JP2010243375A - Extended crack detection method, apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extended crack detection method, an apparatus, and a program for surely detecting a regular extended crack or more without overlooking it. <P>SOLUTION: The extended crack detection apparatus includes: an ultrasonic wave generating means 10 for entering ultrasonic waves 220 into a to-be-inspected object 200; a material noise receiving means 20 receiving a material noise 230 from the to-be-inspected object; a material noise information processing means 30 for processing the material noise received by the material noise receiving means as material noise information if the ultrasonic wave generating means 10 is moved in a predetermined range; a recording means 40 for recording a processed result as initial material noise information 400-1; a material noise information comparing/processing means 50 for comparing temporal material noise information 400-2 obtained by implementing the similar measurement and process on the to-be-inspected object after the predetermined time is elapsed with the initial material noise information called from the recording means; and an extended crack information determining means 60 for obtaining information on the extended crack from a comparison result of the material noise information comparing/processing means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a progress crack detection method, apparatus, and program for nondestructively detecting a progress crack of an inspection object that progresses over time, for example.

  In buildings such as ships, bridges, and nuclear facilities, in order to ensure the safety of the structure, periodic inspections are conducted to confirm and evaluate the occurrence of cracks. In order to search for cracks in steel materials used in structures, ultrasonic flaw detection tests are used exclusively due to the limitations of the usage environment.

  However, in the case of planar defects such as cracks, it is difficult to make ultrasonic waves incident from the front direction, and it is necessary to detect echoes from the edge of the defect when ultrasonic waves are incident from an oblique direction. There is. The echo from the defect end is buried in the material noise (forest echo) in the case of a defect having a very small tip curvature, such as a fatigue crack, and it may be difficult to detect normally.

  Moreover, when a defect is located in the vicinity of the welding surplus part, the echo generated in the surplus part and the defect echo may not be distinguished, and there is a high risk of missing the defect. In fact, there has been an example in the past where a fatigue crack over almost the entire circumference of a piping in a nuclear facility was missed.

  The ultrasonic flaw detection test has been developed to detect defects with round welds, but these defects have relatively large echoes and are not easily affected by fluctuations in the incident direction. Has advantageous properties.

  In recent years, a TOFD method (Time of Flight Diffraction) has been developed as a new flaw detection method for cracks due to a demand for enhanced crack exploration. In this method, the ultrasonic wave generated by the transmitting probe is incident on the crack, and the echo (diffracted wave) from the upper end of the crack and the echo (diffracted wave) from the lower end are placed at a position sandwiching the crack. This is a method of detecting the upper and lower end positions of the crack by detecting with a receiving probe. In the field measurement, echoes other than the upper-end echo and the lower-end echo may be detected, and a large difference occurs in the result depending on which echo is regarded as the upper end or the lower end. Another problem is that there is no standard for discriminating between noise echoes and defect echoes, and it is left to the judgment of the flaw detector.

  As described above, the conventional ultrasonic flaw detection test lacks the certainty of crack exploration. That is, at present, it is possible to detect a minute defect, but the probability of missing a large crack-like defect is not low. The crack of the material is a safety threat because if it is left undiscovered, it may lead to the destruction of equipment and facilities due to the breakage of the material.

  On the other hand, the damage degree of a structure is predicted based on the use history and use conditions of a ship or a building, and the remaining useful life of a member related to the structure is calculated or creep damage is detected. . As a method for nondestructively evaluating a defect or deterioration state of a structure, there is a method in which an ultrasonic wave is incident on an inspection object and defect detection processing is performed based on waveform data of a reflected wave.

  For example, there are technical ideas disclosed in the following Patent Documents 1 to 3 for confirming the occurrence of cracks or the like in a predetermined structure.

Patent Document 1 is an ultrasonic flaw detection device that detects a defect generated inside a subject, corrects a cross-sectional image using a feature amount common to a plurality of cross-sectional images, and performs false detection of a flaw by a pseudo echo. The technical idea to reduce is disclosed. However, the ultrasonic flaw detector disclosed in Patent Document 1
This is a method for detecting a common defect image in a plurality of cross sections, and requires that the defect shape be uniform over the plurality of cross sections, and that the defect echo be equal to or higher than the material noise. In the case of defects with extremely small tip curvature, such as fatigue cracks, the problem that defect echoes are buried in material noise and difficult to detect cannot be overcome.

  In Patent Document 2, ultrasonic waves are incident on the entire thick part of the pipe in a pipe state detection method in which ultrasonic waves are incident on the thick part of the pipe and the reflected wave from the discontinuous part of the pipe is analyzed to detect the state of the pipe. Then, a pipe state detection method for detecting thinning by comparing the difference between the initial waveform data and the waveform data collected thereafter and the allowable amplitude is disclosed. However, the pipe state detection method disclosed in Patent Document 2 is intended for inspection of pipe thinning, and the evaluation of differential waveform data is based on a preset amplitude (determined by a noise level or the like). Therefore, if the echo height from the defect is small and less than the material noise, it cannot be detected.

  Patent Document 3 discloses a new scratch detection method and scratch detection apparatus for a rental car that compares and calculates exterior surface data of a rental car before rental and exterior surface data after return, and determines the presence or absence of scratches from the difference. However, in the novel flaw detection method and apparatus disclosed in Patent Document 3, what is detected is a flaw on the surface of the car, not an internal crack. Moreover, it is necessary to remove crack information noise when imaging the measured crack information. In this case, it may be difficult to determine the presence or absence of a flaw depending on the noise removal efficiency.

