JP2018100948A - Vibration test method and vibration test equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine, with higher accuracy, the presence or absence of damage and the like caused by a vibration test.SOLUTION: A vibration test comprises the following steps:, upon conducting a vibration test with respect to a test piece TP, applying vibration to the test piece TP for the purpose of detecting a frequency response characteristic of the test piece TP at a plurality of measurement times, for example, before start of the vibration test and after an end of the vibration test and the like, of the measurement time in a test period in which the vibration test is conducted, and the measurement time before and after the test period (steps S1 and S4); detecting a vibration level of the test piece TP and applied vibration force with respect to the test piece TP when the vibration for detecting the frequency response characteristic is applied to the test piece TP, and normalizing the vibration level with the applied vibration force for each measuring time to detect the frequency response characteristic of the test piece TP (steps S2 and S5); and detecting the presence or absence of damage caused in the test piece TP by the vibration test on the basis of a deviation of the frequency response characteristic (step S6).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vibration test method and a vibration test apparatus.

In general, vibration tests are conducted to verify the safety and durability of parts for transportation equipment such as automobiles and aircraft in advance, and vibration tests are performed according to JIS standards and standards unique to manufacturers of transportation equipment, etc. Has been. The vibration test is performed, for example, by placing a test body on the vibration table, vibrating the vibration table, and vibrating the test body fixed on the vibration table.
Here, as a result of the vibration test, when the appearance of the test specimen is changed, it is understood that the test specimen is damaged by the vibration test. However, when damage or the like due to a vibration test occurs inside the specimen, damage or the like cannot be detected from the appearance. Therefore, it is necessary to analyze the presence or absence of damage inside the specimen.

  By the way, as a method for detecting the presence or absence of damage or the like inside the test body, for example, vibration is applied to the structural laminated material as the test body, and the vibration frequency spectrum is compared with a preset reference vibration frequency spectrum. Thus, a method for determining the presence or absence of adhesion failure (for example, see Patent Document 1), and the natural frequency and the natural vibration peak value of the sound or vibration generated by hitting the inspected product are set in advance. There has been proposed a method of detecting cracks depending on whether or not the product is in a non-defective product determination region (for example, see Patent Document 2).

JP 2009-97890 A JP-A-3-21457

  However, for example, in the detection method described in Patent Document 1, frequency spectra in different test specimens manufactured in the same manufacturing process are compared, but the frequency spectrum is a somewhat manufacturing method in the manufacturing process. It varies depending on the difference. Further, since it is considered that contact failure or the like has an amplitude dependency, the frequency spectrum also changes depending on the magnitude of the excitation force. Therefore, even if a change in the frequency spectrum occurs, it cannot be said that it is due to poor adhesion, and it is determined whether it is due to poor adhesion, a difference in manufacturing process, or other factors. It is difficult. The same applies to the detection method described in Patent Document 2.

  The present invention has been made paying attention to the above-mentioned unsolved problems, and provides a vibration test method and vibration test apparatus capable of more accurately detecting the presence or absence of damage or the like caused by a vibration test. It is an object.

  According to one aspect of the present invention, when a vibration test is performed on a specimen, the frequency response of the specimen is measured at a plurality of measurement points among a time point within the test period for performing the vibration test and a time point before and after the test period. Perform vibration for detecting frequency response characteristics to detect characteristics, detect vibration level of test specimen and excitation force against specimen when vibration for frequency response characteristic detection is performed, At each measurement point, the vibration level is normalized by the excitation force to detect the frequency response characteristics of the specimen, and the vibration test detects the presence or absence of damage caused to the specimen by the vibration test based on the deviation of the frequency response characteristics. A method is provided.

  According to another aspect of the present invention, a vibration test excitation unit that applies vibration for a vibration test to a specimen, and a characteristic detection that applies vibration for frequency response characteristic detection to the specimen. The vibration level detecting unit for detecting the vibration level of the specimen when the vibration is performed by the characteristic detecting vibration unit, and the characteristic detecting vibration unit, and the characteristic detecting vibration unit. Frequency response characteristics of the test specimen by normalizing the vibration level detected by the vibration detection section and the vibration level detected by the vibration detection section. A characteristic calculation unit that detects and stores the frequency response at a plurality of measurement time points within a test period and a time point before and after the test period for performing a vibration test. A vibration test apparatus is provided that performs vibration for characteristic detection.

  According to one embodiment of the present invention, the presence or absence of damage or the like caused by a vibration test can be detected with higher accuracy.

