JP2013246181A - Abnormality diagnostic method for ultrasonic probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of suitably diagnosing abnormality of an array type ultrasonic probe.SOLUTION: An abnormality diagnostic method for an ultrasonic probe includes: a first step of selecting m vibrators 11 out of n (n>m≥1) vibrators 11, transmitting an ultrasonic wave from the selected vibrators to an object to be measured, and receiving an echo from the object to be measured by the selected vibrators; a second step of relatively scanning the selected vibrators in the array direction of the vibrators 11 with respect to the object to be measured and calculating an effective beam width of the selected vibrators with respect to the object to be measured; a third step of sequentially changing the selected vibrators and alternately repeating the first step and second step; and a fourth step of determining that the selected vibrator having an effective beam width equal to or less than a predetermined threshold is abnormal when any of effective beam widths of the respective selected vibrators obtained in the third step is equal to or less than the predetermined threshold.

Description

  The present invention relates to a method for appropriately diagnosing abnormality of an ultrasonic probe including a plurality of transducers arranged along a certain direction.

  Flaw detection is performed using an ultrasonic probe having a plurality of transducers arranged along a certain direction, and each transducer being fixed to each other (hereinafter referred to as an array-type ultrasonic probe as appropriate). When performing, m (n> m ≧ 1) transducers are selected from n (n ≧ 2) transducers included in the array-type ultrasonic probe, and a material to be inspected is selected from the selected transducers. The ultrasonic wave is transmitted toward the object, and the echo from the material to be inspected is received by the selected vibrator. Then, the echoes received by the respective vibrators constituting the selected vibrator are synthesized, and the material to be inspected is detected using this synthesized waveform. This operation is repeated by sequentially switching the selected transducers. For this reason, it is important to appropriately evaluate the relative sensitivity of each transducer and appropriately adjust the flaw detection sensitivity, which is the amplification degree of the echo signal. Specifically, it is important to adjust the flaw detection sensitivity so that when each echo is received from the same artificial flaw by each transducer, the same echo intensity can be obtained by each transducer.

  The performance evaluation method for this array-type ultrasonic probe is not particularly defined by the JIS standard at present. For this reason, it is common to evaluate the performance in accordance with the JIS standard related to the performance evaluation method for a single-vibrator immersion vertical probe described in Non-Patent Document 1. Specifically, the evaluation method of the frequency response using the surface echo of the flat plate test piece described in Section 7.1 of Non-Patent Document 1, the relative using the surface echo of the flat plate test piece described in Section 7.3 The sensitivity evaluation method, and the beam shape and distance amplitude characteristic evaluation method using the φ4 mm steel ball or φ2.5 mm steel wire described in Section 8.5.1 are used.

  Further, as described above, when performing flaw detection using an array type ultrasonic probe, the selected transducers are sequentially switched. In other words, in flaw detection using an array type ultrasonic probe, flaw detection is performed for each selected transducer. For this reason, as a method for diagnosing abnormalities in an array-type ultrasonic probe, if a predetermined artificial flaw is detected for each selected transducer and the intensity of the resultant composite waveform does not drop below an allowable value, the array-type ultrasonic probe A method of determining that an abnormality such as a failure of the transducer has not occurred in the ultrasonic probe is also implemented.

JIS Z2350 “Performance measurement method of ultrasonic probe”

  However, the present inventors have recognized the problem that it is difficult to appropriately evaluate the performance of the array-type ultrasonic probe by the performance evaluation method based on the above-mentioned JIS standard. Specifically, in the method using the surface echo of the flat plate test piece, it is difficult to appropriately evaluate the relative sensitivity of each transducer as described later, and thus to appropriately adjust the flaw detection sensitivity. Further, in the method using a φ4 mm steel ball or φ2.5 mm steel wire, although evaluation of relative sensitivity of each vibrator and adjustment of flaw detection sensitivity are possible as described later, the work of evaluation and adjustment is too complicated. For this reason, it is practically difficult to perform the operation particularly in a state where the array type ultrasonic probe is attached to the inspection line. Furthermore, the present inventors have also recognized the problem that the abnormality of the array-type ultrasonic probe cannot be sufficiently detected only by monitoring the decrease in the intensity of the composite waveform as in the above-described abnormality diagnosis method.