JP 2008-122187 A JP 2008-32466 A Japanese Patent Laid-Open No. 11-144042

  As described above, even if there is a technique for detecting a crack non-destructively, there is no certainty in the conventional techniques, and thus there is a great safety problem. It can be said that the condition that cracks cannot be detected is a practical problem especially in facilities that have a significant impact on the safety of citizens and citizens, such as ships, bridges, and nuclear power plant facilities. I do not get.

  In this regard, there is also a concept of performing nondestructive inspection of materials using X-rays. However, in the case of using X-rays, it is difficult to detect an object with a large thickness as an inspection target, and it is not suitable for use in a daily environment. It is necessary to provide.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and an object of the present invention is to provide a progress crack detection method, apparatus, and program that can detect a progress crack above a certain level without oversight.

  In order to solve this problem, the crack detection method according to claim 1 according to the present application includes a step of moving an ultrasonic wave generating means within a predetermined range to an object to be inspected and entering the ultrasonic wave, and the object to be inspected. Receiving the material noise from the step, recording the received material noise as initial material noise information, and setting the ultrasonic wave generation means to the inspection object again after the elapse of time to approximately the predetermined range or the same. A step of moving ultrasonic waves in a close range to receive ultrasonic waves, a step of receiving material noise after time from the inspection object, and comparing the received material noise after time with the initial material noise information as material noise information after time And a step of obtaining information on the progress crack from the result of the comparison.

  “Move within a predetermined range and make an ultrasonic wave incident” means that an ultrasonic wave is incident while scanning the ultrasonic wave generation means by selecting a place where a crack is expected to occur in advance, or without hitting, A mode in which a probe (described later) is randomly scanned on the material surface may be used.

  The object to be inspected is a material that constitutes a building such as a ship, a bridge, or a nuclear power generation facility, and that may cause a crack inside. The material of the object to be inspected is typically a carbon steel or SM material having a polycrystalline structure, other steel materials, or other metal materials, but is limited to these as long as material noise can be detected. Not.

  “Material noise” refers to noise generated by a material and does not include electrical noise, and is generated by scattering of ultrasonic waves by crystal grains of the material. The material noise generated by many crystal grains is ultrasonic vibration, but these are returned to the probe and detected as an electrical material noise signal. The ultrasonic wave generation means has a function of generating a predetermined ultrasonic wave, and may have a function of generating an ultrasonic wave while scanning the probe by human operation or automatic control. Specifically, it can be realized by a probe including a transducer that can generate material noise by entering an ultrasonic pulse. The frequency and waveform of the generated ultrasonic pulse are optimized in order to efficiently generate material noise. Preferably, the pulse width (duration) is long and the frequency is high. However, if the pulse width is too large, the resolution will be reduced, and if the frequency is too high, the flaw detection depth will be reduced due to excessive attenuation. Therefore, it is preferable to select an optimal value in relation to the measurement target.

  "Receiving material noise from the object to be inspected" means receiving material noise generated when the ultrasonic wave incident from the ultrasonic wave generator enters the microscopic structure (including crystal grains) of the material. This fine structure includes, in addition to the normal structure (crystal grains) of the material, a structure (crystal grains) altered by creep, plastic deformation, or the like.

  The material noise receiving means can be exemplified by a material having a function of receiving material noise returned from crystal grains by the incidence of ultrasonic waves using a piezoelectric element, a mechanoelectric conversion element, or the like. The material noise receiving means may be included in the ultrasonic wave generating means and may be an integrated type.

  “Record material noise as initial material noise information” means that the received material noise related to a specific part is processed as initial material noise information, and the processed information is electrically and / or magnetically and / or optically. Examples include recording on a recording medium (including a memory built in the apparatus and an external memory; the same applies hereinafter).

  The material noise information processing means is at least one of a function of performing numerical conversion processing or image conversion processing by predetermined arithmetic processing so that material noise can be recorded, and a function of detecting detected material noise signals and extracting amplitude information. It can be illustrated by what has.

  “After the elapse of time, the ultrasonic wave generation means is again moved within a predetermined range with respect to the object to be inspected so that the ultrasonic wave is incident”. It can be exemplified by an ultrasonic wave incident by moving the generating means within a predetermined range at the time of initial material noise acquisition or in the vicinity thereof.

  “Receiving material noise after the lapse of time from the object to be inspected” is generated by injecting ultrasonic waves from the ultrasonic wave generation means to the material structure (including crystal grains) after a predetermined time has elapsed. Can be exemplified by those receiving material noise, which can include receiving with or without crack growth.

  “Comparing material noise after time with initial material noise information as material noise information after time” means that material noise received after a certain period of time is processed as material noise information after time that is compared with initial material noise information And can be exemplified by what is compared with the recorded initial material noise information.

  “Obtain information on progress cracks from the comparison results” means that the presence of cracks, amount of progress, progress rate, direction of progress, position of progress cracks, future predictions, and other progress from the results of comparison of the above material noise information. It can be exemplified by what obtains information, and typically includes visualizing using a pseudo color associated with each predetermined numerical range of the deviation for a certain deviation in the comparison result. it can.

  By providing these steps, ultrasonic waves are incident on the predetermined range of the object to be inspected by the ultrasonic wave generation means, and the scattered waves generated from the crystal grains in the ultrasonic wave propagation range are synthesized. Material noise is formed at the probe position or scanning range, and this material noise is received by receiving means, etc., and processed and recorded as initial material noise information. Information is acquired and compared as initial material noise information and after-time material noise information. By obtaining predetermined information on the progress of cracks in the ultrasonic propagation range from the result of comparison, the progress of cracks can be recognized, the cause of crack generation can be investigated, and crack generation can be prevented.

  Further, in the above method, the progress crack detection method according to claim 2 of the present application is configured to confirm the generation of the material noise in the step of receiving the material noise and / or the step of receiving the material noise after the lapse of time. May be.