It is a lineblock diagram showing an example of a vibration measuring device in a first embodiment of the present invention. It is a flowchart for demonstrating the operation example of a vibration testing apparatus. It is a block diagram which shows an example of the vibration measuring apparatus in 2nd embodiment. It is a characteristic view which shows an example of the frequency response characteristic based on a vibration level, and the frequency response characteristic based on an acoustic level. It is a block diagram which shows an example of the vibration measuring apparatus in 3rd embodiment. It is a block diagram which shows an example of the vibration measuring apparatus in 4th embodiment. It is a block diagram which shows an example of the vibration measuring apparatus in 5th embodiment. It is a block diagram which shows an example of the vibration measuring apparatus in 6th embodiment. It is another example of a display of the determination result of the presence or absence of damage.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following detailed description, numerous specific specific configurations are set forth in order to provide a thorough understanding of embodiments of the present invention. However, it is apparent that other embodiments can be implemented without being limited to such specific specific configurations. The following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

First, a first embodiment of the present invention will be described.
In the first embodiment, the frequency response characteristic before the vibration test of the test body TP matches the frequency response characteristic after the vibration test depending on whether or not the test body TP is damaged by the vibration test. Therefore, the presence or absence of damage or the like by the vibration test is detected using this relationship.
FIG. 1 is a schematic configuration diagram illustrating an example of a vibration test apparatus 100 according to the first embodiment.
As shown in FIG. 1, the vibration test apparatus 100 includes a vibrator jig 1, a vibrator (vibrator for detecting characteristics, a vibration test vibrator) 2 that vibrates the vibrator jig 1, and , A signal generator 3 for driving and controlling the shaker 2, a load cell (vibration force detection unit) 4 interposed between the shaker 2 and the shaker jig 1, and a shaker jig 1 is input to a vibration sensor (vibration level detection unit) 5 that detects vibration generated in the test body TP fixed to the test body TP that is fixed on 1, and a detection signal of the load cell 4 and a detection signal of the vibration sensor 5 are input. (Fast Fourier Transform) FFT processing device 6 that performs computation processing, a computing device (characteristic computation unit) 7 that computes frequency response characteristics from detection signals of the load cell 4 and the vibration sensor 5 that have been fast Fourier transformed by the FFT computation device 6; Is provided.

The vibrator jig 1 is formed in a table shape and is horizontally supported by the vibrator 2. The vibrator 2 reciprocates the vibrator jig 1 in the vertical direction (vertical direction in FIG. 1) in accordance with the input vibration signal.
The signal generator 3 outputs a vibration test excitation signal for performing a vibration test and a vibration response signal for detecting a frequency response characteristic of the specimen TP to the vibration generator 2. The vibration signal for vibration test is a signal for generating vibration with a desired vibration pattern. The excitation signal for frequency response characteristic detection is a signal whose frequency band is set according to the size and weight of the test body TP. The excitation signal for frequency response characteristic detection is a signal having a constant amplitude and a swept frequency, and is a signal that gives a constant excitation force to the specimen TP or vibrates the specimen TP with a constant acceleration. is there. In general, when the test specimen TP is damaged, the frequency response characteristics before and after the point of damage are different, and the frequency band in which the frequency response characteristics vary differs depending on the size, weight, and damage level of the test specimen TP. For example, when the specimen TP is relatively large, there is a difference in frequency response characteristics before and after the point of damage even at a relatively low frequency, but when the specimen TP is relatively small, damage occurs at a relatively low frequency. Differences in frequency response characteristics are unlikely to occur before and after a certain point, and differences in frequency response characteristics are likely to occur before and after a point of damage if the frequency is relatively high. Therefore, the frequency band for sweeping the excitation signal for detecting the frequency response characteristic is set according to the size of the test body TP, the damage level, and the like.

  The signal generator 3 outputs a vibration test vibration signal to the vibration generator 2 when performing a vibration test of the test body TP. In addition, an excitation signal for detecting frequency response characteristics is output to the vibrator 2 before the start of the vibration test and after the end of the vibration test. That is, when the signal generator 3 performs a vibration test on the test body TP, the signal generator 3 first outputs an excitation signal for detecting the frequency response characteristic to the shaker 2, and then adds an excitation signal for the vibration test. An oscillation signal is output, and then an excitation signal for frequency response characteristic detection is output. “Before starting the vibration test” refers to a time point at which the frequency response characteristic of the specimen TP can be detected at the start time of the vibration test. The term “after the vibration test is completed” refers to a time point at which the frequency response characteristic of the test body TP can be detected when the vibration test is completed.

The excitation signal for detecting the frequency response characteristic desirably has the same signal characteristic before and after the vibration test, but does not necessarily have to be completely coincident. This is because, as described later, when calculating the frequency response function FRF-A before the vibration test and the frequency response function FRF-B after the vibration test, the vibration level detected by the vibration sensor 5 is detected by the load cell 4. This is because the signal is normalized.
As the vibration sensor 5, any sensor capable of detecting a vibration level, such as an accelerometer, a laser displacement meter, or the like, such as vibration acceleration, vibration speed, vibration displacement, or the like can be applied.

