JP6216136B2 - Damage length measurement system and damage length measurement method - Google Patents

Description

  The present invention installs a vibrator and a vibration detection sensor on a measurement object, measures the arrival time of vibration propagating from the vibrator to each vibration detection sensor via the measurement object, and arrives when there is no damage. The present invention relates to a damage length measuring system and a damage length measuring method for measuring the length of damage based on a delay time from time.

  2. Description of the Related Art Conventionally, in structures such as airplanes that require weight reduction, a long reinforcing member called a stringer is bonded to a surface of a plate member (base material) having a relatively large area called a skin panel, or a reinforcing part is integrated. Molding is performed to increase the rigidity. In such a structure, there is a possibility that the reinforcing member is gradually peeled off from the end due to an impact or the like. For example, in a product that requires high reliability such as an airplane, such peeling (this is referred to as damage in this specification). Needs to be discovered before it progresses. For this reason, a technique for measuring the damage length (peeling length) of an object to be measured including a base material and a reinforcing member is becoming important, and various measurement methods have been proposed as methods for measuring the damage length.

For example, Patent Document 1 describes an invention of a measurement method using a plurality of FBG (Fiber Bragg Grating) optical fiber sensors.
In the invention of Patent Document 1, as shown in FIG. 7, a vibrator 3 made of a piezo element or the like is installed on the surface of a plate-like member 1. Further, a plurality of vibration detection sensors 4, 5, and 6 such as FBG optical fiber sensors are installed in the member 2 bonded to the surface of the member 1 with an adhesive along the propagation direction of vibration. Then, a vibration is applied to the base material by vibrating the vibrator, and the arrival time of vibration propagating from the vibrator to the vibration detection sensor via the object to be measured is measured by the measuring device 7.

  First, the arrival time is measured as an initial state measurement with respect to an object that is not damaged, and the arrival time of the vibration is recorded and held. Next, as an actual measurement, an oscillator and a plurality of vibration detection sensors are installed at the same position in principle for an object having the same structure in which only the presence or absence of damage is unknown, and arrival times are measured respectively. Then, the delay time of each sensor from the arrival time when there is no damage is calculated, and the length of damage is calculated based on the delay time difference between the initial state and actual measurement in each sensor.

JP 2011-185921 A

In the measurement method described in Patent Document 1, in most cases, a vibration waveform having a clear peak as shown in FIG. However, it has been found that a vibration waveform with an unclear peak is sometimes observed as shown in FIG.
In the measurement method of Patent Document 1, when a vibration waveform with an unclear peak is observed as shown in FIG. 8 (b), it is difficult to measure the distance, and there is no damage or considerable progress due to an erroneous measurement result. There is also a risk that it will be judged.

  The present invention has been made in view of the above problems, and provides a damage length measurement system and a damage length measurement method capable of measuring the damage length of an object to be measured with high reliability and high accuracy. The purpose is to do.

The invention according to claim 1 for solving the above-described problems is
A vibrator for applying ultrasonic vibration to an object to be measured in which a second member is bonded or bonded to the surface of the first member ;
A vibration detection sensor for detecting a vibration wave oscillated from the vibrator and propagating through the object to be measured;
An arithmetic processing unit that controls the oscillation of the vibrator, performs arithmetic processing on a detection signal of the vibration detection sensor, and analyzes a vibration wave detected by each vibration detection sensor, and the first member on the surface of the first member A damage length measurement system that measures the length of peeling from the end of two members as the damage length,
Two or more vibrators or two or more vibration detection sensors are vibrated so that the vibrator and the vibration detection sensor can obtain three or more types of vibration receiving results having different propagation paths without moving the installation positions of the vibrator and the vibration detection sensor. Arranged side by side in the direction orthogonal to the propagation direction,
The vibrator is installed on the surface of the first member, the vibration detection sensor is installed on the surface of the second member,
Two or more vibration detection sensors are arranged side by side in a direction orthogonal to the direction of peeling generated from the end of the second member,
The arithmetic processing unit calculates arrival times of maximum peaks of three or more types of vibration waves detected by two or more vibration detection sensors,
The damage length is calculated based on the calculated arrival time of 3 or more and the arrival time obtained by measurement on the object without damage,
An average value of the calculated three or more damage lengths is obtained, a damage length deviating from the average value by a predetermined value or more is discarded, and a damage length to be output is determined based on the remaining damage length. It is a thing.
According to the present invention, the damage length is determined based on three or more types of vibration waveforms with different propagation paths, so that a highly accurate damage length measurement value can be obtained, for example, by calculating an average value.
In addition, by discarding the damage length that deviates from the average value by a predetermined value or more as described above, it is possible to prevent the calculation of vibration waveforms with unclear peaks, and to increase the damage length with higher accuracy. Can be measured.

