JP7629809B2 - Impact vibration test device, impact vibration test method, and impact vibration test program - Google Patents

Description

This disclosure relates to an impact vibration test device, an impact vibration test method, and an impact vibration test program.

As a test device for applying impact acceleration to a test specimen, for example, an impact vibration test device is known that includes a vibration table on which the test specimen is placed and a drive unit that drives the vibration table to apply acceleration to the test specimen (see, for example, Patent Document 1). In the impact vibration test device, for example, if the acceleration of a pulse wave that starts from zero and has only a component in a certain direction is specified as an excitation wave, if vibration is applied according to this waveform, the excitation table will continue to be displaced in one direction. For this reason, in practice, the excitation table is driven so that a compensation excitation wave that includes a waveform having a value in the excitation direction and is adjusted so that the sum of the time integral values of the shock pulse wave and the waveform in the opposite direction to the excitation direction is zero is applied to the test specimen.

JP 2020-153870 A

In impact vibration testing, the feasibility of the test is evaluated in two ways: either by determining whether the vibration was generated according to the time history waveform of the vibration acceleration, or by determining whether the floor response spectrum of the vibration table during vibration satisfies the target value.

When a compensating excitation wave, including an impact pulse wave and an adjustment excitation wave in the opposite direction to the excitation wave, is applied to the test specimen, the floor response spectrum may have a lower value on the long-period side compared to the floor response spectrum when the acceleration of the time history waveform of only the impact pulse wave is applied to the test specimen. In this way, if the value of the floor response spectrum on the long-period side does not reach the target value, the test will be conducted without sufficient acceleration being applied to the test specimen.

To address this issue, it is possible to apply to the test specimen an acceleration that is amplified uniformly over the entire time period of the original time history waveform, but this would result in excessive vibration because the value of the short-period floor response spectrum in the floor response spectrum of the vibration table would also rise. Also, in order to compensate for the drop in the long-period side of the floor response spectrum, it is possible to perform a separate test in which an acceleration that only has long-period components is applied to the test specimen, but this would increase the number of tests and the test time.

The present disclosure has been made in consideration of the above, and aims to provide an impact vibration test device, an impact vibration test method, and an impact vibration test program that are capable of appropriately and efficiently performing a test in which an impact acceleration is applied to a test specimen.

The impact vibration test device according to the present disclosure includes a vibration table on which a test specimen is placed, a drive unit that drives the vibration table to apply acceleration to the test specimen, and a control unit that controls the drive unit so that an acceleration represented by a time history waveform including an impact pulse wave and an adjusted excitation wave that is placed before and after the impact pulse wave in time is applied to the test specimen, and the control unit generates the time history waveform so that the sum of the time integrals of the impact pulse wave and the adjusted excitation wave is zero and the period of the adjusted excitation wave is 10 times or more the period of the impact pulse wave.

The impact vibration test method according to the present disclosure includes placing a test specimen on a vibration table, generating a time history waveform including an impact pulse wave and an adjusted excitation wave that is placed before and after the impact pulse wave in time, such that the sum of the time integrals of the impact pulse wave and the adjusted excitation wave is zero and the period of the adjusted excitation wave is 10 times or more the period of the impact pulse wave, and driving the vibration table so that the acceleration indicated by the generated time history waveform is applied to the test specimen.

The impact vibration test program according to the present disclosure includes an impact pulse wave and an adjusted excitation wave that is placed before and after the impact pulse wave in time, and causes a computer to execute a process of generating a time history waveform in which the sum of the time integrals of the impact pulse wave and the adjusted excitation wave is zero and the period of the adjusted excitation wave is 10 times or more the period of the impact pulse wave, and a process of driving a vibration table on which a test specimen is placed so that the acceleration indicated by the generated time history waveform is applied to the test specimen.

This disclosure makes it possible to perform tests that apply impact acceleration to a test specimen appropriately and efficiently.

FIG. 1 is a diagram showing a schematic diagram of an example of an impact vibration testing device according to the present embodiment. FIG. 2 is a graph showing an example of a time history waveform. FIG. 3 is a flowchart showing an example of an impact vibration test method according to this embodiment. FIG. 4 is a graph showing a time history waveform input to the drive unit. FIG. 5 is a graph showing an example of a floor response spectrum when a time history waveform is input.

Below, an embodiment of an impact vibration test device, an impact vibration test method, and an impact vibration test program according to the present disclosure will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are replaceable and easy for a person skilled in the art, or those that are substantially the same.

Figure 1 is a schematic diagram showing an example of an impact vibration test device according to this embodiment. As shown in Figure 1, the impact vibration test device 100 includes a vibration table 10, a drive unit 20, and a control unit 30.