  By providing such steps, it is possible to immediately recognize a state where a probe as a means for generating ultrasonic waves, a means for receiving material noise, or the like, a coupling failure related to transmission / reception of ultrasonic waves, It is possible to prevent a decrease in reliability of the inspection due to erroneous measurement.

  In the above method, the progress crack detection method according to claim 3 of the present application is the difference between the initial material noise image as the initial material noise information and the post-aging material noise image as the temporal material noise information in the comparing step. It is good also as composition which takes.

  In order to obtain the difference between the initial material noise image and the material noise image after lapse of time, for example, an algorithm that obtains a difference between numerical values as image information and extracts the difference value that is not within a certain threshold value is used. It is also possible to use an algorithm that superimposes the initial material noise image and the material noise image after time and processes the difference in crack shape as an image.

  By providing these steps, the difference between the images can be recognized from the shape, dimensions, or feature points of the initial material noise image and the material noise image after the lapse of time, so that changes accompanying crack growth can be observed on the difference image. Thus, the progress crack can be easily evaluated. Furthermore, when processed as an image, for example, if a pseudo color is assigned and visualized according to the difference value, it can be visually recognized by a person other than those skilled in the art, and the detection of the progress crack is further ensured.

  In the above method, the progress crack detection method according to claim 4 of the present application may be a method of taking a pattern matching at the time of superimposing the initial material noise image and the material noise image after time in the step of taking the difference. .

  Taking pattern matching can be exemplified by determining a reference position for superposition when superimposing and comparing the initial material noise image and the material noise image after time. For example, a method for obtaining the feature points of each of the initial material noise image and the material noise image after aging (for example, the position of the center of gravity of the pattern, density, length, main axis straight line, etc.) or setting a frame (window) within a certain range The reference position can be determined by a method of obtaining the number of white or black pixels in the frame, and the difference between the images can be extracted by superimposing both images at the reference position.

  By providing such steps, the position of the inspection target can be adjusted by simply injecting the ultrasonic wave within the approximate range of the inspection target portion, and the advanced crack can be accurately detected.

  In order to solve the above problem, a progress crack detection program according to claim 5 of the present application is a progress crack detection program that causes a computer to execute the steps of the progress crack detection method.

In this case, since a series of steps can be executed according to instructions from the computer, the procedure of the steps, progress, recording, processing, etc. can be executed automatically or semi-automatically according to the instructions of the computer. It is possible to measure correctly, quickly and reliably without relying on

  Moreover, in order to solve the said subject, the progress crack detection apparatus which concerns on Claim 6 of this application is the material which receives the ultrasonic wave generation means which injects an ultrasonic wave with respect to a to-be-inspected object, and the material noise from the said to-be-inspected object Noise receiving means, material noise information processing means for processing material noise received by the material noise receiving means when the ultrasonic wave generating means is moved within a predetermined range as material noise information, and the material noise information processing means Recording means for recording the processing result as initial material noise information, and the material noise information after time obtained by performing similar inspection and processing on the inspection object again after time, and the recording means called from the recording means Material noise information comparison processing means for comparing initial material noise information, and progress crack information for obtaining information on progress cracks from the comparison result of the material noise information comparison processing means Constituted by and a disconnection means.

  Functions related to the ultrasonic generation means, material noise reception means, material noise information processing means, recording means, material noise information comparison processing means and progress crack information determination means are the same as described above, but specifically, Machine, device, component having each function, algorithm for causing computer to execute such function, program for realizing this algorithm, software including this program, mounted medium, ROM (read only memory), or these It is realized by a computer or the like with or built in.

  By providing such a configuration, ultrasonic waves are incident on a predetermined range of the object to be inspected by the ultrasonic wave generating means, and material noise is formed at the probe position or scanning range. This material noise is received by the receiving means or the like. While receiving and processing / recording this as initial material noise, such material noise information is acquired again after a certain time as material noise information, and each of them is subjected to comparison processing by comparison processing means. By recognizing predetermined information on the progress of cracks in the ultrasonic propagation range from the comparison result, it is possible to investigate the cause of cracks and prevent cracks from occurring.

  Further, in the above configuration, the progress crack detection device according to claim 7 of the present application may further include a correction unit that corrects the influence of the propagation distance of the ultrasonic wave incident on the inspection object. it can.

  In general, as the ultrasonic wave propagates through the object to be inspected, the ultrasonic intensity decreases due to the influence of the acoustic properties of the material itself and the scattering based on the material structure, and the intensity of the material noise also increases. descend. In order to eliminate the influence of this phenomenon on the detection sensitivity of cracks, the average material noise level even if the ultrasonic propagation distance is different in the method of this application that extracts the crack information from changes in the material noise. It is desirable to analyze the change information while keeping the same. Therefore, the material noise level can be made uniform by correcting the influence of the propagation distance of the ultrasonic wave by the correcting means.

  Here, the correction means is a method for correcting the material noise level using a calibration curve created using a reference test piece made of the same material as the object to be inspected, and the ultrasonic propagation distance is different and obviously cracks are generated. It can be exemplified by means for correcting the level of material noise in a non-place to be uniform. When the ultrasonic attenuation of the material related to the object to be inspected is quantitatively known, a calibration curve may be created numerically and used for correction.

  By having such a configuration, the material noise level at the shallow and deep positions of the object to be inspected is made uniform, and the reliability of the material noise at the deep position is prevented from being lowered. It can be made uniform.

  In the above configuration, the material noise information processing means in the progress crack detection apparatus according to claim 8 of the present application detects the detected material noise signal to extract amplitude information, and the material noise information comparison processing means detects the detected material noise signal. The initial material noise information after processing and the material noise signal after aging can be compared as an amplitude image signal.