  The above-described problem is not limited to the array-type ultrasonic probe, and includes a plurality of transducers arranged along a certain direction, such as an ultrasonic probe in which a plurality of transducers of one transducer are arranged. This is a problem that can also occur in an ultrasonic probe.

  The present invention has been made to solve the above-described problems of the prior art, and appropriately diagnoses abnormalities in an ultrasound probe having a plurality of transducers arranged along a certain direction. It is an object of the present invention to provide a method that can be applied even when the ultrasonic probe is attached to an inspection line.

As a result of intensive studies on a method for appropriately diagnosing an abnormality of an ultrasonic probe including a plurality of transducers arranged along a certain direction, the present inventors have made any of the constituent transducers When a failure occurs in the transducer such as transmission or reception, the effective beam for the measurement target is lower than the decrease in the intensity of the composite waveform of the echo received from the measurement target received by each transducer constituting the selected transducer. It has been found that the reduction in width occurs first. Here, the effective beam width means that the intensity of the synthesized waveform is predetermined in the profile of the intensity of the synthesized waveform of the echo obtained from the measurement target when the selected transducer is scanned relatively along the arrangement direction of the transducers. Means a length of a range that is equal to or greater than (for example, -6 dB when the maximum intensity is 0 dB).
As shown in FIG. 1, when the flaw detection is performed by scanning the ultrasonic probe 100 relatively in the direction orthogonal to the arrangement direction of the transducers 11 (FIG. 1A shows a case where flaw detection is performed on a tubular body. 1 (b) shows a case where a flaw is detected in a plate-like body), and when the above-mentioned effective beam width is excessively reduced, the effective beam width of one selected transducer S1 and the next selected transducer S2 adjacent to this are selected. The effective beam width does not overlap, and the non-overlapping portion becomes an undetected area, and there is a risk of missing a flaw. The same applies to the selected transducer S2 and the selected transducer S3 adjacent thereto.
Since the decrease in the effective beam width occurs before the decrease in the intensity of the echo composite waveform as described above, the present inventors have sufficiently monitored the decrease in the intensity of the echo composite waveform. I found something I could not foresee. Therefore, in order to properly diagnose an abnormality such as a failure of the vibrator constituting each selected vibrator, it is important to determine whether or not this effective beam width is equal to or smaller than a predetermined threshold value. did. The present inventors have completed the present invention based on the above findings.

That is, in order to solve the above-described problem, the present invention is a method for diagnosing abnormality of an ultrasonic probe including n (n ≧ 2) transducers arranged along a certain direction, The following first to fourth steps are included.
(1) First Step m (n> m ≧ 1) transducers are selected from the n transducers, ultrasonic waves are transmitted from the selected transducers to the measurement target, and the selected oscillations are performed. The child receives an echo from the measurement object.
(2) Second Step The selected transducer is scanned relative to the measurement target along the arrangement direction of the transducers, and the effective beam width of the selected transducer with respect to the measurement target is calculated.
(3) Third step The selected transducers are sequentially switched, and the first step and the second step are alternately repeated.
(4) Fourth step When any of the effective beam widths of the selected transducers obtained in the third step is equal to or smaller than a predetermined threshold, the effective beam width is equal to or smaller than the predetermined threshold. It is determined that an abnormality has occurred in the selected vibrator.

  According to such an invention, it is possible to appropriately diagnose abnormality of the ultrasonic probe.

  According to the present invention, it is possible to appropriately diagnose an abnormality of an ultrasonic probe including a plurality of transducers arranged along a certain direction. In particular, an abnormality can be diagnosed even when the ultrasonic probe is attached to the inspection line.

