b), after the excitation signal is generated, the transmission ultrasonic wave band 205b and the self-resonant frequency wave bands 210b and 215b of the object are displayed.

Here, the frequency pattern of the self resonant frequency wave bands 210b and 215b has a different pattern from the frequency pattern of FIG. 3 (b). For example, the self-resonant frequency waveform band 210a of the probe object in FIG. 3 (b) is formed so that the signal value is wider than the self resonant frequency wave bands 210b and 215b of the probe object in FIG. 4 (b) . That is, the vibration amount of the self-oscillating frequency in Fig. 4 (b) is smaller than that in Fig. 3 (b).

The frequency detecting device 100 stores the natural frequency information of the probe object, and it can be determined that a dead zone is generated in the case of FIG. 4 (b). Accordingly, when the inspection is performed at a different position, the accuracy of the flaw measurement can be improved.

5 is a flowchart showing a method of flaw detection of the frequency measuring instrument 100 according to the embodiment.

Once a signal is generated in the probe object (S410), the probe 120 receives the vibration signal (S420). And thus the description thereof is omitted.

In step S430, the frequency detecting device 100 divides the received signal into an ultrasonic band and a self-resonant frequency band in step S430. If the self-resonant frequency is a predetermined pattern, it is determined that the object is defective in step S440. And thus the description thereof is omitted.

Fig. 6 shows a method of calculating a distance between a probe point and a flaw of a probe object according to the embodiment.

According to Fig. 6, the distance to the scratch 182f of the welded portion 510 can be expressed as W in the probe 100. [ W can be calculated by multiplying the ultrasonic velocity by time. Thus, the actual horizontal distance Y can be calculated by multiplying W by sin &thetas;, and the vertical distance d can be derived by multiplying W by cos &thetas;.

Fig. 7 shows a method of calculating the length of the scratches inside the inspection object according to the embodiment.

At the point where the defect appears, the waveform starts to move and the peak of the echo appears at the center of the defect. The waveform on the CRT may show a waveform at a certain point (for example, a half echo point) relative to the peak as the defect moves along the direction of the defect centering around the peak. These points can be the starting and ending points of the defect. The distance between the start point and the end point may be the distance of the defect.

Specifically, the point A2 in FIG. 7 has a peak at an echo of 80%, and the points A1 and A3 have a 40% echo at half the peak. This is because the ultrasonic beam passes through the non-defective part in one direction and the defect in the other direction.

A point of the blemish corresponding to A11 corresponds to A1, and a point of blemish corresponding to A31 corresponds to A3. Thus, the lengths of A1 to A3 can be calculated as the total length of the blemishes.

The present invention described above can be embodied as computer-readable codes on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, , And may also be implemented in the form of a carrier wave (e.g., transmission over the Internet). In addition, the computer may include a control module 400 of the ultrasonic inspection instrument 100. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

Claims (10)

In ultrasonic flaw detection,
A probe contacting the object to be detected at a predetermined distance to generate a signal directed toward the object to be detected and receiving a vibration signal based on the generated vibration;
A signal separation module for dividing the received vibration signal into an ultrasonic wave band and a self-specific frequency band of the object to be detected; And
And an analysis control unit for analyzing signals of the ultrasonic wave band and the self natural frequency band,
The analysis control unit,
And determines that there is a defect in the object to be detected if the frequency pattern within the natural frequency band does not satisfy a predetermined criterion. The method according to claim 1,
The signal separation module comprises:
And separates the received vibration signal into a plurality of signal waveforms based on a time domain and a frequency domain. The method according to claim 1,
The analysis control unit,
Calculating a delay time of the excitation signal with respect to the reflected pulse pattern of the ultrasonic frequency and analyzing the vibration amount of the frequency in the self-intrinsic frequency band; judging that the object to be inspected has a defect if the vibration amount is within a predetermined range; Ultrasonic flaw detection device. The method according to claim 1,
The analysis control unit,
And determines at least one of a position, a type, and a size of the defect when the defect is found in the object to be inspected. 5. The method of claim 4,
The analysis control unit,
Measuring a defect center portion with a CRT (Cathode Ray Tube) waveform, measuring a CRT waveform before and after the measured defect center portion,
And calculates the distance between the first defect point and the second defect point corresponding to each of two points satisfying a specific same size among the CRT waveforms before and after the measured defect center as the length of the defect. In a flaw detection method using an ultrasonic flaw detection apparatus,
Generating a signal directed toward the object to be detected, and receiving a vibration signal based on the generated vibration signal;
Dividing the received vibration signal into an ultrasonic wave band and a self-specific frequency band of the object to be inspected; And
And judging that the object to be detected is defective when the frequency pattern in the self-specific frequency band does not satisfy a predetermined criterion. The method according to claim 6,
Wherein the distinguishing step comprises:
And separating the received signal into a plurality of signal waveforms based on a time domain and a frequency domain. The method according to claim 6,
Wherein the determining step comprises:
Calculating a delay time of the excitation signal with respect to a reflected pulse pattern of an ultrasonic frequency;
Analyzing a vibration amount of the frequency within the self natural frequency band; And
And judging that the object to be detected is defective when the vibration amount is within a predetermined range. The method according to claim 6,
And determining, when a defect is found in the object to be detected, at least one of the position, type, and size of the defect. 10. The method of claim 9,
Wherein the step of determining the size of the defect comprises:
Measuring a defect center portion with a CRT (Cathode Ray Tube) waveform, and measuring a CRT waveform before and after the measured defect center portion; And
Calculating a distance between the first defect point and the second defect point corresponding to each of two points satisfying a certain same size among the CRT waveforms before and after the measured defect center as the length of the defect.

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