Preferably, the two vibrators and the two vibration detection sensors are arranged side by side in a direction orthogonal to the vibration propagation direction,
The arithmetic processing unit includes:
The two vibrators are sequentially driven and controlled to apply ultrasonic vibration to the object to be measured, and vibration waves propagating through the object to be measured are detected by the two vibration detection sensors, respectively. The corresponding four arrival times are calculated.
By arranging two vibrators and two vibration detection sensors side by side in a direction orthogonal to the vibration propagation direction, four types of vibration waveforms with different propagation paths can be measured, so three or more vibrators are provided. Measurement results can be obtained in a shorter time than when the vibrator is vibrated in three or more times. Further, the damage length can be measured with higher accuracy than in the case of providing one vibrator and three vibration detection sensors.

Here, the object to be measured includes a first member having a flat or curved surface and a second member bonded or bonded to the surface of the first member,
The vibrator may be installed at a predetermined portion of the first member in parallel with the end surface of the second member, and the vibration detection sensor may be installed along the end of the second member.
Thereby, the peeling length of the second member from the first member can be measured with high accuracy.

In addition, other inventions of the present application are:
A vibrator for applying ultrasonic vibration to a measurement object formed by bonding or bonding a second member to the surface of the first member, and a vibration detection sensor for detecting a vibration wave oscillated from the vibrator and propagating through the measurement object And two or more vibrators are arranged side by side in a direction orthogonal to the vibration propagation direction,
An arithmetic processing unit that controls oscillation of the vibrator, performs arithmetic processing on a detection signal of the vibration detection sensor, and analyzes a vibration wave detected by each vibration detection sensor ; and the second member on the surface of the first member A damage length measurement method in a damage length measurement system that measures the length of peeling from the end of the substrate as the damage length,
The vibrator is installed on the surface of the first member, the vibration detection sensor is installed on the surface of the second member,
Two or more vibration detection sensors are arranged side by side in a direction orthogonal to the direction of peeling generated from the end of the second member,
The arithmetic processing unit includes:
For the object to be measured without damage, the two or more vibrators are sequentially vibrated to apply ultrasonic vibration to the object to be measured, and the vibration wave propagating through the object to be measured is detected by the vibration detection sensor, The arrival time of the maximum peak of each vibration wave detected by the vibration detection sensor is calculated and stored in the storage means as the arrival time of the initial state,
For the object to be measured for the presence or absence of damage, sequentially vibrate the two or more vibrators to apply ultrasonic vibration to the object to be measured.
A vibration wave propagating through the object to be measured is detected by the vibration detection sensor, and the arrival time of the maximum peak of each vibration wave detected by the vibration detection sensor is calculated.
Calculate the damage length based on the time obtained by subtracting the arrival time of the initial state read from the storage means from the calculated arrival times,
An average value of a plurality of calculated damage lengths is obtained, damage lengths deviating from the average value by a predetermined value or more are discarded, and the damage length to be output is determined based on the remaining damage length. Is.

According to the damage length measuring method as described above, the damage length can be calculated based on two or more vibration waveforms having different propagation paths. For example, the damage length is measured with high accuracy by calculating an average value. be able to. In addition, since two or more vibrators are vibrated while being shifted in time and a propagating vibration wave is detected by the vibration detection sensor, even if the number of vibration detection sensors is one, for example, two or more different propagation paths By measuring the vibration waveform, the damage length can be measured with high accuracy.
In addition, by discarding the damage length that deviates from the average value by a predetermined value or more as described above, it is possible to prevent the calculation of vibration waveforms with unclear peaks, and to increase the damage length with higher accuracy. Can be measured.

  In other words, according to the present invention, there is an effect that the damage length (peeling length) of the object to be measured can be measured with high reliability and high accuracy.