FIG. 1 shows a situation in which flaw detection is performed by relatively scanning an array type ultrasonic probe in a direction orthogonal to the arrangement direction of transducers. FIG. 2 shows an example of the flaw detection sensitivity correction amount required when oblique angle flaw detection is performed using an array type ultrasonic probe. FIG. 3 shows an example of the flaw detection sensitivity correction amount required when receiving the surface echoes of the plate-like body and the tubular body using the array type ultrasonic probe. FIG. 4 shows an example of the flaw detection sensitivity correction amount required when receiving an echo from a φ4 mm steel ball using an array type ultrasonic probe. FIG. 5 shows an example of the flaw detection sensitivity correction amount required when receiving the bottom echoes of the plate-like body and the tubular body using the array-type ultrasonic probe. FIG. 6 is an explanatory diagram for explaining the meaning of the effective beam width. FIG. 7 is a graph showing an example of the relationship between the failure rate of the transducers constituting the selected transducer, the echo intensity received by the selected transducer, and the effective beam width of the selected transducer. FIG. 8 is a graph showing an example of the result of comparing the actual measured value of the effective beam width of the selected transducer with the calculated value by numerical calculation.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings as appropriate.

<Flaw detection sensitivity adjustment method of ultrasonic probe>
The flaw detection sensitivity adjustment method according to the present embodiment is a method for adjusting flaw detection sensitivity (amplification degree of echo signals) of an array-type ultrasonic probe.
FIG. 2 shows an example of the flaw detection sensitivity correction amount required when oblique angle flaw detection is performed using an array type ultrasonic probe. FIG. 2A is an explanatory diagram for explaining an outline of oblique flaw detection, and FIG. 2B shows a flaw detection sensitivity correction amount required for each transducer.
Specifically, as shown in FIG. 2A, notches F1 and F2 are provided on the bottom surface and the surface of the plate-like body P1 having a surface and a bottom surface substantially parallel to each other. The array-type ultrasonic probe 100 is arranged to face the surface of the plate-like body P1 so that the arrangement direction of the transducers 11 (eight of # 1 to # 8) is inclined. Then, ultrasonic waves were transmitted toward the surface of the plate-like body P1 for each transducer # 1 to # 8, and echoes from the notches F1 and F2 were received for each transducer # 1 to # 8. At this time, the plate-like body P1 was scanned in the left-right direction in FIG. 2 so that the echoes from the notches F1 and F2 could be received by the transducers # 1 to # 8.
The flaw detection sensitivity correction amount on the vertical axis in FIG. 2 (b) means the flaw detection sensitivity correction amount required to make the echo intensities received by the transducers # 1 to # 8 substantially equal. For example, if the flaw detection sensitivity correction amount is 6 dB, it means that the flaw detection sensitivity (amplification degree of the echo signal) needs to be about twice that before the correction. As can be seen from FIG. 2B, the distribution characteristics of the echo intensity between the transducers # 1 to # 8 before the flaw detection sensitivity is corrected are the same for the bottom notch F1 and the surface notch F2.

The present inventors compared the evaluation method using the above-mentioned artificial flaw with other evaluation methods. First, a method using a surface echo of a plate-like body in accordance with the above-mentioned JIS standard and a method using a surface (outer surface) echo of a tubular body (outer diameter φ114 mm, wall thickness 7.5 mm) were examined.
FIG. 3 shows an example of the flaw detection sensitivity correction amount required when receiving the surface echoes of the plate-like body and the tubular body using the array type ultrasonic probe. FIG. 3A is an explanatory diagram for explaining the outline of the evaluation test when the surface echo of the plate-like body is used, and FIG. 3B is an explanation for explaining the outline of the evaluation test when the surface echo of the tubular body is used. FIG. 3 (c) shows the flaw detection sensitivity correction amount required for each transducer.
Specifically, when the surface echo of the plate-like body is used, as shown in FIG. 3A, the vibrator 11 (# 1) is applied to the surface of the plate-like body P1 having a surface and a bottom surface substantially parallel to each other. The array-type ultrasonic probe 100 is arranged so as to face each other so that the arrangement directions of (# 8 to # 8) are substantially parallel. Then, ultrasonic waves were transmitted toward the surface of the plate-like body P1 for each transducer # 1 to # 8, and echoes from the surface of the plate-like body P1 were received for each transducer # 1 to # 8.
When the surface echo of the tubular body is used, as shown in FIG. 3B, the arrangement direction of the transducers 11 (eight of # 1 to # 8) is substantially parallel to the axial direction of the tubular body P2. The array-type ultrasonic probe 100 was arranged so as to face. Then, ultrasonic waves were transmitted toward the outer surface of the tubular body P2 for each transducer # 1 to # 8, and echoes from the outer surface of the plate-like body P1 were received for each transducer # 1 to # 8.
The flaw detection sensitivity correction amount on the vertical axis in FIG. 3 (c) has the same meaning as that shown in FIG. 2 (b), and is for making the intensity of echoes received by the transducers # 1 to # 8 substantially equal. This means the amount of flaw detection sensitivity correction required. As can be seen from FIG. 3C, the distribution characteristics of the echo intensity between the transducers # 1 to # 8 before the flaw detection sensitivity is corrected are the same between the plate-like body P1 and the tubular body P2. 3C and FIG. 2B, the echo intensity distribution characteristic shown in FIG. 3C corresponds to the echo intensity distribution characteristic shown in FIG. 2B. do not do. Therefore, even if the flaw detection sensitivity of each transducer # 1 to # 8 is adjusted according to the result shown in FIG. 3C, the echo intensity when the echo from the artificial flaw is received by each transducer # 1 to # 8 is the same. It cannot be made substantially equal, that is, the flaw detection sensitivity cannot be adjusted appropriately.