The vibration table 10 places the test object 40 on it. The test object 40 is an evaluation target for evaluating suitability for vibration. The test object 40 may be, for example, a nuclear facility, but is not limited to this, and may be, for example, equipment or structures for aircraft, equipment or structures for automobiles, or other equipment or structures.

The driving unit 20 drives the vibration table 10 so that acceleration (impact acceleration) is applied to the test body 40. The driving unit 20 has a driving source (not shown), such as an electromagnetic coil, and a transmission mechanism (not shown) that transmits the driving force generated by the driving source. The driving unit 20 drives the vibration table 10 based on the control of the control unit 30.

The control unit 30 controls the driving by the driving unit 20. The control unit 30 has a processing device such as a CPU (Central Processing Unit) and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The control unit 30 has a generation unit 31, a driving control unit 32, and a storage unit 33.

The generating unit 31 generates a time history waveform that drives the driving unit 20. FIG. 2 is a graph showing an example of a time history waveform. The horizontal axis of FIG. 2 indicates time, and the vertical axis indicates acceleration. On the vertical axis of FIG. 2, the positive direction of acceleration is the vibration direction applied to the test body 40. The negative direction of acceleration is the direction opposite to the vibration direction applied to the test body.

2, the time history waveform 50 includes an impact pulse wave 51 and adjusted excitation waves 52 and 53. The impact pulse wave 51 is set to a predetermined period T1 (hereinafter referred to as impact period T1) in a time series. The impact pulse wave 51 is a trapezoidal waveform having an increase portion 51a, a maintenance portion 51b, and a decrease portion 51c. The increase portion 51a is a portion where the acceleration increases from 0 over time. The maintenance portion 51b is a portion where the acceleration maintains a constant state after the increase portion 51a. The decrease portion 51c is a portion where the acceleration decreases to 0 over time after the maintenance portion 51b. The length of each period and the magnitude of the acceleration in the maintenance portion 51b of the impact pulse wave 51 are set according to, for example, the test body 40.

The adjusted excitation wave 52 is placed in a period T2 (hereinafter referred to as the adjusted period T2) that precedes the shock pulse wave 51. The adjusted excitation wave 52 is set so as to be continuous with the shock pulse wave 51. The adjusted excitation wave 52 has an acceleration portion 52a where the acceleration is a positive value, and a deceleration portion 52b where the acceleration is a negative value. Note that the adjusted excitation wave 52 does not necessarily have to have an acceleration portion 52a.

The adjusted excitation wave 53 is placed in a period T3 (hereinafter referred to as the adjusted period T3) that is later in time than the shock pulse wave 51. The adjusted excitation wave 53 is set so as to be continuous with the shock pulse wave 51. The adjusted excitation wave 53 has an acceleration portion 53a where the acceleration is a positive value, and a deceleration portion 53b where the acceleration is a negative value. Note that the adjusted excitation wave 53 does not necessarily have to have an acceleration portion 53a.

The generating unit 31 generates the time history waveform 50 so that the sum of the time integrals of the shock pulse wave 51 and the adjusted excitation waves 52 and 53 is 0. In other words, the generating unit 31 generates the time history waveform 50 so that the area of the region S1 where the acceleration is a positive value is equal to the area of the region S2 where the acceleration is a negative value.

The generating unit 31 also generates the time history waveform 50 so that the adjustment period T2 of the adjusted excitation wave 52 and the adjustment period T3 of the adjusted excitation wave 53 are each 10 times or more longer than the impact period T1. The generating unit 31 generates the time history waveform 50 so that it is symmetrical on the time axis.

The drive control unit 32 controls the operation of the drive unit 20 so that the acceleration shown in the time history waveform 50 generated by the generation unit 31 is applied to the test body 40.

The storage unit 33 stores various information. The storage unit 33 has storage such as a hard disk drive or a solid state drive. Note that an external storage medium such as a removable disk may be used as the storage unit 33. The storage unit 33 stores programs, data, etc. used for processing in the generation unit 31 and the drive control unit 32.

The memory unit 33 stores an impact vibration test program that causes a computer to execute a process of generating a time history waveform 50 including an impact pulse wave 51 and adjusted excitation waves 52, 53 that are respectively arranged before and after the impact pulse wave 51 in time, in which the sum of the time integral values of the impact pulse wave 51 and the adjusted excitation waves 52, 53 is zero and the adjustment periods T2, T3 are 10 times or more longer than the impact period T1, and a process of driving the excitation table 10 on which the test body 40 is placed so that the acceleration indicated by the generated time history waveform 50 is applied to the test body 40.

Next, an example of the impact vibration test method according to this embodiment will be described. The impact vibration test method according to this embodiment uses the impact vibration test device described above. FIG. 3 is a flowchart showing an example of the impact vibration test method according to this embodiment. As shown in FIG. 3, the impact vibration test method according to this embodiment includes a placement step S10, a waveform generation step S20, and a drive control step S30.