  The calculation device 7 includes a storage unit (storage area) 7a and a display unit 7b, and the detection signal of the vibration sensor 5 is detected from the detection signal of the load cell 4 and the detection signal of the vibration sensor 5 which are fast Fourier transformed by the FFT calculation device 6. (That is, the vibration level of the test body TP) is divided by the detection signal of the load cell 4 (that is, the excitation force of the shaker 2 with respect to the shaker jig 1) and normalized before and after the vibration test. As the frequency response characteristics of the test body TP, the frequency response function FRF-A before the vibration test and the frequency response function FRF-B after the vibration test are calculated and stored in the storage unit 7a. Further, the arithmetic unit 7 displays the frequency response function FRF-A before the vibration test and the frequency response function FRF-B after the vibration test in a superimposed manner on the display unit 7b as shown in FIG.

Next, operation | movement of the vibration test apparatus 100 in 1st embodiment is demonstrated with the flowchart of FIG.
First, the test body TP is fixed on the vibrator jig 1, and the vibration sensor 5 is fixed on the test body TP. First, an excitation process for detecting frequency response characteristics before the vibration test is performed (step S1). That is, the signal generator 3 outputs an excitation signal for frequency response characteristic detection, that is, a signal whose amplitude is constant and sweeps the frequency to the vibration generator 2 and applies the frequency response characteristic detection signal to the specimen TP. Shake. The vibration exciter 2 moves the vibration exciter jig 1 up and down according to the input vibration signal, and thereby the specimen TP vibrates up and down according to the vibration signal. The excitation force applied from the vibrator 2 to the vibrator jig 1 at this time is detected by the load cell 4, and the detected signal is Fourier transformed by the FFT arithmetic unit 6 and input to the arithmetic unit 7. Further, the vibration state of the test body TP is detected by the vibration sensor 5, and the detection signal of the vibration sensor 5 is Fourier-transformed by the FFT calculation device 6 and input to the calculation device 7. In the arithmetic unit 7, the detection signal of the vibration sensor 5 is normalized with the detection signal of the load cell 4, the frequency response function FRF-A before the vibration test is calculated (step S2), and the calculation result is stored in the storage unit 7a.

Next, a vibration test is performed on the specimen TP (step S3). That is, the signal generator 3 outputs a vibration test vibration signal to the vibration generator 2, and performs vibration test on the test body TP. Thereby, the vibrator 2 vibrates according to the vibration signal, and vibration is applied to the test body TP through the vibrator jig 1.
During the vibration test, that is, during the test period in which the vibration test is performed, the detection by the vibration sensor 5 and the load cell 4 and the arithmetic processing in the FFT arithmetic unit 6 and the arithmetic unit 7 are not performed.
Subsequently, vibration for detecting frequency response characteristics after the vibration test is performed (step S4). That is, the signal generator 3 outputs a vibration signal for detecting the frequency response characteristic to the vibrator 2 and performs vibration for detecting the frequency response characteristic on the specimen TP. The vibration signal output to the vibrator 2 in step S4 is a signal equivalent to the vibration signal for detecting the frequency response characteristic output in step S1. The vibration for detecting the frequency response characteristic after the vibration test is performed under the same conditions as the vibration for detecting the frequency response characteristic before the vibration test. That is, the excitation force is applied using an excitation signal that generates an equivalent excitation force in an equivalent frequency band. The types and arrangement positions of the vibration sensor 5 and the load cell 4 are also the same.

In the FFT arithmetic unit 6 and the arithmetic unit 7, the frequency response function FRF-B after the vibration test is calculated in the same procedure as the process in step S2, and the calculation result is stored in a predetermined storage area (step S5).
Then, in the calculation device 7, the frequency response function FRF-A before the vibration test calculated in step S2 and the frequency response function FRF-B after the vibration test calculated in step S5 are, for example, as shown in FIG. The display is superimposed (step S6). In the superimposed diagram in FIG. 1, the horizontal axis represents frequency and the vertical axis represents “vibration level / excitation force”.

  Here, when the specimen TP is not damaged by the vibration test, there is no change in the frequency response characteristics before and after the vibration test. Therefore, the frequency response functions FRF-A and FRF-B coincide with each other. Should do. On the other hand, when the specimen TP is damaged by the vibration test, the frequency response characteristics change before and after the vibration test, so that the frequency response functions FRF-A and FRF-B are shifted. Should occur. Therefore, as shown in FIG. 1, whether or not the specimen TP is damaged by the vibration test is detected by detecting whether or not the frequency response functions FRF-A and FRF-B displayed in a superimposed manner are detected. Can be determined.

In general, the greater the damage or the like, the greater the frequency response characteristics change, and the greater the deviation between the frequency response functions FRF-A and FRF-B, the difference between the frequency response functions FRF-A and FRF-B. By detecting the amount of deviation, the degree of damage can be estimated.
Further, the arithmetic device 7 calculates the frequency response functions FRF-A and FRF-B by normalizing the vibration level with the excitation force. Therefore, even if the frequency band and amplitude of the excitation signal are different before and after the vibration test when the vibration for frequency response characteristic detection is performed, before the vibration test. It is possible to reduce the influence of fluctuations in the frequency response characteristics caused by different measurement environments, such as the excitation signal, between the frequency response functions FRF-A and FRF-B.