Next, the present inventors examined a method using an echo from a φ4 mm steel ball described in the JIS standard described above.
FIG. 4 shows an example of the flaw detection sensitivity correction amount required when receiving an echo from a φ4 mm steel ball using an array type ultrasonic probe. FIG. 4A is an explanatory diagram for explaining an outline of an evaluation test in the case of using an echo from a φ4 mm steel ball, and FIG. 4B shows a flaw detection sensitivity correction amount required for each transducer.
Specifically, as shown in FIG. 4A, an array-type ultrasonic probe 100 is disposed opposite to a φ4 mm steel ball B, and the supersonic wave is directed from each transducer # 1 to # 8 toward the φ4 mm steel ball B. Sound waves were transmitted, and echoes from the φ4 mm steel ball B were received by the transducers # 1 to # 8. At this time, either one of the array-type ultrasonic probe 100 or the φ4 mm steel ball B is moved in the horizontal direction of FIG. 4 so that the φ4 mm steel ball B is positioned immediately below the transducer 11 that transmits and receives ultrasonic waves. Scanned.
The flaw detection sensitivity correction amount on the vertical axis in FIG. 4 (b) has the same meaning as that shown in FIG. 2 (b), and is for making the intensity of echoes received by the transducers # 1 to # 8 substantially equal. This means the amount of flaw detection sensitivity correction required. 4B, the echo intensity distribution characteristic shown in FIG. 4B corresponds to the echo intensity distribution characteristic shown in FIG. 2B. Therefore, if the flaw detection sensitivity of each transducer # 1 to # 8 is adjusted according to the result shown in FIG. 4B, the echo intensity when the echo from the artificial flaw is received by each transducer # 1 to # 8 is substantially reduced. Can be equivalent. However, as described above, either the array-type ultrasonic probe 100 or the φ4 mm steel ball B is scanned each time so that the φ4 mm steel ball B is positioned directly below the transducer 11 that transmits and receives ultrasonic waves. Since the evaluation operation is too complicated, it is substantially difficult to perform the operation particularly in a state where the array type ultrasonic probe is attached to the inspection line.