(A) is explanatory drawing which shows the structural example of the to-be-measured object and damage length measurement system which concerns on one Embodiment of this invention, (B) is a top view which shows an example of the layout of a vibrator | oscillator and a sensor. It is a flowchart which shows the procedure of the process in the damage length measurement system which concerns on one Embodiment of this invention. (A)-(C) is a wave form diagram which shows the example of the vibration waveform detected by the vibration detection sensor, respectively, and analyzed with the measuring device. It is a wave form diagram which shows an example of the vibration waveform detected by the vibration detection sensor and analyzed with the measuring device. (A) is a diagram in which all damage length values measured by the damage length measurement system of the embodiment are plotted in relation to the measurement values obtained by the A-scan test, and (B) is obtained by measurement. It is the figure which plotted the value of the remaining damage length remove | excluding the value of the damage length discarded by the majority vote from the value of damage length. (A), (B) is a top view which shows the other example of the layout of a vibrator | oscillator and a sensor, respectively. It is a block diagram which shows the example of 1 structure of the conventional damage length measurement system. It is a wave form diagram which shows an example of the vibration waveform measured in the conventional damage length measurement system.

Hereinafter, a configuration and a measurement method of a damage length measurement system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is an explanatory diagram showing the configuration of the damage length measurement system of the present embodiment, and FIG. 1B is a plan view of the part of the object to be measured shown in FIG. First, the configuration of the damage length measurement system will be described.
The object to be measured in the damage length measurement system of the present embodiment has a second member 12 smaller than the first member 11 on the surface of a flat or curved plate-like first member 11 having a relatively large area. They are joined by bonding or integral molding.

In the example of the damage length measurement system of the present embodiment, two vibrators 21 a and 21 b are arranged on the surface of the plate-like first member 11 as shown in FIG. Are arranged side by side at a position slightly away from the edge E, and fixed by an adhesive.
Further, the second member 12 bonded or bonded to the surface of the first member 11 has two vibration detection sensors 22a and 22b at the ends thereof along the direction of the edge E (the vertical direction in FIG. 1B). They are also installed side by side and fixed with an adhesive. The vibration detection sensors 22a and 22b function as vibration receiving elements.

The vibration detection sensors 22a and 22b have a predetermined distance from each other and are installed at positions on the inner side by a predetermined distance from both side portions of the second member 12, respectively. Furthermore, the center line of the vibrator 21a and the center line of the vibration detection sensor 22a are aligned, and the center line of the vibrator 21b and the center line of the vibration detection sensor 22b are aligned.
In this embodiment, the direction in which the vibrator 21a (21b) and the vibration detection sensor 22a (22b) are arranged is referred to as a vibration propagation direction, and the direction in which the vibration detection sensors 22a and 22b are arranged is referred to as a direction orthogonal to the vibration propagation direction. . In addition, the substantial detection part G of the vibration detection sensors 22a and 22b installed on the second member 12 is a part of several millimeters (for example, 1.5 mm) from the tip, that is, the edge E of the second member 12. Thereby, the damage (peeling) beyond the length of the sensor portion S can be detected with high accuracy.

  The vibrators 21a and 21b apply ultrasonic vibration to the object to be measured. In this embodiment, PZT (lead zirconate titanate), which is a kind of piezoelectric ceramic that generates vibration by the piezoelectric effect, is used as the vibrator. A PZT actuator is used. The vibrators 21a and 21b are configured to generate A0 mode Lamb waves. The Lamb wave also has an S0 mode, and an Lamb wave in the S0 mode may be used.

Moreover, although the Lamb wave is used in this embodiment, it is not limited to the Lamb wave, and it is also possible to use an SH wave. The vibrators 21a and 21b are not limited to PZT actuators, and may be other piezoelectric elements.
On the other hand, FBG (fiber Bragg grating) optical fiber sensors are used for the vibration detection sensors 22a and 22b. The FBG sensor may be a wire or tape. FIG. 1 shows an example in which a tape-like FBG sensor is used.

The damage length measurement system of this embodiment amplifies the pulse generation circuits 23a and 23b and the pulse signals generated by the pulse generation circuits 23a and 23b, and applies a tone burst wave voltage of a predetermined frequency to the vibrators 21a and 21b. Are provided with amplifiers 24a and 24b for vibrating. The pulse generation circuits 23a and 23b are configured to generate pulses having a frequency corresponding to the frequency of the vibration desired to be generated by the vibrators 21a and 21b.
In addition, the damage length measurement system includes light sources 25a and 25b that enter laser light of a predetermined wavelength into FBG sensors that are vibration detection sensors 22a and 22b, and a circulator 26a that separates reflected light returning from the tip of the optical fiber. , 26b.