  The amplitude information can include information indicating a detected waveform and can be exemplified by information that can be compared and compared between waveform patterns.

  The amplitude image signal can be exemplified by a signal obtained by detecting and image-processing the initial material noise information and the material noise signal after the elapse of time for use in image comparison.

  With such a configuration, the detected material noise signal information is compared, so that not only can the material noise signal be directly processed, but also the processing of the signal processing apparatus can be reduced.

  Further, in the above configuration, the progress crack detection apparatus according to claim 9 of the present application further includes image display means for displaying a judgment result of the progress crack information judgment means, and at least the material noise information processing by the image display means. The processing result of the means can also be displayed.

  An image display means can be illustrated by what has the function to display the judgment result of a progress crack information judgment means and / or a material noise information processing result on a display etc. FIG. When the determination result is displayed, it may be displayed as electronic information using a predetermined application.

  By providing such a configuration, the operator can visually confirm the detected material noise comparison result with an image, so that the detection result can be easily obtained, and mechanical detection and human confirmation are overlapped. By combining them, the certainty of detection can be ensured. As a result, the detection time can be shortened, and the work efficiency is improved.

  According to the present application, since information on crack progress is obtained from a comparison result of initial material noise information and material noise information after time using material noise caused by ultrasonic incidence, highly reliable crack progress information is obtained. Can do. In other words, it does not use echoes from defects whose echo height is unstable, but uses changes in material noise based on changes in the ultrasonic propagation path. Can be reliably detected and evaluated. In particular, a crack having a large progress amount in the cross-sectional direction of the ultrasonic beam can be reliably detected.

  Also, since material noise is used, material noise is always detected if the equipment is normal. Therefore, if there is a problem with the ultrasonic wave generation means or material noise reception means, the abnormality can be immediately determined, and inspection is performed. Can improve the reliability. In other words, in ultrasonic measurement, various factors (such as the state of acoustic coupling between the probe and the test piece, failure of the ultrasonic equipment, external electrical noise, etc.) may cause a decrease in sensitivity and waveform disturbance. Although reliability and certainty are often impaired, material noise that directly reflects such measurement failures is observed and used in this application, so measurement failures can affect the detection of crack initiation and progress. The influence can be eliminated in advance, and the reliability of the inspection is greatly improved.

In addition, by taking the difference between the initial material noise information and the material noise information after the lapse of time, it is possible to detect truly dangerous progressing cracks, not static cracks, and progress even in the presence of interference echoes such as weld overlays. Cracks can be easily detected.

  Further, by performing pattern matching, the inspection target position can be matched even if there is a deviation in a predetermined range between the initial measurement and the measurement after the lapse of time, and the progress crack can be accurately detected.

  In addition, by executing the progress crack detection method with a program that runs a computer, the measurement process can be executed automatically or semi-automatically according to the instructions of the computer, and it can be performed correctly and quickly without relying on the judgment of the flaw detector. Measurement is possible with certainty.

  In addition, material noise at a position where the ultrasonic propagation distance is long is reduced in intensity due to ultrasonic propagation attenuation, and the reliability of the material noise information to be compared is reduced. By correcting the height, it is possible to acquire suitable information regarding the progress crack and basic data that enables more accurate grasp and detection of the progress crack.

  Further, by detecting the detected material noise signal and comparing the processing information, more accurate processing can be performed than when noise information is directly processed.

Furthermore, the progress of cracks can be detected more easily and reliably by the image display means by visualization using pseudo color expression corresponding to the difference value.

It is a block diagram showing the configuration of the entire progress crack detection apparatus for using the progress crack detection method according to an embodiment of the present invention. It is one structure figure of the ultrasonic probe of the ultrasonic wave generation means concerning one embodiment of the present invention. It is a flowchart for demonstrating the outline | summary of the whole effect | action which concerns on one Embodiment of this invention. It is explanatory drawing of the production | generation of the material noise based on the foundation of this invention. It is explanatory drawing which shows the production | generation of the material noise which concerns on one Embodiment of this invention, and the relationship between an ultrasonic propagation path. It is a figure explaining the material noise generation system which concerns on one Embodiment of this invention. It is a figure which shows the example of the material noise image produced | generated with the material noise production | generation system which concerns on one Embodiment of this invention. It is a figure which shows the calculation model for simulating a material noise waveform. It is explanatory drawing as an example when simulating a material noise image. It is an example of the waveform of an incident ultrasonic wave when simulating a material noise image. It is an example of a simulated initial material noise image and a material noise image after time. It is an example of the difference image of the simulated material noise image. It is a flowchart which shows the operation | movement step of the crack growth detection method which concerns on one Embodiment of this invention. It is a flowchart which shows in detail the operation | movement of the routine of the comparison process (step SP60) which concerns on the crack progress detection method which concerns on one Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the following, the range necessary for achieving the object of the present invention is schematically shown, and the range necessary for the description of the relevant part of the present invention will be mainly described. According to technology.