The inventors of the present invention made further studies and studied a method using a bottom echo of a plate-like body and a method using a bottom (inner surface) echo of a tubular body (outer diameter φ114 mm, wall thickness 7.5 mm).
FIG. 5 shows an example of the flaw detection sensitivity correction amount required when receiving the bottom echoes of the plate-like body and the tubular body using the array-type ultrasonic probe. FIG. 5A is an explanatory diagram for explaining the outline of the evaluation test when the bottom echo of the plate-like body is used, and FIG. 5B is an explanation for explaining the outline of the evaluation test when the bottom echo of the tubular body is used. FIG. 5C shows the flaw detection sensitivity correction amount required for each transducer.
Specifically, when the bottom echo of the plate-like body is used, as shown in FIG. 5A, the vibrator 11 (# 1) is applied to the surface of the plate-like body P1 having a surface and a bottom surface substantially parallel to each other. The array-type ultrasonic probe 100 is arranged so as to face each other so that the arrangement directions of (# 8 to # 8) are substantially parallel. Then, ultrasonic waves were transmitted toward the surface of the plate-like body P1 for each transducer # 1 to # 8, and echoes from the bottom surface of the plate-like body P1 were received for each transducer # 1 to # 8.
When the bottom echo of the tubular body is used, as shown in FIG. 5B, the arrangement direction of the transducers 11 (eight of # 1 to # 8) is substantially parallel to the axial direction of the tubular body P2. The array-type ultrasonic probe 100 was arranged so as to face. Then, ultrasonic waves were transmitted toward the outer surface of the tubular body P2 for each transducer # 1 to # 8, and echoes from the inner surface of the plate-like body P1 were received for each transducer # 1 to # 8.
The flaw detection sensitivity correction amount on the vertical axis in FIG. 5 (c) has the same meaning as that shown in FIG. 2 (b), and is used to substantially equalize the intensity of echoes received by the transducers # 1 to # 8. This means the amount of flaw detection sensitivity correction required. As can be seen from FIG. 5C, the distribution characteristics of the echo intensity between the transducers # 1 to # 8 before the flaw detection sensitivity is corrected are the same between the plate-like body P1 and the tubular body P2. 5C and FIG. 2B, the echo intensity distribution characteristic shown in FIG. 5C corresponds to the echo intensity distribution characteristic shown in FIG. 2B. To do. Therefore, if the flaw detection sensitivity of each transducer # 1 to # 8 is adjusted in accordance with the result shown in FIG. 5C, the echo intensity when the echo from the artificial flaw is received by each transducer # 1 to # 8 is substantially reduced. It can be assumed that the detection sensitivity can be adjusted appropriately.

  Based on the above circumstances, the flaw detection sensitivity adjustment method according to the present embodiment is plate-shaped so that the surface of the plate-like body P1 having a surface and a bottom surface substantially parallel to each other and the arrangement direction of the vibrators 11 are substantially parallel. The body P1 is disposed opposite to the array-type ultrasonic probe 100, or the tubular body P2 is arranged so that the axial direction of the tubular body P2 and the arrangement direction of the transducers 11 are substantially parallel. An ultrasonic wave is transmitted from each vibrator 11 toward the surface of the plate-like body P1 or the outer surface of the tubular body P2, and each vibrator 11 sends a bottom surface of the plate-like body P1 or the tubular body P2. Receiving echoes from the inner surface, and adjusting the flaw detection sensitivity (amplification degree of echo signals) of each transducer 11 so that the intensity of the echo received by each transducer 11 is substantially equal. It is characterized by that.

In addition, in the method using the surface echo of the plate-like body P1 conforming to the JIS standard described above or the method using the surface (outer surface) echo of the tubular body P2 (see FIG. 3), the echo intensity before correction is an oblique flaw detection. While the distribution characteristic is not equivalent to the echo intensity before correction in the case of performing (see FIG. 2), the method using the bottom echo of the plate-like body P1 or the method using the bottom (inner surface) echo of the tubular body P2 (see FIG. 5). ), The reason why the echo intensity before correction has a distribution characteristic equivalent to the echo intensity before correction when oblique inspection is performed (see FIG. 2) can be considered as follows.
In a probe in which a plurality of transducers 11 are fixed to each other as in the array-type ultrasonic probe 100 (each transducer 11 is not relatively displaced), the tilt of each transducer 11 is slightly shifted. It is possible that In particular, the greater the number of vibrators 11, the closer it is impossible to make the slopes of the vibrators 11 uniform. Therefore, it is considered that there is a slight deviation in the direction of the ultrasonic wave transmitted from each transducer 11. When oblique angle flaw detection is performed, ultrasonic waves are refracted at the point of incidence on the material to be inspected and propagate inside the material to be inspected. Since the refraction angle varies depending on the incident angle, if there is a deviation in the direction of the ultrasonic wave transmitted from each transducer 11, the direction of the ultrasonic wave that is refracted at the incident point and propagates inside the inspection object. This deviation is expected to increase further. For this reason, it is considered that the distribution characteristic of the echo intensity before correction is greatly varied.
Similarly, in the method using the bottom echo of the plate-like body P1 or the tubular body P2, the direction of the ultrasonic wave is transmitted when the ultrasonic wave transmitted from each transducer 11 propagates inside the plate-like body P1 or the tubular body P2. It is considered that the deviation of the echo intensity increases, and the distribution characteristic of the echo intensity before correction is greatly varied.
On the other hand, in the method using the surface echoes of the plate-like body P1 and the tubular body P2, the ultrasonic wave transmitted from each transducer 11 is echoed before being propagated into the plate-like body P1 and the tubular body P2. Therefore, it is considered that the distribution characteristics of the echo intensity before correction are small in comparison with the case of using the bottom echo.