  Furthermore, the damage length measurement system includes light receiving elements 27a and 27b that convert the reflected light separated by the circulators 26a and 26b into electric signals, and a waveform analysis device 28 that analyzes the received waveform. The pulse generation circuits 23a and 23b and the light sources 25a and 25b are driven and controlled, and a signal indicating the analysis result from the waveform analyzer 28 is received to calculate the damage length (peeling length) and display it. An arithmetic and control unit 29 for displaying on the device 30 is provided. The display 30 is composed of a CRT or a liquid crystal display. Instead of outputting the measured value to the display device 30, it may be output to a printer.

  The waveform analyzer 28 performs wavelet transform on the detection signal of the Lamb wave received by the receiving elements (22a, 22b), and measures the place where the wavelet coefficient is maximum as the peak of the received wave, that is, the Lamb wave arrival time. The conversion method is not limited to the wavelet transform, and may be another conversion method (for example, Hilbert transform). The arithmetic and control unit 29 calculates the damage length based on the measurement result (Lamb wave arrival time), the attachment positions of the vibrator and sensor, and the Lamb wave group velocity. In addition, the arithmetic and control unit 29 determines the damage length by majority processing from the damage lengths (measured values) calculated for each of the plurality of measurement results (ram wave arrival times) by the plurality of vibration detection sensors 22a and 22b. The damage length is determined and displayed on the display 30.

  The waveform analysis device 28 and the arithmetic control device 29 can be constituted by a CPU, a ROM that stores programs executed by the CPU, a calculation formula, and the like, a RAM that provides a work area, and the like. In FIG. 1, the waveform analysis device 28 and the arithmetic control device 29 are separate devices, but may be configured as a single device. In this specification, a combination of the waveform analysis device 28 and the calculation control device 29 is referred to as a calculation processing device. The arithmetic processing unit can be composed of one computer or workstation.

  The frequency of the drive pulse generated by the pulse generation circuits 23a and 23b is arbitrary, but it can be set to 50 kHz to 150 kHz, for example. The voltage applied to the vibrators 21a and 21b is, for example, a signal obtained by multiplying a sine wave for three periods by a Hamming window function. Here, the signal obtained by multiplying the sine wave by the Hamming window means a waveform signal in which the height of the central mountain is higher than the heights of the two peaks before and after the sine waveform having three peaks. Such a waveform may be obtained by changing the pulse width of the drive pulse output from the pulse generation circuits 23a and 23b, or may be obtained by controlling the gains of the amplifiers 24a and 24b. The vibration waveform applied to the first member 11 is not limited to three cycles, and may be one cycle, two cycles, or four cycles or more.

Next, the procedure of the damage length measurement method in the damage length measurement system will be described with reference to the flowchart of FIG.
The damage length measurement method according to the present embodiment includes the initial state measurement of FIG. 2A and the actual measurement process of FIG. 2B. First, the initial state measurement including steps S1 to S5 is executed. The initial state measurement is a process of measuring a sound structure having no damage (peeling) and recording the arrival time of the maximum peak of the vibration wave propagating through the sound structure as an initial state measurement value. The healthy structure has the same structure as the above-described object to be measured in which the second member 12 is bonded or bonded to the surface of the first member 11 and has no damage.

In the initial state measurement of FIG. 2A, first, the arithmetic and control unit 29 drives and controls the pulse generation circuit 23a (or 23b) to generate tone burst wave vibrations for three cycles by the vibrator 21a (or 21b). Let At the same time, the light sources 25a and 25b are caused to emit light and the laser light is incident on the FBG optical fibers of the vibration detection sensors 22a and 22b (step S1).
Then, the reflected light changed according to the pressure change caused by the vibration received by each vibration detection sensor 22a, 22b is converted into an electrical signal by the light receiving elements 27a, 27b and supplied to the analysis device 28 for waveform analysis ( Processing step S2).

  Specifically, when the vibration detection sensors 22a and 22b receive vibrations from the vibrators in step S2, the characteristics (wavelengths) of the reflected light change according to the strain changes accompanying the vibrations, so that the light receiving elements 27a and 27b The output voltage also changes. The change in the output voltage value of the light receiving elements 27a and 27b is digitized as waveform data by the analyzing device 28. If this is visualized, a waveform as shown in FIG. 3 or 4 is obtained.

