JP2023146320A - Method for creating simulated earthquake motion - Google Patents

Abstract

To provide a method for creating simulated earthquake motion that has been verified against the target spectrum and is within the excitation limits of the excitation device.SOLUTION: The method for creating simulated earthquake motion includes a ninth step (S109) of determining that a candidate simulated earthquake motion that is created in a sixth step (S106) of testing to create a candidate simulated earthquake motion is an excitation limit spectrum (6) of the excitation device or less, and when the created candidate simulated earthquake motion exceeds the excitation limit spectrum (6), correcting the created candidate simulated earthquake motion components in the vibration range that exceed the excitation limit spectrum (6) of the vibration excitation device and recreating the simulated earthquake motion.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for creating simulated earthquake motion.

Seismic testing is a method for investigating the earthquake durability of structures and equipment. In this test, a structure, equipment, or a part thereof is used as a test object, and the test object is placed on a vibrating device such as a shaker or a shaking table, and the seismic load that is expected to act on the structure or equipment is input. . Earthquake resistance, which is the durability required of structures and equipment against earthquakes, and seismic loads acting on structures and equipment are often presented as response spectra. As the earthquake motion used as input in the seismic test, a time history waveform of a simulated earthquake motion that matches the response spectrum (referred to as a target spectrum) is created.

When conducting seismic tests, the acceleration, velocity, and displacement components of the created simulated earthquake motion are below the acceleration, velocity, and displacement limits of the vibration device used in the seismic test, and vibration is possible. Check in advance whether As a result of the confirmation, if the simulated earthquake motion exceeds the excitation limit, countermeasures will be taken such as modifying the simulated earthquake motion or changing the excitation device used in the seismic test so that it can be vibrated.

Against the backdrop of damage to structures and equipment caused by recent earthquakes and the ripple effects of such damage, the seismic performance required of structures and equipment continues to increase. Therefore, in seismic tests, it is often required to evaluate the seismic performance of structures and equipment up to excitation conditions that are close to the limits of the excitation performance of the excitation device, and the conditions for establishing the simulated earthquake motion used as input are will be limited.

Patent Document 1 proposes a vibration testing device that creates a time history waveform of a simulated earthquake motion that is verified against a target spectrum and falls within the excitation limit of an excitation device. This vibration testing apparatus includes a vibrator having a vibrator on which a test object is mounted and a drive mechanism that vibrates the vibrator in at least two different directions in a horizontal plane. The vibration test device includes a control unit that controls driving of the drive mechanism of the vibrator. The vibration testing device includes a calculation unit that creates a waveform of vibration to be applied to the vibrator and provides the created waveform to the control unit. Then, the vibration testing device performs a step of verifying whether the excitation range of the two created waveforms falls within the excitation possible range of the vibration exciter, and then re-tests if the excitation range does not fall within the excitation possible range during the verification. and creating two waveforms. Thereby, the vibration testing device is verified against the target spectrum and then creates a simulated seismic motion that falls within the excitation limits of the vibration excitation device.

JP 2021-96199 Publication

In this way, in the conventional method of creating a simulated earthquake motion, after the step of creating a simulated earthquake motion that has been verified against the target spectrum, it is determined whether the created simulated earthquake motion falls within the excitation limit of the excitation device. do. Therefore, in order to create a simulated earthquake motion that has been verified against the target spectrum and is within the excitation limit of the excitation device, many trials are required to find a place where the two-step process settles. There was a problem with the number of times required.

The present invention was invented to solve the above problems, and its purpose is to efficiently generate simulated earthquake motions that have been verified against the target spectrum and that are within the excitation limit of the excitation device. It is an object of the present invention to provide a method for creating simulated earthquake motions that can be easily created.

A method for creating a simulated earthquake motion according to one aspect of the present invention includes determining that the candidate simulated earthquake motion created in the step of creating a candidate simulated earthquake motion is equal to or less than the excitation limit spectrum of an excitation device, and If the candidate simulated earthquake motion exceeds the excitation limit spectrum, components of the created candidate simulated earthquake motion in a frequency range that exceeds the excitation limit spectrum of the vibration excitation device are corrected to generate the simulated earthquake motion. This includes steps to recreate the .

According to the present invention, in the step of creating a simulated earthquake motion, it is also verified that the vibration limit of the vibration excitation device is not exceeded. This makes it possible to efficiently create a simulated earthquake motion that has been verified against the target spectrum and that falls within the excitation limit of the vibration excitation device.