In addition, since the vibration for detecting the frequency response characteristic before the vibration test and the vibration for detecting the frequency response characteristic after the vibration test are performed under the same conditions, damage to the specimen TP is excluded. It is possible to reduce the occurrence of deviation in the frequency response function due to other factors, and to detect the presence or absence of damage with higher accuracy.
Further, the vibration for detecting the frequency response characteristic with respect to the specimen TP before the vibration test, the vibration for detecting the vibration test with respect to the specimen TP, and the vibration for detecting the frequency response characteristic with respect to the specimen TP after the vibration test are tested. The body TP is continuously performed while being fixed on the vibrator jig 1. Various sensors can be used to suppress the occurrence of damage to the specimen TP due to other factors than the vibration test, and when performing vibration for detecting frequency response characteristics before and after the vibration test. As for the arrangement position, the vibration method for the specimen TP, etc., vibration can be performed under the same conditions. Therefore, it is possible to reduce the influence of the frequency response function due to the influence of the excitation conditions and the arrangement positions of various sensors, and the damage caused to the specimen TP due to the vibration test can be more accurately performed. Can be detected.

  In the first embodiment, one vibration sensor 5 is provided for the test specimen TP, but the number is not limited to one, and a plurality of vibration sensors 5 may be provided at different positions on the test specimen TP. The amount of deviation between the frequency response functions FRF-A and FRF-B increases as the distance from the damaged portion increases. Therefore, by providing a plurality of vibration sensors 5 and comparing the amount of deviation between the frequency response functions FRF-A and FRF-B at the position where each vibration sensor 5 is arranged, the damaged portion can be estimated. That is, it can be estimated that the vicinity of the arrangement position of the vibration sensor 5 having the largest deviation between the frequency response functions FRF-A and FRF-B is a damaged portion. The detection signals of the plurality of vibration sensors 5 may be collected continuously during the vibration for detecting the frequency response characteristics, that is, during the period for performing the vibration for detecting the frequency response characteristics, or During the vibration for detecting the frequency response characteristics, the vibration sensors 5 to be collected may be sequentially switched and collected.

Next, a second embodiment of the present invention will be described.
As shown in FIG. 3, the vibration test apparatus 101 according to the second embodiment includes an acoustic sensor 11 instead of the vibration sensor 5 as a vibration level detection unit in the vibration test apparatus 100 according to the first embodiment. is there. The same parts as those of the vibration test apparatus 100 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the vibration test apparatus 101, the acoustic sensor 11 is disposed, for example, in proximity to the test body TP above the test body TP. The detection signal of the acoustic sensor 11 is Fourier-transformed by the FFT calculation device 6 and input to the calculation device 7. As the acoustic sensor 11, any sensor capable of detecting an acoustic level, such as a microphone, an acoustic intensity, an acoustic particle velocimeter, or the like can be applied.

  In the arithmetic unit 7, the detection signal of the acoustic sensor 11 (that is, the acoustic level of the test body TP) is obtained from the detection signal of the load cell 4 and the detection signal of the acoustic sensor 11 that are fast Fourier transformed by the FFT arithmetic unit 6. The frequency response function FRF-A before the vibration test and the frequency response function FRF-B after the vibration test are normalized by dividing by the detection signal (that is, the vibration force of the vibration generator 2 with respect to the vibration jig 1). Calculate. Moreover, the arithmetic unit 7 displays the frequency response function FRF-A before the vibration test and the frequency response function FRF-B after the vibration test in a superimposed manner as shown in FIG. In the superimposed diagram in FIG. 3, the horizontal axis represents frequency, and the vertical axis represents “acoustic level / excitation force”.

Also in this second embodiment, if no damage or the like occurs in the vibration test, the frequency response characteristics of the sound level are the same before and after the vibration test, and a deviation occurs if damage or the like occurs.
Therefore, also in the second embodiment, the same effect as the first embodiment can be obtained. Further, by providing a plurality of acoustic sensors 11 or using a microphone array, a beam forming microphone, or the like as the acoustic sensor 11, a damaged portion can be estimated.

  Further, the acoustic sensor 11 is not disposed on the test body TP but is disposed in the vicinity of the test body TP without contact. When the vibration sensor 5 is used as in the first embodiment, since the vibration sensor 5 is fixed to the test body TP, the vibration sensor 5 is arranged on the test body TP when the test body TP is small. There is a possibility that the vibration sensor 5 is affected. However, since the acoustic sensor 11 is disposed without contact with the test body TP, the frequency response function can be detected with higher accuracy without being affected by the provision of the acoustic sensor 11, that is, damage Etc. can be determined with higher accuracy.