In the placement step S10, the test object 40 is placed on the vibration table 10.

In the waveform generation step S20, the generation unit 31 of the control unit 30 generates a time history waveform 50 of the acceleration applied to the test body 40.

In the drive control step S30, the drive control unit 32 of the control unit 30 controls the drive of the drive unit 20 so that the acceleration shown in the time history waveform 50 generated by the generation unit 31 is applied to the test body 40.

In the drive control step S30, the drive unit 20 drives the vibration table 10 under the control of the drive control unit 32. By driving the drive unit 20, the vibration table 10 applies an acceleration (impact acceleration) shown by the time history waveform 50 to the test body 40.

Figure 4 is a graph showing an example of a time history waveform. Figure 4 shows a time history waveform (solid line portion) 50 according to this embodiment generated by the generation unit 31, and a time history waveform (dashed line portion) 50A according to a comparative example. In the graph of Figure 4, the horizontal axis represents time, and the vertical axis represents acceleration.

The time history waveform 50 according to this embodiment and the time history waveform 50A according to the comparative example are similar in terms of the impact periods T1, T5 in which the shock pulse waves 51, 55 are arranged, and their magnitudes. On the other hand, in the time history waveform 50 according to this embodiment, the adjustment periods T2, T3 of the adjusted excitation waves 52, 53 are longer than the adjustment periods T6, T7 of the adjusted excitation waves 56, 57 of the time history waveform 50A according to the comparative example. In addition, the absolute values of the adjusted excitation waves 52, 53 of the time history waveform 50 are smaller than the absolute values of the adjusted excitation waves 56, 57 of the time history waveform 50A so that the sum of the time integral values of the shock pulse wave 51 and the adjusted excitation waves 52, 53 is 0.

Figure 5 is a graph showing an example of the floor response spectrum of the vibration table when the acceleration shown in the time history waveform is applied to the test body 40. Figure 5 shows a floor response spectrum (solid line portion) 70 for the time history waveform 50, a floor response spectrum (dashed line portion; hereafter referred to as the comparison spectrum) 70A for the time history waveform 50A of the comparative example, and a floor response spectrum (dash-dotted line portion; hereafter referred to as the target spectrum) 71 corresponding to the time history waveform of only the shock pulse wave 51 (55). In the graph of Figure 5, the horizontal axis shows the period in logarithm, and the vertical axis shows the acceleration.

As shown in FIG. 5, the comparison spectrum 70A has smaller acceleration values on the long-period side (right side) than the target spectrum 71. The floor response spectrum 70 according to this embodiment has smaller acceleration values on the high-frequency side than the target spectrum 71, but larger acceleration values than the comparison spectrum 70A. In other words, the floor response spectrum 70 has a more suppressed drop in the high-frequency side than the comparison spectrum 70A, compared to the target spectrum 71. In this way, by lengthening the adjustment periods T2 and T3 of the adjusted excitation waves 52 and 53, the drop in acceleration on the high-frequency side is improved in the floor response spectrum 70.

For example, in a test in which an impact acceleration is applied to the test specimen 40, if the floor response spectrum 70 obtained in the test exceeds the target spectrum 71 over the entire periodic band, the test can be recognized as a valid test. For this reason, the adjustment periods T2 and T3 can be set so that the floor response spectrum 70 exceeds the target spectrum 71. In this case, the adjustment periods T2 and T3 can be set together to a value 10 or more times the impact period T1 of the shock pulse wave 51.

It can be estimated that the longer the adjustment periods T2 and T3, the more the drop in acceleration on the high frequency side in the floor response spectrum 70 is suppressed. The adjustment periods T2 and T3 can be set appropriately within the range allowed by, for example, the constraints of the test time.

Therefore, by setting the combined adjustment periods T2 and T3 to a value 10 times or more the impact period T1 within the range allowed by the constraints of the test time, the effectiveness of the test can be ensured, and the test can be performed efficiently by preventing the test time from becoming too long. In addition to setting the combined adjustment periods T2 and T3 to a value 10 times or more the impact period T1, the acceleration amplitude level may be increased over the entire range of the acceleration time history waveform.

As described above, the impact vibration test device 100 according to this embodiment includes a vibration table 10 on which the test object 40 is placed, a drive unit 20 that drives the vibration table 10 to apply acceleration to the test object 40, and a control unit 30 that controls the drive unit 20 so that an acceleration indicated by a time history waveform 50 including an impact pulse wave 51 and adjusted excitation waves 52 and 53 that are respectively placed before and after the impact pulse wave 51 in time is applied to the test object 40, and the control unit 30 generates the time history waveform 50 so that the sum of the time integral values of the impact pulse wave 51 and the adjusted excitation waves 52 and 53 is 0 and the adjustment periods T2 and T3 are 10 times or more longer than the impact period T1.