FIG. 1 is a block diagram showing a system configuration of a simulated seismic motion creation device according to an embodiment. FIG. 2 is a flowchart showing a method for creating a simulated earthquake motion according to the embodiment. FIG. 3A is a diagram showing part of the input data in the method for creating a simulated earthquake motion according to the embodiment, and shows an envelope function. FIG. 3B is a diagram showing part of the input data in the method for creating a simulated earthquake motion according to the embodiment, and shows a target spectrum and an excitation limit spectrum. FIG. 4A is a diagram showing a part of the output results in the method for creating a simulated earthquake motion according to the embodiment, and shows a target spectrum, an excitation limit spectrum, and a response spectrum of the simulated earthquake motion. FIG. 4B is a diagram showing a part of the output result in the method for creating a simulated earthquake motion according to the embodiment, and shows a time history waveform. FIG. 5 is a diagram showing an example of an excitation limit spectrum setting screen displayed by the display unit according to the embodiment. FIG. 6 is a diagram illustrating an example of a display screen of simulated earthquake motion creation results displayed by the display unit according to the embodiment. FIG. 7 is a flowchart showing a method for creating a simulated earthquake motion using a conventional method.

Embodiments of the present invention will be described below with reference to text and drawings. The various specific configurations shown in the present invention are not limited to the embodiments discussed here, and can be appropriately combined and improved without changing the gist. Further, illustrations of elements not directly related to the present invention are omitted.

<<How to create simulated earthquake motion>>
A method for creating a simulated earthquake motion according to this embodiment will be explained using FIGS. 1 to 4. FIG. 1 is a block diagram showing the system configuration of an apparatus for creating a simulated earthquake motion using the method for creating a simulated earthquake motion of this embodiment. FIG. 2 is a flowchart showing the procedure for creating a simulated earthquake motion when the method for creating a simulated earthquake motion of this embodiment is adopted. FIG. 3A is a diagram showing some input data in the method for creating a simulated earthquake motion of this embodiment, and shows an envelope function. FIG. 3B is a diagram showing some input data in the method for creating a simulated earthquake motion of this embodiment, and shows a target spectrum and an excitation limit spectrum. FIG. 4A is a diagram showing some output data in the method for creating a simulated earthquake motion of this embodiment, and shows the target spectrum, the excitation limit spectrum, and the response spectrum of the simulated earthquake motion. FIG. 4B is a diagram showing some output data in the method for creating a simulated earthquake motion of this embodiment, and shows a time history waveform.

<<Simulated seismic motion creation device 1>>
First, the system configuration of an apparatus for creating a simulated earthquake motion will be described using FIG. The simulated seismic motion creation device 1 shown in FIG. A user of the simulated earthquake motion creation device 1 inputs input data Da1, outputs output data Da2, and operates the simulated earthquake motion creation device 1 via the input/output display section 2. Input data Da1 is stored in the storage unit 101. When creating a simulated earthquake motion is executed, necessary data is sent from the storage unit 101 to the calculation unit 102. Then, the calculation unit 102 performs calculations for creating a simulated earthquake motion according to a procedure for creating a simulated earthquake motion, which will be described later. The calculation unit 102 is composed of a microcomputer and its peripheral devices. The result of the calculation in the calculation unit 102 is stored in the storage unit 101. The user of the simulated seismic motion creation device 1 can check the output data Da2 on the input/output display section 2.

The input data Da1 is roughly divided into conditions for creating seismic motion and conditions used for verification. The conditions for creating an earthquake motion are the initial random number of the phase spectrum, the envelope function 4 (see Figure 3A), the target spectrum 5 (see Figure 3B), the allowable number of corrections for the Fourier amplitude, and the conditions used for verification are the candidate simulated earthquake motion for the target spectrum. The tolerance value of the response spectrum error and the excitation limit spectrum 6 (see FIG. 3B) are set.

Here, the simulated earthquake motion before the verification at the stage of creating the simulated earthquake motion is referred to as a candidate simulated earthquake motion. Envelope function 4 is set to specify the temporal characteristics of the simulated earthquake motion to be created, and is a function of time and normalized amplitude shown in FIG. 3A. In addition, the target spectrum 5 and the excitation limit spectrum 6 are defined as the relationship between the amplitude component of the seismic motion and the frequency component as shown in FIG. 3B. In FIG. 3B, the frequency component is the frequency, and the amplitude component of the seismic motion is the It's speeding up. The target spectrum 5 is a response spectrum that specifies the seismic performance required of the structure or equipment and the seismic load acting on the structure or equipment. The excitation limit spectrum 6 is a response spectrum indicating the excitation possible range of the excitation device.