Next, the arithmetic and control unit 29 obtains the maximum peak in each received waveform by calculation (step S3). The calculation method is not particularly limited. For example, the maximum peak can be obtained by performing wavelet transform or the like on the received waveform data.
Subsequently, the arithmetic and control unit 29 determines the time when the maximum peak of the received wave is detected from the measurement start time as the Lamb wave arrival time, and records and saves it in the internal memory or the like (step S4).

Thereafter, it is determined whether or not driving of all the vibrators has been completed (step S5). Here, if it is determined that driving of all the vibrators has not been completed (step S5; No), the process returns to step S1 to drive the other vibrator 21b (or 21a) to generate sine wave vibration for three cycles. generate. Then, the waveforms received by the vibration detection sensors 22a and 22b are analyzed, the time when the maximum peak of the received waves is detected is determined as the Lamb wave arrival time, and is recorded and stored in an internal memory or the like. Therefore, in the damage length measurement system of this embodiment, the four Lamb wave arrival time values measured and determined as described above are stored as initial state measurement values.
The initial state measurement is thus completed.

Next, actual measurement processing including steps S6 to S12 in FIG.
In the actual measurement process, the damage length measurement system of the present embodiment measures the damage of the object to be measured that has the same structure as the sound structure whose initial state measurement value is recorded as described above and whose damage is unknown. .
First, the vibrators 21a and 21b and the vibration detection sensors 22a and 22b are installed at the same positions as those in the initial state measurement, and the processes of steps S6 to S10 are performed on the measurement object having the same structure.

The processing in steps S6 to S10 in FIG. 2B is the same as the processing in steps S1 to S5 in the initial state measurement in FIG. 2A, and the four Lamb wave arrival time values are measured values as described above. Remembered. Although detailed description of the procedure is omitted, when the object to be measured has damage (peeling), the arrival time stored in the memory in step S9 corresponds to the damage length.
3A to 3C and FIG. 4 show examples of a received waveform when a damaged object to be measured is measured. In each figure, the received waveforms of four sensors are superimposed and displayed. In FIGS. 3A to 3C, the waveform peak positions are shifted from 50 μs, 100 μs, and 150 μs, respectively, because the damage lengths are different. When the length of damage is different, the arrival time to the sensor is also different due to the Lamb wave wrapping around the damaged portion D as indicated by a broken line R in FIG. As a result, waveforms as shown in FIGS. 3A to 3C and FIG. 4 are measured according to the length of damage.

When the four Lamb wave arrival time values are stored in the memory, the process proceeds to step S11. In step S11, the arithmetic and control unit 29 subtracts the arrival time stored in the memory by the initial state measurement from the arrival time stored in the memory in step S9, the distance between the transducer and the sensor, and the Lamb wave group. The damage length is calculated based on the speed.
For example, when the sensor 22a receives a Lamb wave from the vibrator 21a and when a Lamb wave is received from the vibrator 21b, the propagation distance to the sensor is different. The measurement value of the length is slightly shifted. However, since the deviation can be predicted, in the calculation in step S11, when a Lamb wave is received from the vibrator 21b, it may be calculated using a calculation formula having a correction term for correcting the deviation.

Next, the arithmetic and control unit 29 compares the four damage lengths calculated in step S11 and determines the damage length by majority vote (processing step S12). Specifically, an average value of the calculated four damage lengths is obtained, and a value that deviates from the average value by, for example, ± 10 mm or more is discarded, and the average value of the remaining three values or the middle of the three values is discarded. Is determined as an actual measurement of damage length. In the present specification, this is referred to as majority processing.
Thereafter, the damage length determined in the majority process is output as an actual measurement value to the display 30 or the like, and the process ends (step S13). Here, the determination value of ± 10 mm is not limited to this, and is a value that can be arbitrarily set in consideration of various conditions such as the size and material of the measurement object and the distance between the vibrator and the sensor. Yes, it may be determined experimentally so that high measurement accuracy can be obtained as a result.

  A measured value that deviates by ± 10 mm or more from the average value appears because the amplitude is generally small as shown in FIG. 3C, or the position of the maximum peak is determined among the four waveforms as shown in FIG. This is the case when difficult waveforms are included. The present invention avoids the measurement value of the abnormal waveform as described above being discarded as erroneous detection and the measurement value is determined from the remaining waveform, thereby making it impossible to measure or erroneously detect in the conventional measurement system. It has a feature.