  FIG. 1 is a block diagram showing the overall configuration of a progress crack detection apparatus 1 for using a progress crack detection method according to an embodiment of the present invention. As shown in the figure, the progress crack detection apparatus 1 is an ultrasonic generation means (unit) that generates an ultrasonic wave and enters a test object (for example, a structure having a possibility of crack progress or material change). 10. Material noise receiving means (unit) 20 for receiving material noise generated from crystal grains of the object to be inspected when ultrasonic waves are incident; material noise information which is information that can be used for inspection of the received material noise Material noise information processing means (part) 30 to be processed, recording means (part) 40 for storing material noise information as initial material noise information to be compared (initial value), material after time for inspection after time The material noise information comparison processing means (unit) 50 for comparing the noise information with the initial material noise information and producing a comparison result, and the progress crack information for obtaining a judgment information by making a predetermined judgment on the progress crack from the comparison result Constructed comprises a determining means (section) 60. What is used as each of the above means is a routine, a computer in which an algorithm for realizing each function is programmed, the program is stored in an executable format (for example, in a built-in storage area), and stored (not shown) It is realized by an IC chip, a storage medium, a dedicated device, etc. (the same applies to functions / parts / devices indicated as “means” below) Each of these means operates at a predetermined timing according to a command from a control means (for example, CPU: realized by a central processing unit) 90 that controls the operation. The control means (unit) 90 may be configured to operate according to a signal from the operation means (unit) 100.

  In addition to each of the above-described means, the progress crack detection apparatus 1 includes a correction means (part) 70 that corrects the influence of the propagation distance of ultrasonic waves, and / or an image display means (part that displays determination information related to the progress crack on the screen. ) 80 may be included. By additionally providing these functions, it is possible to acquire more accurate information about the progress crack.

  Here, the ultrasonic generation means 10 (typically, realized by an ultrasonic probe including an ultrasonic flaw detector and a piezoelectric element. Hereinafter, “ultrasonic probe 10” or “probe” is used. Is also a device having a function of entering a predetermined ultrasonic wave, and can scan the ultrasonic wave generation means by a human operation or automatic control within a predetermined range (for example, in a range where cracks are expected to occur). .

In the ultrasonic wave generation means 10, it is preferable to optimize the selection of the intensity, waveform, and refraction angle of incident ultrasonic waves. As for the pulse width of the incident ultrasonic wave, a longer one is advantageous from the viewpoint of the amplitude of the material noise, but a shorter one is preferable from the viewpoint of the sharpness of the image (or waveform), so it is optimal in relation to the material to be inspected. Select a value. As the frequency, it is preferable to set the intensity of the material noise high, but an optimum numerical value is adopted in view of the fact that the attenuation is severe when the frequency is high.

As an example of the ultrasonic probe of the ultrasonic wave generation means (unit) 10, for example, one having the structure shown in FIG. 1A can be adopted.

  Returning to FIG. 1, the material noise receiving means (unit) 20 is realized by means of receiving material noise returned from the crystal grains by entering ultrasonic waves, for example, by a combination of a probe and an electronic device. Note that the material noise receiving means may be included in the ultrasonic wave generating means. In other words, the ultrasonic wave generation means (unit) 10 may be capable of both transmitting ultrasonic waves and receiving material noise, and is not limited.

  On the other hand, in order to avoid ultrasonic reverberation noise, a two-element probe that incorporates two transducers and uses one for transmission / reception and the other for reception may be used in a probe that receives ultrasonic waves. Is possible.

  The material noise information processing means (unit) 30 has a function of performing numerical conversion processing or image conversion processing by predetermined arithmetic processing in order to record material noise as information (may be recorded in the recording means (unit) 40). The one having at least one of the functions of detecting the detected material noise signal and extracting the amplitude information is shown.

  The recording means (unit) 40 is a device having a function of storing and storing the converted material noise information (including initial material noise information) by the function of electric and / or magnetic and / or optical / or network. Etc.

  The material noise information comparison processing means (unit) 50 is a device such as a computer having a function of comparing a plurality of material noise information (including initial material noise information and material noise information after aging) by a predetermined arithmetic processing. Realized. The comparison process may be a calculation of a difference in numerical information or a difference between image information and a comparison process as an image signal. The comparison process is performed on the amplitude image signal extracted by the detection process. Things can be used.

  Based on the comparison result, the progress crack information judging means (unit) 60 changes other factors (for example, the material, thickness, temperature, strength, stress, strain, and other external forces of the inspection object) as variables. As (parameters), it is realized by a computer or the like having a function of outputting information related to the progress of cracks (including prediction of progress) by a predetermined calculation process.

  The correction means (unit) 70 is a means for compensating for the decrease in the material noise intensity according to the increase in the propagation distance, and using the material noise intensity of the comparison specimen of the same material as the object to be inspected, the propagation distance-average material noise. A related calibration curve is created and the material noise intensity is corrected.

  Specifically, the correction means (unit) 70 can be realized by a computer or the like equipped with an algorithm having the above functions.

  Furthermore, correction using the material noise of the object to be inspected is possible. Specifically, in an area where there is no defect echo or weld overlay echo, the amplitude is adjusted in such a way as to keep the average intensity of material noise (for example, including the average value, standard deviation, or maximum amplitude) at a constant level. It can be corrected.

The image display means (part) 80 has a function of displaying the judgment result of the progress crack information judgment means (part) 60 and displaying the material noise information processing result. For example, a display (not shown) and information on this display are displayed. This is realized by an output control unit (not shown) that performs the output control. When the determination result is displayed, it may be displayed as electronic information using a predetermined application.
Principle and operation of this embodiment

  Next, the operation, operation, and principle of the present embodiment configured as described above will be described using an example in which B-scope display (cross-section display) in an ultrasonic oblique flaw detection test is used. FIG. 2 is a flowchart for explaining the outline of the overall operation according to the present embodiment. As shown in the figure, first, the ultrasonic probe 10 is brought into contact with the surface of the material 200 to be inspected via a contact medium, and mechanical scanning is performed while ultrasonic waves are incident by the ultrasonic wave generation means (unit) 10. (A101). Ultrasound travels through the material 200 at the refraction angle of the ultrasound probe 10 and generates material noise (A102) at individual grains located along the ultrasound beam path. This is detected by the material noise receiving means (unit) 20 of the ultrasonic probe 10, detected by the material noise information processing means (unit) 30, converted into image data (pixels are intensity-modulated with amplitude), and initial The material noise image is recorded by the recording means (unit) 40.