In addition, as output data Da2, the response spectrum 7 of the created simulated earthquake motion (see FIG. 4A), the time history waveform 8 (see FIG. 4B), the maximum acceleration, the maximum velocity, the maximum displacement, and the target spectrum 5 of the response spectrum 7 of the simulated earthquake motion. Alternatively, a spectrum ratio obtained as a ratio to the excitation limit spectrum 6 can be mentioned. As an example of the output data Da2, FIG. 4A shows the response spectrum 7 (solid line) of the created simulated earthquake motion together with the target spectrum 5 (dotted line) and the excitation limit spectrum 6 (dashed line). FIG. 4B shows an acceleration time history waveform 8 of the simulated earthquake motion.

<<Procedure for creating simulated earthquake motion>>
Next, a procedure for creating a simulated earthquake motion according to this embodiment will be explained using FIG. 2. Note that the method for creating the simulated earthquake motion of this embodiment partially uses a method called the spectral adaptation method (for example, see "New Introduction to Spectral Analysis of Earthquake Motion" by Yoshihiko Osaki, Kashima Publishing). A description of the specific calculation contents will be omitted. In addition, among the spectrum adaptation methods, a method for creating a simulated earthquake motion in which the phase characteristics of the simulated earthquake motion are set based on uniform random numbers is particularly targeted. In the spectrum matching method, complex Fourier coefficients consisting of a Fourier amplitude spectrum and a Fourier phase spectrum are set, and an acceleration time history waveform is obtained by inverse Fourier transform of the complex Fourier coefficients. By multiplying the obtained time history waveform by an envelope function, a candidate simulated earthquake motion having temporal characteristics is created, and a response spectrum 7 of the created candidate simulated earthquake motion is calculated. The degree of compatibility of the response spectrum 7 of the obtained candidate simulated earthquake motion with the target response spectrum is tested. If the test conditions are satisfied, the candidate simulated earthquake motion is adopted as a simulated earthquake motion, and the process of creating a simulated earthquake motion is completed. On the other hand, if the test conditions are not satisfied, the Fourier amplitude spectrum is corrected based on the ratio between the response spectrum 7 of the candidate simulated earthquake motion and the target response spectrum, and the creation and verification of the candidate simulated earthquake motion is repeated from the inverse Fourier transform procedure.

<<Process flow for creating simulated earthquake motion>>
In creating the simulated earthquake motion of this embodiment, the calculation unit 102 first uses the input data Da1 shown in FIG. Load. As conditions for creating a simulated earthquake motion, an initial random number for the phase spectrum and an allowable number of corrections for the Fourier amplitude spectrum are set.

Next, in the Fourier amplitude initial condition setting in the second step S102, the calculation unit 102 creates a Fourier amplitude spectrum of the initial condition. There are various methods for providing the initial Fourier amplitude spectrum, but one example is a method that uses a normalized target spectrum 5 set using the input data Da1 shown in FIG. 2.

Subsequently, in the sine wave synthesis in the third step S103, the calculation unit 102 uses the Fourier amplitude spectrum obtained in the second step S102 and the initial random number of the phase spectrum set with the input data Da1 shown in FIG. The Fourier phase spectrum obtained by creating uniform random numbers and the complex Fourier coefficients are calculated. An acceleration time history waveform is obtained by performing inverse Fourier transform on the calculated complex Fourier coefficients.

Subsequently, in calculating the time function in the fourth step S104, the calculation unit 102 multiplies the acceleration time history waveform obtained in the third step S103 by the envelope function 4 set using the input data Da1 shown in FIG. By doing this, the acceleration time history waveform of the candidate simulated earthquake motion is obtained.

Subsequently, in the response spectrum calculation in the fifth step S105, the calculation unit 102 performs a response spectrum analysis on the acceleration time history waveform of the candidate simulated earthquake motion obtained in the fourth step S104, and calculates the response of the candidate simulated earthquake motion. Calculate spectrum 7.

Next, in determining whether the response spectrum 7 of the candidate simulated earthquake motion satisfies the test condition for the target spectrum 5, the excitation limit spectrum 6 or less, in the sixth step S106, the calculation unit 102 determines that the response spectrum 7 of the candidate simulated earthquake motion It is determined whether the tolerance value of the response spectrum error is satisfied and the excitation limit spectrum is 6 or less. In this determination, a spectral excess ratio is calculated as the amplitude ratio of the response spectrum 7 of the candidate simulated earthquake motion to the excitation limit spectrum 6.