  FIG. 4 is a characteristic diagram (FIG. 4A) showing a frequency response function before and after the vibration test detected by the vibration test apparatus 100 in the first embodiment, and detected by the vibration test apparatus 101 in the second embodiment. It is a characteristic view (Drawing 4 (b)) showing a frequency response function before and after a vibration test. In FIGS. 4A and 4B, a substrate on which various components such as a capacitor are mounted is used as the test body TP. After the substrate for the test body TP is vibrated to detect the frequency response characteristics before the vibration test, the mounting of any mounting component, for example, the capacitor, on the substrate for the test body TP is disconnected. In this state, vibration for detecting frequency response characteristics after the vibration test was performed. The vibration sensor 5 detects vibration acceleration, and the acoustic sensor 11 detects sound level.

4 (a) and 4 (b), the solid line represents the frequency response characteristic before disconnecting the capacitor from the substrate, and the broken line is the line after forcibly disconnecting the capacitor from the substrate. Represents frequency response characteristics. In FIG. 4A, the horizontal axis represents frequency, and the vertical axis represents vibration acceleration / excitation force. Further, in FIG. 4B, the horizontal axis represents frequency, and the vertical axis represents sound level / excitation force.
When the vibration level of the test body TP is detected by the vibration sensor 5 (FIG. 4A) and when the sound level of the test body TP is detected by the acoustic sensor 11 instead of the vibration sensor 5 (FIG. 4B). In either case, when the excitation frequency is relatively small (for example, about 5200 Hz or less in FIG. 4), the frequency response characteristics match before and after disconnecting the capacitor from the substrate. It can be seen that the frequency response characteristics do not match when the frequency is higher than about 5200 Hz. That is, it can be seen that since the connection of the capacitor to the substrate is cut, the frequency response characteristics change before and after cutting, and the two do not match.

Next, a third embodiment of the present invention will be described.
As shown in FIG. 5, the vibration test apparatus 102 in the third embodiment is further similar to the vibration test apparatus 100 in the first embodiment shown in FIG. The load cell 4 is configured to detect the excitation force by the shaker 21 instead of the shaker (vibration unit for vibration test) 2. Since the other parts are the same, the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.
The vibrator 21 is a vibrator that can perform vibration in a higher frequency range than the vibrator 2. Further, the vibrator 21 is disposed on the specimen TP at a place where a plurality of types of vibration modes can be excited. That is, it is arranged at a portion that becomes an antinode of more vibration frequencies, for example, a portion excluding a portion that becomes a node of the vibration frequency that is on a diagonal line or a symmetrical axis.

In the vibration test apparatus 102, the signal generator 3 outputs an excitation signal for vibration test, and the signal generator 22 outputs an excitation signal for frequency response characteristic detection. The vibrator 21 is fixed to the specimen TP via the load cell 4, and the excitation force of the vibrator 21 is applied to the specimen TP via the load cell 4. The detection signal of the load cell 4 and the detection signal of the vibration sensor 5 are Fourier-transformed by the FFT calculation device 6 and then input to the calculation device 7.
When performing a vibration test, as shown in the flowchart of FIG. 2, first, an excitation process for detecting a frequency response characteristic before the vibration test is performed (step S1). In the vibration test apparatus 102, the signal generator 22 outputs an excitation signal for detecting frequency response characteristics to the vibrator 21. Thereby, the vibration exciter 21 vibrates according to the vibration signal, and the vibration force by the vibration vibrator 21 is applied to the test body TP via the load cell 4. As a result, the test body TP vibrates, and this vibration is detected by the vibration sensor 5 and input to the arithmetic device 7 via the FFT arithmetic device 6. Further, the excitation force from the vibration exciter 21 detected by the load cell 4 is input to the arithmetic device 7 via the FFT arithmetic device 6. In the arithmetic unit 7, the detection signal of the vibration sensor 5 subjected to Fourier transform is normalized with the detection signal of the load cell 4, and the frequency response function FRF-A before the vibration test is calculated (step S2).

Next, a vibration test process is performed (step S3). That is, the signal generator 3 outputs a vibration test vibration signal to the vibration generator 2. Thereby, the vibration exciter 2 vibrates the vibration exciter jig 1 in accordance with the vibration signal for the vibration test, and the vibration exciter 1 applies the vibration force to the specimen TP.
Subsequently, an excitation process for detecting frequency response characteristics after the vibration test is performed (step S4). In the vibration test apparatus 102, the signal generator 22 outputs an excitation signal for detecting frequency response characteristics to the vibrator 21. Thereby, the vibration exciter 21 vibrates according to the vibration signal, the vibration force is applied to the test body TP via the load cell 4, and the detection signal of the load cell 4 and the detection signal of the vibration sensor 5 are converted into the FFT arithmetic unit 6. Is input to the arithmetic unit 7 via.