<Ultrasound probe abnormality diagnosis method>
The abnormality diagnosis method according to the present embodiment is a method for diagnosing abnormality of an array-type ultrasonic probe having n (n ≧ 2) transducers.
At the time of flaw detection using the array-type ultrasonic probe of this embodiment, m (n> m ≧ 1) transducers are selected from the n transducers, and the selected transducers are directed to the measurement target. Then, an ultrasonic wave is transmitted, and an echo from the measurement object is received by the selected vibrator. Then, the echoes received by the transducers constituting the selected transducer are synthesized, and the measurement object is flawed using the synthesized waveform. This operation is repeated by sequentially switching the selected transducers.

The abnormality diagnosis method according to this embodiment is a method of diagnosing an abnormality based on whether or not the effective beam width of the selected transducer with respect to the measurement target is equal to or smaller than a predetermined threshold value.
FIG. 6 is an explanatory diagram for explaining the meaning of the effective beam width.
The graph shown by the solid line in FIG. 6 shows the case where the selected transducer is scanned relatively along the arrangement direction of the transducers (for example, the array-type ultrasonic probe is mechanically scanned (moved) with respect to the measurement target). An example of a profile of echo intensity (intensity of a composite waveform of echoes) obtained from a measurement target obtained when the selected transducer is also scanned) is shown. The effective beam width means a length of a range in which the echo intensity is a predetermined intensity (for example, −6 dB when the maximum intensity is 0 dB) or more in this profile.

FIG. 7 is a graph showing an example of the relationship between the failure rate of the vibrators constituting the selected vibrator, the echo intensity received by the selected vibrator (the intensity of the combined waveform of echoes), and the effective beam width of the selected vibrator. It is.
Specifically, the number of transducers constituting the selected transducer is 16, and the supply of the transmission voltage (pulse signal voltage for transmitting ultrasonic waves from the transducer) to the transducer is stopped, or The failure of the vibrator was simulated by stopping the input of the echo signal received by the vibrator to the waveform synthesis circuit (the circuit that synthesizes the echo signal received by each vibrator).
As a measurement object, a φ4 mm steel ball was used, and the selection vibrator was arranged opposite to the φ4 mm steel ball in the same manner as the configuration shown in FIG. Then, ultrasonic waves were transmitted and received substantially simultaneously from all the vibrators constituting the selected vibrator to the φ4 mm steel ball except the failed vibrator, and the intensity of the composite waveform of the echo was measured. Further, the selected transducer was relatively scanned along the transducer arrangement direction, and a profile of the echo intensity (the intensity of the combined waveform of echoes) similar to that illustrated in FIG. 6 was calculated.
The above operation was repeated by changing the number of failed vibrators.
The echo intensity shown in FIG. 7 means the maximum intensity in the intensity profile of the composite waveform of the echo calculated as described above. The effective beam width shown in FIG. 7 is calculated from the profile calculated as described above.