Next, after a lapse of time, the ultrasonic probe 10 is brought into contact with the surface of the material 200 to be inspected at substantially the same site / position, and mechanically scanned while the ultrasonic waves are incident on the material 200 (A104). The material noise (A105) at the time is detected by the material noise receiving means (part) 20 of the ultrasonic probe 10, detected by the material noise information processing means (part) 30, converted to image data, and after time The material noise image is recorded by the recording means (unit) 40.

Next, the material noise information processing means (part) 30 reads the initial material noise image (information) from the recording means (part) 40, and the material noise information comparison processing means (part) 50 reads the read image (information). And the material noise image (information) after lapse of time, and based on this result, the progress crack information judging means (unit) 60 makes a judgment on the crack progress (A108), obtains information on the progress crack, and In response, the image display means (unit) 80 displays the result as an image.

  FIG. 3 is a diagram for explaining a phenomenon of generation of material noise by the polycrystalline structure 200 which is the basis of the progress crack detection method of the present invention. When the inspection object 200 has a polycrystalline structure like a steel material, the ultrasonic waves incident from the ultrasonic probe 10 are scattered by individual crystal grains and become material noise. Therefore, it is understood that the crystal grains involved in the generation of material noise are within the range covered by the ultrasonic wave and exist along the ultrasonic beam path.

  On the other hand, since the crystal grains are randomly distributed (size, directionality, etc.), the distribution of crystal grains is different no matter which part of the steel material is taken out. Since the material noise signal detected by the ultrasonic probe 10 is a composite of material noise from these individual crystal grains, the distribution state of the crystal grains existing along the propagation path of the ultrasonic waves is indicated. The effect is directly reflected. This means that different material noise signals are received if the ultrasonic propagation path is different, and the same material noise is generated if the ultrasonic wave is propagated to the same path. Of course, it is also a necessary condition that the waveform of the incident ultrasonic wave is the same.

  The invention of the present application is based on this principle, and FIG. 4 is an explanatory diagram showing the relationship between the generation of material noise and the ultrasonic propagation path according to one embodiment. An ultrasonic wave is incident on the inspection object 200 by the ultrasonic probe 10. Before the crack is generated, it is in the state shown in (A), and the incident ultrasonic wave detects the material noise generated by the crystal grains along the path 220. After the occurrence of the crack, the state is as shown in (B), and the material noise generated from the crystal grains along the propagation path 220 changed by the appearance of the crack 210 is detected. Comparing before and after the crack growth, it can be seen that the material noise of the thick line portion of the B path 220 is different. Therefore, by measuring the material noise twice on the same path and comparing them by a method such as taking the difference between the two, the difference between the two is detected, and the phenomenon of changing the ultrasonic propagation path between the two measurements ( It can be known that there was a crack progress etc.).

  In the above description, the steel material has been described as an example of the inspection object. However, any material having a structure / structure serving as an ultrasonic scattering source can be applied to other than steel materials. Examples include a polycrystalline structure, inclusions, precipitates and the like can be a scattering source), FRP (a reinforcing fiber and the like can be a scattering source), concrete (an aggregate and the like can be a scattering source), and the like.

  FIG. 5 is a functional block conceptual diagram showing a functional configuration of the material noise image generation system 2 that generates a material noise image in the progress cracking apparatus 1 according to an embodiment of the present invention and a concept of mechanical scanning. Note that the material noise image generation system follows each step related to the progress crack detection method.

  As shown in the figure, the material noise image generation system 2 extracts a pulser 300 that outputs a predetermined pulse, an amplifier 310 that amplifies the signal detected by the ultrasonic probe 10, and the returned signal as amplitude information. It comprises a detector 320 and an image processor 330 for imaging material noise.

  The pulsar 300 has a function of generating an electric pulse for generating an ultrasonic wave by exciting the ultrasonic probe 10, and is realized by, for example, an electronic circuit. The amplifier 310 includes a function that increases the amplitude of the detected material noise signal, for example, by an electronic circuit. The detector 320 includes, for example, an electronic circuit that realizes a function of extracting amplitude information from the amplified material noise signal. The image processor 330 includes, for example, an electronic circuit that realizes a function of creating a material noise image from the detected material noise signal and probe position information.

  As shown in the figure, when the ultrasonic wave generated by the ultrasonic probe 10 by the pulsar 300 is incident on the inspection object 200, the material noise 230 is returned by the mechanism described above. The material noise 230 is detected by the ultrasonic probe 10, amplified by the amplifier 310, detected by the detector 320, and amplitude information is extracted. These processes are performed while scanning the probe, and two-dimensional material noise is collected and imaged by an image processor. Imaging is achieved by luminance-modulating a pixel at a position determined from the probe position, path, and refraction angle with the material noise amplitude of the path.

  FIG. 6 is an example of a material noise image created by the material noise image generation system 2. The probe is a frequency of 5 MHz, the refraction angle is 45 degrees, and the material is S10C carbon steel. The vertical axis represents depth and the horizontal axis represents horizontal position. Horizontally striped images at the top are reverberation in the probe, not material noise. A cloud-like image distributed under the belt-like image is a material noise image.

Next, the effectiveness and characteristics of the detection method of the progress crack of the present application will be shown by numerical simulation.
FIG. 7 is a diagram showing a calculation simulation method for material noise. The scattering of ultrasonic waves by the crystal grains in the steel material is approximated by a randomly distributed simulated scattering source, and the scattered waves from these scattering sources are returned to the ultrasonic probe and added to become a material noise signal. Using the symbols in FIG. 7, the material noise signal can be calculated by the following equation.