If the response spectrum 7 of the candidate simulated earthquake motion satisfies the determination conditions in the sixth step S106, the candidate simulated earthquake motion is adopted as the simulated earthquake motion, and the process proceeds to the seventh step S107 to write out the output data Da2 shown in FIG. The seismic motion creation process ends.

On the other hand, if the response spectrum 7 of the candidate simulated earthquake motion does not satisfy the determination condition in the sixth step S106, the calculation unit 102 moves to the eighth step S108, and the calculation unit 102 moves to the eighth step S108, and the calculation unit 102 moves to the eighth step S108, and the number of trials i reaches the allowable number N of Fourier amplitude corrections. Determine whether or not. If the number of trials i has not reached the allowable number of Fourier amplitude corrections N, the calculation unit 102 corrects the Fourier amplitude as a ninth step S109.

Thereafter, in a tenth step S110, the calculation unit 102 increases the number of trials i by 1 and returns to the sine wave synthesis in the third step S103 using the corrected Fourier amplitude to create a candidate simulated earthquake motion.

When the judgment conditions for the target spectrum 5 are not satisfied, the Fourier amplitude spectrum is corrected by multiplying the Fourier amplitude spectrum used in the step by the ratio of the target spectrum 5 to the response spectrum 7 of the candidate simulated earthquake motion. Correct the spectrum. In addition, if the judgment conditions for the excitation limit spectrum 6 are not satisfied, in the frequency range that does not exceed the excitation limit spectrum 6 of the response spectrum 7 of the created candidate simulated earthquake motion, in the frequency range that exceeds 1. The Fourier amplitude spectrum is corrected by multiplying the ratio of the excitation limit spectrum 6 to the response spectrum 7 of the candidate simulated earthquake motion. In other words, if the creation result of the simulated earthquake motion does not satisfy the verification conditions, the Fourier amplitude spectrum is multiplied by the tolerance value of the response spectrum error and the reciprocal of the spectral excess ratio in the frequency range where the spectral excess ratio exceeds 1. By combining these, the conditions for creating candidate simulated earthquake motions are corrected.

On the other hand, when the number of trials i reaches the permissible number of Fourier amplitude corrections N in the eighth step S108, the calculating unit 102 calculates the phase spectrum specified by the input data Da1 in the eleventh step S111. It is determined that the study of creating a simulated earthquake motion using initial random numbers has diverged. In that case, in updating the initial random number in the twelfth step S112, the calculation unit 102 changes the initial random number of the phase spectrum set with the input data Da1 shown in FIG. 1 to a different value. After that, a Fourier phase spectrum is obtained based on the updated initial random number, and the sine wave synthesis in the third step S103 is performed again.

<<Example of system input screen and output screen>>
Next, FIGS. 5 and 6 show examples of an input screen and an output screen of a system to which the method for creating a simulated seismic motion of the present invention is applied, respectively.

FIG. 5 shows the conditions for creating a simulated earthquake motion and the settings of the excitation limit spectrum 6 shown in the first step S101 in FIG. This is an example of a case where the vibration limit spectrum is set, and is a diagram showing an excitation limit spectrum setting screen 9. The excitation limit spectrum setting screen 9 includes an excitation limit spectrum input method selection button 10, a response spectrum frequency axis display condition setting button 11, a response spectrum amplitude display condition setting button 12, an excitation limit spectrum input table 13, and an excitation limit spectrum. 6 and a target spectrum 5. First, the input method for the excitation limit spectrum 6 is selected using the excitation limit spectrum input method selection button 10. When "table" is selected with the excitation limit spectrum input method selection button 10, the frequency and amplitude data of the excitation limit spectrum 6 are input into the excitation limit spectrum input table 13, respectively. When "Refer to DB" is selected with the vibration limit spectrum input method selection button 10, the vibration limit spectrum data of the vibration device used in the vibration test prepared in advance is read. That is, the data of the excitation device and the excitation limit conditions of the excitation device in which the excitation limit spectrum 6 is set in advance are selected from the database. With the response spectrum frequency axis display condition setting button 11, a frequency axis that is referred to in the illustration of the excitation limit spectrum input table 13, the excitation limit spectrum 6, and the target spectrum 5 is set. Similarly, with the response spectrum amplitude display condition setting button 12, the amplitude of the response spectrum 7 of the simulated earthquake motion is set. After the data of the excitation limit spectrum 6 is input, by pressing the display execution button, the excitation limit spectrum 6 is displayed in the illustration of the excitation limit spectrum 6 and the target spectrum 5 together with the target spectrum 5 which is set separately. It will be done.