Then, the frequency response function FRF-B after the vibration test is calculated by the arithmetic unit 7 (step S5), and the frequency response functions FRF-A and FRF-B before and after the vibration test are as shown in FIG. Are superimposed and displayed (step S6).
Here, the vibration test is generally performed in a frequency band of about 0 Hz to about 2.6 kHz or less. On the other hand, when the test specimen TP is damaged, especially when the electronic component mounted on the electronic board is defective in soldering, poor adhesion, small cracks, etc., the excitation signal for detecting the frequency response characteristic has a relatively high frequency. There is a tendency to be detected when the frequency band is about 3 kHz or more and about 8 kHz or less. Further, depending on the performance of the vibration test shaker 2, it may be difficult to vibrate up to a band of 3 kHz or more.

  The vibration test apparatus 102 includes a vibration test shaker 2 and a frequency response characteristic detection shaker 21 that can vibrate at a higher frequency than the vibration test shaker 2. ing. Therefore, by properly using these two vibrators 2 and 21, the specimen TP can be vibrated in a wider frequency band, that is, the presence or absence of damage can be more accurately determined regardless of the size of the specimen TP. Can be determined. In addition, even when the frequency range of vibration that can be generated as the vibrator 2 is relatively low, damage or the like due to a vibration test can be detected with higher accuracy by separately providing a vibrator 21 for frequency response detection. It is possible to easily realize the vibration test apparatus 102 that can be used.

As an excitation signal for detecting frequency response characteristics, a frequency band can be arbitrarily determined, and random excitation, sweep excitation, and the like can be arbitrarily selected. For example, when the component mounted on the test body TP is small, such as an electronic substrate, the upper limit frequency of the vibration signal for detecting the frequency response characteristic can be input up to about 10 kHz, thereby achieving higher accuracy. A frequency response characteristic can be detected.
As described above, the vibration test apparatus 102 according to the third embodiment can obtain the same effects as those of the first embodiment, and can further improve the usability.

Next, a fourth embodiment of the present invention will be described.
As shown in FIG. 6, the vibration test apparatus 103 according to the fourth embodiment includes an acoustic sensor 11 instead of the vibration sensor 5 in the vibration test apparatus 102 according to the third embodiment. The same parts as those of the vibration test apparatus 102 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the vibration test apparatus 103, the acoustic sensor 11 is disposed, for example, in the vicinity of the test body TP above the test body TP3. The detection signal of the acoustic sensor 11 is Fourier-transformed by the FFT calculation device 6 and input to the calculation device 7.

  When performing the vibration test, as in the second embodiment, the vibration for detecting the frequency response characteristic before the vibration test, the vibration for the vibration test, and the vibration for detecting the frequency response characteristic after the vibration test are performed. . Then, during the vibration for frequency response characteristic detection before and after the vibration test, the detection signal of the acoustic sensor 11 (that is, the detection signal of the acoustic sensor 11 (that is, the detection signal of the acoustic sensor 11) is obtained from the detection signal of the load cell 4 and the detection signal of the acoustic sensor 11. The sound level of the specimen TP) is normalized by the detection signal of the load cell 4 (that is, the excitation force of the vibrator 21 on the specimen TP), and the frequency response function FRF-A before the vibration test and the frequency after the vibration test. The response function FRF-B is calculated, and these frequency response functions are superimposed and displayed as shown in FIG. In the superimposed diagram in FIG. 6, the horizontal axis represents frequency, and the vertical axis represents “acoustic level / excitation force”.

In the fourth embodiment, the same operational effects as those of the third embodiment can be obtained, and by providing a plurality of acoustic sensors as the acoustic sensor 11, a damaged portion can be estimated.
In the third embodiment and the fourth embodiment, the case where the vibrator 21 is provided separately from the vibrator 2 for the vibration test has been described as the vibrator for detecting the frequency response characteristics. Regardless of the shaker 21, vibration may be applied by a hammer having a load cell.
Next, a fifth embodiment of the present invention will be described.

As shown in FIG. 7, the vibration test apparatus 104 according to the fifth embodiment is provided with a vibration sensor 31 instead of the load cell 4 as an excitation force detection unit in the vibration test apparatus 102 according to the first embodiment shown in FIG. 1. It is a thing. The same parts as those of the vibration test apparatus 102 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the vibration test apparatus 104, a vibration sensor 31 is provided in the vibrator jig 1 separately from the vibration sensor 5, and detects vertical vibration of the vibrator jig 1. The output signal of the vibration sensor 31 is input to the FFT calculation device 6, subjected to Fourier transform and input to the calculation device 7.
The arithmetic unit 7 performs a fast Fourier transform, a detection signal representing the vibration level of the vibrator jig 1 detected by the vibration sensor 31, and a detection signal representing the vibration level of the specimen TP detected by the vibration sensor 5. Based on the above, the detection signal of the vibration sensor 5 (that is, the vibration level of the test body TP) is divided by the detection signal of the vibration sensor 31 (that is, the vibration level of the vibration jig 1) and normalized to obtain a vibration test. The previous frequency response function FRF-A and the frequency response function FRF-B after the vibration test are calculated. Then, as shown in FIG. 7, these frequency response functions are displayed in a superimposed manner.