The impact vibration test method according to this embodiment includes placing the test object 40 on the vibration table 10, generating a time history waveform 50 including an impact pulse wave 51 and adjusted vibration waves 52 and 53 that are respectively arranged before and after the impact pulse wave 51 in time, in which the sum of the time integrals of the impact pulse wave 51 and the adjusted vibration waves 52 and 53 is zero and the adjustment periods T2 and T3 are 10 times or more longer than the impact period T1, and driving the vibration table 10 so that the acceleration indicated by the generated time history waveform 50 is applied to the test object 40.

The impact vibration test program according to this embodiment includes an impact pulse wave 51 and adjusted excitation waves 52, 53 that are respectively placed before and after the impact pulse wave 51 in time, and causes a computer to execute a process of generating a time history waveform 50 in which the sum of the time integrals of the impact pulse wave 51 and the adjusted excitation waves 52, 53 is zero and the adjustment periods T2, T3 are 10 times or more longer than the impact period T1, and a process of driving the vibration table 10 on which the test body 40 is placed so that the acceleration indicated by the generated time history waveform 50 is applied to the test body 40.

According to this configuration, by making the adjustment periods T2 and T3 10 times or more longer than the impact period T1, it is possible to suppress the drop in acceleration on the long-period side in the floor response spectrum 70, and to prevent the test time from becoming too long. This makes it possible to perform a test in which acceleration is applied to the test body 40 appropriately and efficiently.

In the impact vibration test device 100 according to this embodiment, the impact pulse wave 51 is a trapezoidal waveform having an increase portion 51a where the acceleration increases from 0, a maintenance portion 51b where the acceleration is maintained, and a decrease portion 51c where the acceleration decreases to 0, and the adjusted vibration waves 52, 53 are waveforms having acceleration portions 52a, 53a where the acceleration is a positive value, and deceleration portions 52b, 53b where the acceleration is a negative value. With this configuration, the waveform of the entire time history waveform 50 can be adjusted with high precision.

In the impact vibration test device 100 according to this embodiment, the time history waveform 50 is formed so as to be symmetrical in the time axis direction. With this configuration, the waveform of the entire time history waveform 50 can be adjusted with high precision.

The technical scope of the present invention is not limited to the above-described embodiments, and appropriate modifications can be made without departing from the spirit of the present invention.

10 Vibration table 20 Driving unit 30 Control unit 31 Generating unit 32 Driving control unit 33 Memory unit 40 Test body 50, 50A Time history waveform 51, 55 Impact pulse wave 51a Increasing portion 51b Maintaining portion 51c Decreasing portion 52, 53, 56, 57 Adjusted vibration wave 52a, 53a Acceleration portion 52b, 53b Deceleration portion 70 Floor response spectrum 70A Comparison spectrum 71 Target spectrum 100 Impact vibration test device S1, S2 Region T1, T5 Impact period T2, T3, T6, T7 Adjustment period

Claims (5)

A vibration table on which a test specimen is placed;
a driving unit that drives the vibration table to apply acceleration to the test body;
A control unit that controls the driving unit so that an acceleration represented by a time history waveform including a shock pulse wave and an adjusted excitation wave that is arranged before and after the shock pulse wave in time is applied to the test body,
The control unit generates the time history waveform so that a sum of time integral values of the shock pulse wave and the adjusted excitation wave is 0 and a period of the adjusted excitation wave is 10 times or more longer than a period of the shock pulse wave. The shock pulse wave is a trapezoidal waveform having an increasing portion where the acceleration increases from 0, a maintaining portion where the acceleration is maintained, and a decreasing portion where the acceleration decreases to 0,
2. The impact vibration testing device according to claim 1, wherein the adjusted excitation wave is a waveform having an acceleration portion where the acceleration has a positive value and a deceleration portion where the acceleration has a negative value. 3. The impact vibration testing device according to claim 1, wherein the time history waveform is formed so as to be symmetrical in a time axis direction. placing a test specimen on a vibration table;
an impact vibration testing method comprising: generating a time history waveform including an impact pulse wave and an adjusted excitation wave that is respectively arranged before and after the impact pulse wave in time, wherein a sum of time integrals of the impact pulse wave and the adjusted excitation wave is zero and a period of the adjusted excitation wave is 10 times or more longer than a period of the impact pulse wave; and driving the excitation table so that an acceleration indicated by the generated time history waveform is applied to the test specimen. A process for generating a time history waveform including a shock pulse wave and an adjusted excitation wave that is arranged before and after the shock pulse wave in time, the sum of the time integral values of the shock pulse wave and the adjusted excitation wave is 0, and the period of the adjusted excitation wave is 10 times or more longer than the period of the shock pulse wave;
and driving a vibration table on which a test object is placed so that the acceleration represented by the generated time history waveform is applied to the test object.

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