The calculation result g (t, x _i ) represents the waveform of the material noise when the position of the probe is x _i .

Here, FIG. 8 is an explanatory diagram as an example when simulating a material noise image. As shown in FIG. 8, in a region of depth (y) 20 mm to 40 mm and width (x) 0 mm to 70 mm. Scattering sources were randomly distributed, the probe was scanned over the surface (y = 0), material noise g (t, x _i ) was measured every 0.2 mm, and a material noise image was created. The material noise image when there was no crack was 400-1, and the material noise image when a crack with a height of 8 mm was present at a depth of 30 mm was 400-2. Using the waveform shown in FIG. 9 as the waveform of the incident ultrasonic wave, the created material noise image is shown in FIG. 10 with the horizontal axis representing the probe position and the vertical axis representing the depth.

  Although it is difficult to confirm the presence or absence of a crack directly from the material noise image, FIG. 11 shows a difference image between the two material noise images. 400-3 is a difference image with and without a crack of 8 mm in height, and 400-4 is a difference image with and without a crack of 2 mm in height. It can be seen that the presence of cracks clearly appears in the difference image of the material noise image. In addition, there is a crack at the position of the differential image with the shortest path when viewed from the incident direction of the ultrasonic wave, and the width of the differential image (in a cross section perpendicular to the incident direction) represents the size of the crack. I understand.

  Therefore, the method of the present application can obtain information on crack detection and crack size.

  In addition, according to the method of the present embodiment, since the echo from the crack is not used, the amplitude of the echo is not stable like the fatigue crack, and in the worst case, even if the echo is below the noise level If there is a crack progress, the material noise is changed and can be detected.

  In addition, even if the cracks develop even when the weld surplus echo interferes and the echo from the defect is not separated and the defect detection is difficult, in the shadow part of the progress crack as seen from the incident direction of the ultrasonic wave, The progress crack can be detected from the difference in material noise in the region where there is no extra echo.

  Thus, the method of the present application can improve the current state of low reliability in defect detection, which is a drawback of conventional ultrasonic flaw detection, and is considered to play a major role in maintaining the soundness of important structures.

  As described above, it is understood that the progress crack of the present application can be detected and dimensioned by simulation of material noise.

  In the simulation example, comparison of a simple material noise image with a difference image was effective. However, in an actual flaw detection test, various errors entered even when data was collected on the same scanning line, and comparison with a simple difference image was performed. May not be valid. As a countermeasure for the data collection stage in this case, data is collected with a plurality of parallel scanning lines, and these are combined to create a material noise image that can be accurately compared, and in the comparison stage of the material noise image. The accuracy of the comparison between the two material noise images can be increased by extracting the feature points of the material noise pattern and correcting the difference between the two images by pattern matching.

  Next, a detailed operation according to the present application will be described. FIG. 12 is a flowchart showing the operation steps of the crack progress detection method according to an embodiment of the present invention. In addition, in order to implement the crack progress detection method, you may utilize the crack progress detection apparatus 1. FIG.

Ultrasonic waves are incident on the inspection object 200 by the ultrasonic wave generation means 10 (SP10), and the material noise reception means 20 receives the material noise 230 returned from the inside of the inspection object (SP20). The state of the predetermined material noise 230 received is checked, and if it is inappropriate data, the data is re-acquired (SP30). If necessary, the fluctuation of the noise level due to the propagation distance or local sensitivity reduction is corrected. (SP40). Such processing data is processed by the material noise information processing means (part) 30 (SP50) as initial material noise information and recorded in the recording means (part) 40 (SP60). If material noise information already exists after the passage of time (regardless of whether it has been recorded or not), the process proceeds to the next process. If not, the process from SP20 to SP60 is looped.

If there is initial material noise information (if it is recorded in the recording means (part) 40, it will be called from the recording means (part) 40) and post-aging material noise information. The material noise information is compared with the material noise information comparison processing means (unit) 50 (SP70). After the comparison process, information on the progress of the crack portion 210 can be obtained by determining from the comparison result by the progress crack information determining means (unit) 60 (SP80).

  FIG. 13 is a flowchart showing in detail a routine operation related to the comparison process (SP60) in the crack progress detection method of one embodiment of the present invention. Note that the noise image generation system 2 may be used to realize the comparison process.

  As shown in the figure, as described above, the material noise receiving means (unit) 20 can detect the material noise signal and convert it into amplitude information for imaging the material noise (SP200). This process reduces the amount of data to be handled, lowers the required level of positional accuracy during image comparison, and facilitates comparison work for crack detection.

  The processed material noise signal obtains the position information of the probe obtained from the material noise receiving means (unit) 20 and performs imaging (SP210). Correction for making the fluctuation of the noise level uniform can be performed on the obtained material noise image. (SP220).

  Next, a feature amount image can be created and used if necessary for comparison of material noise images. This is effective when crack detection / evaluation using a simple difference image is difficult due to various errors.

  Further, pattern matching can be performed as necessary. In the creation of a difference image, when the creation accuracy of a difference image is lowered due to an error in the position signal and affects crack detection, the position error can be corrected by pattern matching to prevent a drop in crack detection evaluation ability.

  As described above in detail, according to one embodiment of the present invention, the material noise that has been the object of avoiding the influence as much as possible in the flaw detection test is effectively used, and the difference between before and after the crack propagation is calculated. Since the degree of progress is detected by obtaining, it is possible to effectively detect the progress crack. Although a stationary crack is not detected, a really dangerous crack (a crack in progress) is detected, which can greatly contribute to ensuring the safety of the structure.