In the vibration test apparatus 104 according to the fifth embodiment, when performing a vibration test, first, an excitation signal for detecting a frequency response characteristic corresponding to the size and weight of the test body TP is generated from the signal generator 3 and applied. Based on the vibration level of the vibration jig 1 and the vibration level of the specimen TP, the frequency response function FRF-A before the vibration test is detected.
Next, after performing a vibration test with a desired vibration pattern, an excitation signal for frequency response characteristic detection is again generated from the signal generator 3 to detect the frequency response function FRF-B after the vibration test.
In the fifth embodiment, the same operational effects as those of the first embodiment can be obtained.

Next, a sixth embodiment of the present invention will be described.
As shown in FIG. 8, the vibration test apparatus 105 in the sixth embodiment is different from the vibration test apparatus 104 in the fifth embodiment in that an acoustic sensor 11 is provided instead of the vibration sensor 5 as a vibration level detection unit. . The same parts as those of the vibration test apparatus 104 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the vibration test apparatus 105, the acoustic sensor 11 is disposed, for example, in proximity to the test body TP above the test body TP3. The detection signal of the acoustic sensor 11 is Fourier-transformed by the FFT calculation device 6 and input to the calculation device 7. Further, the detection signal of the vibration sensor 31 provided in the vibrator jig 1 is Fourier transformed by the FFT computing device 6 and input to the computing device 7.

  Then, similarly to the vibration test apparatus 104 in the fifth embodiment, the detection signal of the acoustic sensor 11 (that is, the acoustic signal of the test body TP) is obtained from the detection signal of the vibration sensor 31 and the detection signal of the acoustic sensor 11 subjected to fast Fourier transform. Level) is normalized by the detection signal of the vibration sensor 31 (that is, the vibration level of the shaker jig 1), and the frequency response function FRF-A before the vibration test and the frequency response function FRF-B after the vibration test are calculated. As shown in FIG. 8, these frequency response functions are displayed in a superimposed manner. In the superimposed diagram in FIG. 8, the horizontal axis represents frequency, and the vertical axis represents “acoustic level / excitation force”.

In the sixth embodiment, the same effect as that of the fifth embodiment can be obtained, and a damaged portion can be estimated by providing a plurality of acoustic sensors 11.
In each of the above embodiments, the vibration test and the detection of the frequency response characteristic after the vibration test are performed in the state in which the test body TP is fixed to the vibrator jig 1 when the frequency response characteristic before the vibration test is detected. Do. That is, if the specimen TP is attached or removed before or after the vibration test, the vibration characteristics may change. For example, the vibration characteristics may change only by tightening screws for fixing to the vibrator jig 1. Therefore, after the detection of the frequency characteristic before the vibration test is started, the test body TP is kept fixed to the vibrator jig 1 until the detection of the frequency characteristic after the vibration test is completed.

In each of the above embodiments, the excitation force detected by the load cell 4 may be used when normalizing the detection signal of the vibration level and sound level of the test body TP, and the test body detected by the vibration sensor 31 may be used. Vibration acceleration equivalent to the excitation force that vibrates the TP may be used.
Further, in each of the above embodiments, which of the method of detecting the vibration level by the vibration sensor 5 and the method of detecting the sound level by the acoustic sensor 11 is adopted is, for example, the size of the test body TP, etc. What is necessary is just to judge according to the characteristic of the test body TP. That is, in the case of a comparatively small test body TP, there is a possibility of being affected by the vibration sensor 5 arranged on the test body TP, so it is preferable to use the acoustic sensor 11 that can be detected in a non-contact manner. In some cases.

Further, in each of the embodiments described above, the case of vibrating in the vertical direction has been described. Each vibration sensor may be arranged at a position where vibration in the vibration direction can be detected.
Moreover, in each said embodiment, although the case where the acoustic sensor was arrange | positioned above the test body TP was demonstrated, it is not restricted to this, It can arrange | position in arbitrary positions.
In each of the above embodiments, the case where the frequency response characteristics before and after the vibration test are displayed in a superimposed manner has been described, but the present invention is not limited to this. For example, a plurality of acoustic sensors 11 are provided. The surface with the test body TP is divided into a plurality of regions, and the acoustic sensor 11 is arranged at the center position of each divided region, and measurement is performed by exciting at a single frequency. For example, the frequency at the peak value of the amplitude obtained by the frequency response is selected, and the sine wave is excited at that frequency. By performing this test before and after the vibration test and taking the difference between the measurement results before and after, the amount of deviation of each point can be obtained. Then, the shift amount is displayed in a map corresponding to the position where the acoustic sensor 11 is arranged, for example, by changing the display color according to the size of the shift amount. By doing so, the acoustic sensor 11 may be visually identified in the vicinity of which acoustic sensor 11 is likely to be damaged based on the magnitude of the shift amount. FIG. 9 shows a map displayed by this measurement method. The side surface of the test body TP is divided into four regions, and the upper surface is divided into two regions. The acoustic sensor 11 is arranged in each region, and measurement is performed to obtain a deviation amount and map display is performed.