Here, as a condition for creating a simulated earthquake motion, the response spectrum (referred to as the allowable target spectrum) obtained by adding the tolerance value of response spectrum error to the target spectrum 5 set in the first step S101 in FIG. Must be set as a small amplitude. However, the target spectrum 5 is determined based on the seismic performance required of the structure or equipment and the seismic load acting on the structure or equipment. On the other hand, the excitation limit spectrum 6 is determined as the excitation possible range of the excitation device, and the permissible target spectrum is not necessarily smaller than the excitation limit spectrum 6. If the allowable target spectrum exceeds the excitation limit spectrum 6, it is necessary to correct the allowable target spectrum so that it becomes equal to or less than the excitation limit spectrum 6. In other words, the target/excitation limit spectrum ratio is calculated as the amplitude of the target spectrum 5 with respect to the amplitude of the excitation limit spectrum 6, and the product of the target/excitation limit spectrum ratio and the tolerance value of the response spectrum error is 1 or more. If it exceeds the excitation limit spectrum, it is necessary to correct the allowable target spectrum so that it becomes equal to or less than the excitation limit spectrum 6.

The correction methods that can be presented on the display screen include a correction method that re-registers the input data of the target spectrum 5, a correction method that removes frequency components that exceed the excitation limit spectrum 6 in the target spectrum 5, and a correction method that removes the frequency components that exceed the excitation limit spectrum 6. A method of correcting based on the spectrum 6 is mentioned.

In the correction method of removing frequency components exceeding the excitation limit spectrum 6 in the target spectrum 5, the amplitude of the frequency range exceeding the excitation limit spectrum 6 of the target spectrum 5 is set to 0 using the following equation 1. Make corrections. In other words, when a modification method for removing the amplitude of the target spectrum 5 is designated, a range in which the amplitude is to be removed is designated, and a target spectrum 5 in which the amplitude components in the designated range are removed is calculated.

Here, k is the frequency, S _v ^T is the target spectrum, Ra is the allowable value of response spectrum error, and S _v ^L is the excitation limit spectrum.

In addition, in the method of modifying based on the excitation limit spectrum 6, the target spectrum 5 is modified using Equation 2 below so that the allowable target spectrum matches the excitation limit spectrum 6. In other words, when the method of correction is specified by the excitation limit spectrum 6, the tolerance value of the response spectrum error is subtracted from the excitation limit spectrum 6 for components in the frequency range exceeding the excitation limit of the excitation device. The amplitude of the target spectrum 5 is corrected as the value.

Here, k is the frequency, S _v ^T is the target spectrum, Ra is the allowable value of response spectrum error, and S _v ^L is the excitation limit spectrum.

＜＜Creation results of simulated earthquake motion＞＞
FIG. 6 is an example of the method for creating a simulated earthquake motion according to the present embodiment in which the result of creating a simulated earthquake motion is displayed on the input/output display section 2 of FIG. The simulated earthquake motion creation result display screen 14 is composed of a response spectrum frequency axis display condition setting button 11, a response spectrum amplitude display condition setting button 12, a summary 15 of the simulated earthquake motion creation result, an illustration execution button, and an illustration of the response spectrum 7 of the simulated earthquake motion. has been done. The response spectrum frequency axis display condition setting button 11 sets the frequency axis. The response spectrum amplitude display condition setting button 12 is used to set display conditions for displaying the response spectrum. By pressing the illustration execution button after setting, the response spectrum 7 of the simulated earthquake motion is displayed together with the target spectrum 5 and the excitation limit spectrum 6 in the response spectrum illustration. In addition, the summary 15 of the simulation earthquake motion creation results includes the spectrum ratio of the response spectrum 7 of the simulated earthquake motion to the target spectrum 5, the spectrum ratio of the response spectrum 7 of the simulated earthquake motion to the excitation limit spectrum 6, maximum acceleration, maximum velocity, maximum displacement. The main information of the simulation earthquake motion creation results is displayed.

<<How to create simulated earthquake motion using conventional methods>>
For comparison with this embodiment, a method for creating a simulated earthquake motion that has been verified against the target spectrum 5 using the conventional method and that falls within the excitation limit of the excitation device will be explained using FIG. 7. . FIG. 7 is a flowchart showing a method for creating a simulated earthquake motion using a conventional method. In particular, in order to focus on the difference from the method for creating a simulated earthquake motion according to the present embodiment, reference will be made to the steps in the flowchart of the method for creating a simulated earthquake motion according to the present embodiment shown in FIG.