Next, a verification result of measurement by the damage length measurement system and measurement method of the present embodiment will be described.
In order to verify the effectiveness of the damage length measurement method of the present invention, the present inventor used a strip-shaped second member made of CFPR as a measured object on a plate-like first member made of CFPR (carbon fiber reinforced plastic). The thing which adhered the member with the adhesive agent was prepared and it was set as the measuring object. In addition, a PZT actuator was attached to the surface of the first member, and an FBG sensor was attached to the surface of the second member with an adhesive. In this verification, a tape-shaped FBG sensor was used and sealant was applied to the sensor surface.

  The lateral width of the second member was 2.5 cm, and the position of the FBG sensor was a portion 5 mm from the straight edge E of the second member. Two vibration detection sensors are installed so that the center line of the sensor is positioned at a predetermined distance (2.5 mm) from both sides of the second member, and the two vibrators are straight lines of the second member. At the position about 2.3 cm away from the edge E, the centers were placed side by side with a distance of 2 cm.

  Further, PZT actuators were used for the vibrators (21a, 21b), and the waves generated by the vibrators were A0 mode Lamb waves obtained by multiplying a sine wave of three periods at a frequency of 100 kHz by a Hamming window.

  Under the above conditions, 29 specimens (objects to be measured) were measured with 230 damage lengths using the damage length measurement system of the above embodiment, and 4 damages per specimen, totaling 920 damage lengths. A measured value was obtained. The specimen was damaged by cracking from the edge E in the adhesive layer (13). In addition, 230 non-destructive inspections (NDI) called A-scan, which is common in the structural inspection of airplanes, performed 230 damages on the 230 specimens (objects to be measured) to obtain 230 measured values. Then, the results obtained by the two measurement methods were compared and verified. The measurement value obtained by the A-scan test is data that is 100% reliable with no erroneous measurement.

FIG. 5A plots all 920 damage length values measured by the damage length measurement system of the above embodiment in relation to the measurement values (NDI actual measurement values) obtained by the A-scan inspection. Is. FIG. 5B shows the remaining damage length values obtained by removing the damage length values discarded by the majority vote from 920 measured by the damage length measurement system of the above embodiment. -Plotted in relation to measured values obtained by scan test.
In the verification test, there were 24 (2.6%) discarded data in 920. The 24 discarded data were all under different conditions, and no discarded data was generated under one condition. In FIG. 5A, the value greatly deviating from the line y = x where y is the vertical axis and x is the horizontal axis corresponds to the measurement value of the damage length discarded in the verification test.

  FIG. 5B also shows lines L + and L− indicating the upper and lower limits of the range of ± 10 mm from the line y = x. Referring to FIG. 5B, the damage length measurement method of the above embodiment is applied to obtain an average value of four damage lengths, and when a value deviating by ± 10 mm or more from the average value is discarded, the remaining values are discarded. It can be seen that all measured values fall within the range of ± 10 mm.

In addition, as described above, in the measurement of 230 conditions by the verification test, there is no case where two or more measurement results (lamb wave arrival time) are erroneously detected (discarded values) at the same time. Was also confirmed.
From the above results, it can be said that the damage length measurement system of the embodiment has sufficient reliability and can stably detect damage with high accuracy.

  In the above-described embodiment, the case where there are two vibrators and two vibration detection sensors has been described. However, as shown in FIG. 6A, a 3: 1 relationship is shown, as shown in FIG. Thus, it may be provided so as to have a 1: 3 relationship, or a 3: 2 or 2: 3, 3: 3 relationship. In short, any configuration that can obtain three or more types of measurement values with different propagation paths without changing the positional relationship between the vibrator and the vibration detection sensor is acceptable.

In the above-described embodiment, four measurement values are obtained for one object to be measured, and an average value is obtained. A value that deviates by ± 10 mm or more from the average value is discarded. It is also possible to take the difference, identify what seems to be a false detection from the difference, and discard it. In addition, the damage length is calculated and discarded if it exceeds a predetermined value from the average value of the damage length, but it is deviated from the average value based on the arrival time before calculating the damage length. May be discarded.
Further, in the above embodiment, the damage is assumed to be peeling of the bonded portion or the bonded portion, but damage such as a crack of the object to be measured can be measured in the same manner as described above. In that case, the object to be measured may be a single member.