Although the amount of deviation is shown in FIG. 9, the magnitude of vibration in the vibration test can be displayed as a map.
Further, in each of the above embodiments, the case where the vibration for frequency response characteristic detection is performed before the vibration test and after the vibration test has been described, but the present invention is not limited to this, and within the test period in which the vibration test is performed. The frequency response function may be detected by performing vibration for detecting frequency response characteristics at a plurality of measurement points of time and before and after the test period.
That is, in each of the above embodiments, by collecting the detection signals of the vibration sensor 5 or the acoustic sensor 11 at a desired timing during the test period for performing the vibration test, the frequency response function is detected in parallel with the vibration test, The presence or absence of damage may be determined. Further, for example, during the test period in which the vibration test is performed, the vibration test is temporarily stopped and the vibration for detecting the frequency response characteristic is performed, and the detection signal of the vibration sensor 5 or the acoustic sensor 11 is used as the detection signal. By detecting the frequency response function based on this, the presence or absence of damage may be determined even during the test period of the vibration test.

By determining whether or not there is damage during the vibration test period in this way, for example, if the subsequent vibration test is stopped when the damage is detected, unnecessary vibration tests can be avoided. be able to. The vibration for frequency response characteristic detection that is performed once the vibration test is stopped during the test period of the vibration test may be performed, for example, at a constant cycle or at an arbitrary timing.
In order to detect the frequency response characteristics at a relatively early time after the start of the vibration test, that is, when the frequency response characteristics of the specimen TP can be regarded as the same as the frequency response characteristics at the start of the vibration test. The frequency response function may be calculated by collecting the detection signals of the various sensors and used as the frequency response function before the vibration test. Further, at the time near the end of the vibration test, that is, when the frequency response characteristic of the specimen TP can be regarded as the same as the frequency response characteristic at the end of the vibration test, various sensors for detecting the frequency response characteristic The detection signals may be collected and a frequency response function may be calculated and used as the frequency response function after the vibration test.

  It should be noted that the scope of the present invention is not limited to the illustrated and described exemplary embodiments, but includes all embodiments that provide the same effects as those intended by the present invention. Further, the scope of the invention can be defined by any desired combination of specific features among all the disclosed features.

DESCRIPTION OF SYMBOLS 1 Exciter jig 2 Exciter 3 Signal generator 4 Load cell 5 Vibration sensor 6 FFT operation device 7 Arithmetic device 11 Acoustic sensor 21 Exciter 22 Signal generator 31 Vibration sensor 100-105 Vibration test device

Claims (8)

When performing a vibration test on a specimen, a frequency response characteristic of the specimen is detected at a plurality of measurement points of a time point within a test period for performing the vibration test and a time point before and after the test period. Excitation for frequency response characteristics detection
When the vibration for detecting the frequency response characteristic is performed, the vibration level of the test body and the excitation force against the test body are detected,
At each measurement time point, the vibration level is normalized with the excitation force to detect the frequency response characteristic of the test specimen, and damage caused to the test specimen by the vibration test based on the deviation of the frequency response characteristic is detected. A vibration test method characterized by detecting presence or absence. Separately from the vibration unit that performs vibration test for the test body, it is used for frequency response characteristic detection that performs vibration in a higher frequency band than the vibration unit that performs vibration test. A vibration unit is provided,
The vibration test method according to claim 1, wherein the vibration for detecting the frequency response characteristic is performed by the vibration unit for detecting the frequency response characteristic.   The one of the measurement time points is a time point before the start of the vibration test, and the other one of the measurement time points is a time point after the end of the vibration test. Vibration test method.   The vibration test method according to claim 1, wherein the measurement time points include a plurality of time points during the test period.   The vibration test method according to any one of claims 1 to 4, wherein the vibration level is detected by a vibration sensor or an acoustic sensor.   The vibration test method according to any one of claims 1 to 5, wherein the excitation force is detected by a load cell or a vibration sensor. A vibration test excitation unit that applies vibration test to the specimen;
A characteristic detecting vibration unit for performing vibration for frequency response characteristic detection on the specimen;
A vibration level detection unit for detecting a vibration level of the specimen when vibration is being performed by the characteristic detection excitation unit;
An excitation force detection unit that detects an excitation force applied to the specimen when excitation is performed by the characteristic detection excitation unit;
A characteristic calculator that normalizes the vibration level detected by the vibration level detector with the excitation force detected by the excitation force detector and detects a frequency response characteristic of the specimen and stores it in a storage area;
With
The characteristic detecting vibration unit performs the vibration for detecting the frequency response characteristic at a plurality of measurement points of a time point within a test period for performing the vibration test and a time point before and after the test period. Vibration test equipment.   The vibration test apparatus according to claim 7, wherein the vibration test vibration unit also serves as the characteristic detection vibration unit.

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