As shown in FIG. 7, although both the echo intensity and the effective beam width tend to decrease as the number of faulty vibrators increases (the vibrator fault rate increases), the effective beam is lower than the echo intensity. The decrease in width occurs first. In the example shown in FIG. 7, when the vibrator failure rate is 25%, the echo intensity is reduced only by about 2 dB, but the effective beam width is reduced by 6 dB or more.
As described above with reference to FIG. 1, when the effective beam width is excessively decreased, the effective beam width of one selected transducer and the effective beam width of a selected transducer adjacent to the selected transducer do not overlap and do not overlap. The part may become an undetected area, and there is a risk of missing a flaw. As described above, the reduction in the effective beam width occurs prior to the reduction in the echo intensity. Therefore, monitoring the reduction in the echo intensity cannot be sufficiently foreseen. Therefore, in order to appropriately diagnose an abnormality of the array-type ultrasonic probe such as a failure of the transducer constituting each selected transducer, it is determined whether or not the effective beam width is equal to or smaller than a predetermined threshold value. This is very important.

Based on the above circumstances, the abnormality diagnosis method according to the present embodiment is characterized by including the following first to fourth steps.
(1) First Step Among the n transducers, m (n> m ≧ 1) transducers are selected, ultrasonic waves are transmitted from the selected transducers to the measurement target, and the selected transducers The echo from the measurement target is received by.
(2) Second step The selected transducer is scanned relative to the measurement target along the arrangement direction of the transducers, and the effective beam width of the selected transducer with respect to the measurement target is calculated.
(3) Third Step The selected vibrator is sequentially switched, and the first step and the second step are alternately repeated.
(4) Fourth step When any of the effective beam widths of the selected transducers obtained in the third step is equal to or smaller than a predetermined threshold, the effective beam width is equal to or smaller than the predetermined threshold. It is determined that an abnormality has occurred in the selected vibrator.

When the array-type ultrasonic probe is attached to an inspection line for performing ultrasonic inspection of a plate-like body or a tubular body, the first step and the second step are, for example, the following (a) to (c): It is possible to execute by any of the methods.
(A) Remove the array-type ultrasonic probe from the inspection line for performing ultrasonic flaw detection, install it in a water tank equipped with a scanning mechanism, and attach it to the measurement target (for example, φ4 mm steel ball) installed in the water tank. The first step is executed by transmitting / receiving ultrasonic waves toward the target, and the second step is executed by scanning the array type ultrasonic probe along the arrangement direction of the transducers by the scanning mechanism.
(B) With an array type ultrasonic probe attached to an inspection line for performing ultrasonic flaw detection, a material to be inspected (for example, a plate-like body) with an artificial flaw is placed on the inspection line, and the material to be inspected The first step is performed by transmitting and receiving ultrasonic waves toward the artificial flaw of the first, and the array-type ultrasonic probe is scanned relative to the material to be inspected along the arrangement direction of the transducers. Perform two steps.
(C) With the array type ultrasonic probe attached to the inspection line for performing ultrasonic flaw detection, the inspection line is such that the axial direction of the tube with the artificial flaw is substantially parallel to the arrangement direction of the transducers. The first step is executed by transmitting and receiving ultrasonic waves toward the artificial flaws of the tube, and the tube is spirally conveyed in the axial direction, or the tube is rotated in the circumferential direction and the array type ultrasonic probe is rotated. The second step is performed by scanning the contact in the axial direction of the tube.

  However, the method (a) described above is not practical when the array-type ultrasonic probe cannot be easily removed from the inspection line. Further, although the methods (b) and (c) described above do not require the array-type ultrasonic probe to be removed from the inspection line, the array-type ultrasonic probe is used in order to calculate the effective beam width. It takes time and effort to scan.

  Therefore, as a method for calculating the effective beam width relatively easily, for example, an array type ultrasonic probe that is an alternative to an array type ultrasonic probe (diagnostic target ultrasonic probe) that diagnoses an abnormality attached to an inspection line. Prepare an acoustic probe (alternative ultrasonic probe), calculate the effective beam width of this alternative ultrasonic probe outside the inspection line, and use this calculated value to determine the effective beam of the ultrasonic probe to be diagnosed. It is conceivable to calculate (estimate) the width.