In addition, since the image is generated by using the detected ultrasonic signal that has been detected and the pixels are luminance-modulated and displayed, the difference image can be displayed in grayscale or pseudo color. As a result, in addition to the mechanical mathematical processing, a human can also visually recognize it with the naked eye, and the safety can be layered.

Moreover, since material noise is recorded, it can be considered that the state of the flaw detection equipment is always checked. Since the state in which the sensitivity is locally lowered (due to lack of anti-catalytic substance, etc.) can be confirmed as an image, it can be used as an index for the reliability of ultrasonic measurement, and the reliability can be improved.

Further, since the sensitivity setting of the flaw detector is performed by setting the average material noise to a constant level, the sensitivity setting is easy.

In addition, about the progress crack detection program which makes a computer perform the progress crack detection method, it can employ | adopt suitably in the range which does not deviate from the main point of this invention including methods other than the method which concerns on FIG.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, pixels can be directly modulated with brightness using the detected ultrasound signal, but in this case, the raw ultrasound signal has a short period, so the amount of data increases and the location of data collection is highly accurate. I think it is necessary to solve the problems that accompany the transformation.

  Further, the above is merely an example of an embodiment for realizing the technical idea according to the present invention, and the technical idea according to the present invention can be applied to other embodiments. is there. For example, in the above description, the idea of using material noise as a medium has been described as an example. However, the present invention, in principle, takes a difference between a physical quantity returned from an inspection object and a physical quantity after a lapse of a certain time, and the principle Therefore, this difference can be visualized whatever the physical quantity can be measured. This makes it possible to select physical quantities suitable for measurement according to the material properties and measurement environment, and not only nondestructive inspection of progress cracks but also the progress of abnormal situations beyond the visible range such as deterioration due to deterioration. Secure discovery more reliably.

  Furthermore, even if the apparatus, method, and system produced using the present invention are listed and commercialized as a secondary product, the value of the present invention is not reduced at all.

  According to the present invention, regarding the physical quantity returned from the inspection object, the difference between the physical quantity after a lapse of a certain time is taken, and in principle, whatever the physical quantity can be measured, By visualizing the difference, not only non-destructive inspection of progress cracks, but also detection of progress beyond the visible range by the naked eye, such as alteration due to deterioration, is possible. Therefore, not only buildings such as ships, bridges, and nuclear facilities, but also chemical plants, construction, civil engineering (dams, etc.), space industry, etc. Has great potential to be widely used and applied.

DESCRIPTION OF SYMBOLS 1 ... Progress crack detection apparatus, 2 ... Material noise image generation system, 10 ... Ultrasonic wave generation means (part) (ultrasonic probe), 20 ... Material noise reception means (part), 30 ... Material noise information processing means ( Part), 40 ... storage part (recording means), 50 ... material noise information comparison processing means (part), 60 ... progress crack information judgment means (part), 90 ... control means (part), 100 ... operation means (part) 200 ... Inspection material, 220 ... Ultrasound, 230 ... Material noise, 300 ... Pulsar, 310 ... Amplifier, 320 ... Detector, 330 ... Image processor, 400-1 ... Example of initial material noise image, 400-2 ... Example of material noise image after time, 400-3 ... Example of difference image of material noise, 400-4 ... Example of difference image of material noise

Claims (9)

  The step of moving the ultrasonic wave generation means with respect to the object to be inspected to make the ultrasonic wave incident, the step of receiving the material noise from the object to be inspected, and the step of recording the received material noise as initial material noise information And, after the elapse of time, moving the ultrasonic wave generation means to the inspection object again in the substantially predetermined range and receiving ultrasonic waves, and receiving material noise after aging from the inspection object, A progress crack detection method comprising: comparing the received material noise after time with the initial material noise information as material noise information after time; and obtaining information on the progress crack from the comparison result. The method for detecting a crack in progress according to claim 1, wherein the generation of the material noise is confirmed in the step of receiving the material noise and / or the step of receiving the material noise after the elapse of time.   3. The progress according to claim 1, wherein the step of comparing takes a difference between an initial material noise image as the initial material noise information and an after-time material noise image as the temporal material noise information. Crack detection method.   In the step of taking the difference, the respective feature points of the initial material noise image and the material noise image after the lapse of time are obtained, and pattern matching at the time of superimposing the images is obtained using each feature point. The method for detecting a crack in progress according to claim 3.  5. A progress crack detection program that causes a computer to execute each step according to the progress crack detection method according to claim 1.   Ultrasonic wave generation means for making ultrasonic waves incident on the inspection object, material noise reception means for receiving material noise from the inspection object, and the material noise when the ultrasonic wave generation means is moved within a predetermined range Material noise information processing means for processing material noise received by the receiving means as material noise information, recording means for recording the processing result of the material noise information processing means as initial material noise information, and the inspection again after a lapse of time Material noise information comparison processing means for comparing material noise information after time obtained by performing the same measurement and processing on an object with the initial material noise information called from the recording means, and this material noise information comparison processing A progress crack detection apparatus comprising: progress crack information determination means for obtaining information on progress cracks from a comparison result of means.   The progress crack detection apparatus according to claim 6, further comprising a correction unit that corrects an influence of a propagation distance of the ultrasonic wave incident on the inspection object.   The material noise information processing means detects the detected material noise signal to extract amplitude information, and the material noise information comparison processing means converts the initial material noise information after the detection processing and the material noise signal after time into an amplitude image signal. The progress crack detection device according to claim 6, characterized in that:   9. The image display means for displaying the judgment result of the progress crack information judgment means, and at least the processing result of the material noise information processing means is also displayed by the image display means. The progress crack detection apparatus according to claim 1.

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