11 1st member (member used as the base material which comprises a to-be-measured object)
12 Second member (member bonded to base material)
21a, 21b Vibrators 22a, 22b Vibration detection sensor (FBG sensor)

Claims (4)

A vibrator for applying ultrasonic vibration to an object to be measured in which a second member is bonded or bonded to the surface of the first member ;
A vibration detection sensor for detecting a vibration wave oscillated from the vibrator and propagating through the object to be measured;
An arithmetic processing unit that controls the oscillation of the vibrator, performs arithmetic processing on a detection signal of the vibration detection sensor, and analyzes a vibration wave detected by each vibration detection sensor, and the first member on the surface of the first member A damage length measurement system that measures the length of peeling from the end of two members as the damage length,
Two or more vibrators or two or more vibration detection sensors are vibrated so that the vibrator and the vibration detection sensor can obtain three or more types of vibration receiving results having different propagation paths without moving the installation positions of the vibrator and the vibration detection sensor. Arranged side by side in the direction orthogonal to the propagation direction,
The vibrator is installed on the surface of the first member, the vibration detection sensor is installed on the surface of the second member,
Two or more vibration detection sensors are arranged side by side in a direction orthogonal to the direction of peeling generated from the end of the second member,
The arithmetic processing unit calculates arrival times of maximum peaks of three or more types of vibration waves detected by two or more vibration detection sensors,
The damage length is calculated based on the calculated arrival time of 3 or more and the arrival time obtained by measurement on the object without damage,
The average value of the calculated three or more damage lengths is obtained, the damage length deviating from the average value by a predetermined value or more is discarded, and the damage length to be output is determined based on the remaining damage length. Characterized damage length measurement system. Two vibrators and two vibration detection sensors are arranged side by side in a direction orthogonal to the vibration propagation direction,
The arithmetic processing unit includes:
The two vibrators are sequentially driven and controlled to apply ultrasonic vibration to the object to be measured, and vibration waves propagating through the object to be measured are detected by the two vibration detection sensors, respectively. 4. The damage length measurement system according to claim 1 , wherein four corresponding arrival times are calculated. The object to be measured includes a first member having a flat or curved surface and a second member bonded or bonded to the surface of the first member,
The damage length measurement according to claim 1, wherein the vibrator is installed at a predetermined portion of the first member, and the vibration detection sensor is installed along an end portion of the second member. system. A vibrator for applying ultrasonic vibration to a measurement object formed by bonding or bonding a second member to the surface of the first member, and a vibration detection sensor for detecting a vibration wave oscillated from the vibrator and propagating through the measurement object And two or more vibrators are arranged side by side in a direction orthogonal to the vibration propagation direction,
An arithmetic processing unit that controls oscillation of the vibrator, performs arithmetic processing on a detection signal of the vibration detection sensor, and analyzes a vibration wave detected by each vibration detection sensor ; and the second member on the surface of the first member A damage length measurement method in a damage length measurement system that measures the length of peeling from the end of the substrate as the damage length,
The vibrator is installed on the surface of the first member, the vibration detection sensor is installed on the surface of the second member,
Two or more vibration detection sensors are arranged side by side in a direction orthogonal to the direction of peeling generated from the end of the second member,
The arithmetic processing unit includes:
For the object to be measured without damage, the two or more vibrators are sequentially vibrated to apply ultrasonic vibration to the object to be measured, and the vibration wave propagating through the object to be measured is detected by the vibration detection sensor, The arrival time of the maximum peak of each vibration wave detected by the vibration detection sensor is calculated and stored in the storage means as the arrival time of the initial state,
For the object to be measured for the presence or absence of damage, sequentially vibrate the two or more vibrators to apply ultrasonic vibration to the object to be measured.
A vibration wave propagating through the object to be measured is detected by the vibration detection sensor, and the arrival time of the maximum peak of each vibration wave detected by the vibration detection sensor is calculated.
Calculate the damage length based on the time obtained by subtracting the arrival time of the initial state read from the storage means from the calculated arrival times,
An average value of a plurality of calculated damage lengths is obtained, a damage length deviating from the average value by a predetermined value or more is discarded, and a damage length to be output is determined based on the remaining damage length. Damage length measurement method.