That is, a step of transmitting an ultrasonic wave from each transducer included in the diagnostic target ultrasonic probe toward the measurement target, and receiving an echo from the measurement target by each transducer, and a diagnostic target ultrasonic probe; Prepare another alternative ultrasound probe of the same specification, send ultrasonic waves from each transducer included in the alternative ultrasound probe to the measurement target, and receive the measurement target from each transducer Flaw detection sensitivity and / or transmission of each transducer included in the alternative ultrasonic probe so that the echo intensity from the transducer is equivalent to the echo intensity received by each transducer included in the diagnostic target ultrasonic probe It is also possible to estimate the abnormality of the ultrasound probe to be diagnosed by executing the first step to the fourth step with respect to the voltage adjusting step and the adjusted alternative ultrasonic probe.
Here, another alternative ultrasonic probe having the same specifications includes at least n transducers, and the center frequency and the width of the transducers in the arrangement direction are substantially the same as those of the ultrasonic probe to be diagnosed. It means that it is an ultrasonic probe.

  According to the above method, for example, as described above with reference to FIG. 5A, the measurement target is the plate-like body P1, and the dimension of the plate-like body P1 (the diagnostic target ultrasonic probe is provided). If the dimension along the array direction of the transducer) is greater than or equal to the dimension of the ultrasound probe to be diagnosed (dimension along the array direction of the transducer), each transducer included in the ultrasound probe to be diagnosed It is only necessary to transmit ultrasonic waves toward the surface of the plate-like body P1 and receive echoes from the bottom surface of the plate-like body P1 with each transducer. In other words, since the diagnostic target ultrasonic probe is attached to the inspection line and it is not necessary to relatively scan the diagnostic target ultrasonic probe to calculate the effective beam width, the diagnosis is performed. The effective beam width of the target ultrasonic probe can be calculated (estimated) relatively easily.

  In addition, as a method for calculating the effective beam width relatively easily, it may be possible to use numerical calculation using software for analyzing propagation of ultrasonic waves (software for solving a wave equation using a finite element method). Such software is commercially available, and for example, software named “ComWAVE” (registered trademark) manufactured by ITOCHU Techno-Solutions Corporation can be used.

  That is, software for transmitting ultrasonic waves from each transducer included in the array-type ultrasonic probe toward the measurement target and receiving echoes from the measurement target by each transducer, and performing ultrasonic propagation analysis Is used to calculate the intensity of echoes from the measurement target received by each transducer when transmitting ultrasonic waves from the transducers of the array-type ultrasonic probe to the measurement target. Adjusting the parameter corresponding to the flaw detection sensitivity and / or transmission voltage of each transducer in the software so that the calculated value of the intensity of echo received by each transducer and the actual measurement value are equivalent; It is also possible to estimate the abnormality of the array-type ultrasonic probe by executing numerical calculations corresponding to the first step to the fourth step using the adjusted software.

FIG. 8 is a graph showing an example of the result of comparing the actual value of the effective beam width of the selected transducer with the calculated value of the effective beam width by the above numerical calculation.
The actual value of the effective beam width shown in FIG. 8 is measured under the same conditions as described with reference to FIG. The calculated value of the effective beam width is obtained by executing numerical calculations corresponding to the first step and the second step using the software after parameter adjustment.
As shown in FIG. 8, the measured value and the calculated value of the effective beam width are in good agreement, and it can be seen that the abnormality of the array-type ultrasonic probe can be estimated by numerical calculation.

11 ... vibrator 100 ... ultrasonic probe (array type ultrasonic probe)
P1 ... Plate-like body P2 ... Tubular body

Claims (1)

A method for diagnosing abnormalities in an ultrasonic probe comprising n (n ≧ 2) transducers arranged along a certain direction,
Among the n transducers, m (n> m ≧ 1) transducers are selected, ultrasonic waves are transmitted from the selected transducers to the measurement target, and the selected transducers transmit the ultrasonic waves from the measurement target. A first step of receiving an echo of
A second step of scanning the selected transducer relative to the measurement target along the arrangement direction of the transducers and calculating an effective beam width of the selected transducer with respect to the measurement target;
A third step of sequentially switching the selected vibrator and repeating the first step and the second step alternately;
If any of the effective beam widths of the selected transducers obtained in the third step is less than or equal to a predetermined threshold value, the selected transducer having an effective beam width less than or equal to the predetermined threshold value is abnormal. A fourth step to determine that has occurred;
An abnormality diagnosis method for an ultrasonic probe, comprising:

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