In setting the conditions for creating the simulated earthquake motion shown in step S201 in FIG. Set the tolerance value for response spectrum error of simulated earthquake motion.

Subsequently, in the Fourier amplitude initial condition setting shown in step S202 of FIG. 7, the calculation unit 102 performs the same process as the second step S102 shown in FIG. In the sine wave synthesis shown in step S203 of FIG. 7, the calculation unit 102 performs the same process as the third step S103 shown in FIG. In the time function calculation shown in step S204 of FIG. 7, the calculation unit 102 performs the same process as the fourth step S104 shown in FIG. In calculating the response spectrum 7 of the simulated earthquake motion shown in step S205 of FIG. 7, the calculation unit 102 performs the same process as the fifth step S105 shown in FIG.

Subsequently, in determining whether the test conditions shown in step S206 of FIG. judge. When the response spectrum 7 of the candidate simulated earthquake motion satisfies the determination condition in step S206, the calculation unit 102 employs the candidate simulated earthquake motion as the simulated earthquake motion in the simulated earthquake motion generation shown in step S207 of FIG.

Subsequently, in setting the vibration enable/disable conditions shown in step S208 in FIG. 7, the calculation unit 102 sets the vibration limit spectrum 6. Then, when determining that the response spectrum 7 of the simulated earthquake motion shown in step S209 of FIG. It is determined whether the vibration limit spectrum is 6 or less. If the response spectrum 7 of the simulated earthquake motion satisfies the determination condition in step S208, the calculation unit 102 determines that the response spectrum 7 of the simulated earthquake motion obtained in step S207 has been verified against the target spectrum 5, and The simulated earthquake motion is adopted as a simulated earthquake motion that falls within the excitation limit of the vibration excitation device, and the simulated earthquake motion creation process is completed.

On the other hand, if the response spectrum 7 of the candidate simulated earthquake motion does not satisfy the determination condition in step S206 of FIG. It is determined whether the number of trials i has reached the number N of permissible Fourier amplitude corrections. If the number of trials i in step S210 does not reach the allowable number N of Fourier amplitude corrections, the calculation unit 102 corrects the Fourier amplitude as step S211, and as step S212, performs correction of the Fourier amplitude in the same manner as step S111 shown in FIG. The number of trials i is increased by one, and the process returns to the sine wave synthesis in step S203 using the corrected Fourier amplitude to create a candidate simulated earthquake motion.

Further, when the number of trials i reaches the allowable number of Fourier amplitude corrections N in step S210 of FIG. 7, the calculation unit 102 determines that the study of creating a simulated earthquake motion in step S213 has diverged. In that case, in reviewing the creation conditions shown in step S214, the calculation unit 102 changes some of the creation conditions for the simulated earthquake motion set in step S206, and performs the calculation again from the Fourier amplitude initial condition settings in step S202. Start over.

Furthermore, even if the response spectrum of the candidate simulated earthquake motion does not satisfy the determination conditions in step S209 in FIG. Redo the calculation.

From the above, when creating a simulated earthquake motion that has been verified against the target spectrum 5 using the conventional method and is within the excitation limit of the vibration excitation device, the time history waveform 8 that has been verified against the target spectrum 5 is Created. Thereafter, it is determined whether the created time history waveform 8 falls within the excitation limit range of the vibration excitation device. For this reason, even if the test for the target spectrum 5 is satisfied, a time history waveform 8 that exceeds the excitation limit range of the excitation device may be created. Therefore, the number of trials required to create a simulated earthquake motion increases.

<<Effects of this embodiment>>
On the other hand, in the method for creating a simulated earthquake motion of this embodiment, the degree of conformity to the target spectrum 5 and being below the excitation limit of the vibration device are included in the determination conditions in the step of creating a simulated earthquake motion. This makes it possible to efficiently create a simulated earthquake motion that has been verified against the target spectrum 5 and that falls within the excitation limit of the vibration excitation device.

Furthermore, in the method for creating a simulated earthquake motion of this embodiment, if the number of trials reaches the allowable number of Fourier amplitude corrections without satisfying the test conditions, it is specified that the initial random number is updated as a condition for changing the creation conditions. and repeat the calculation. Therefore, there is no need to review the production conditions using the conventional method. Therefore, the work time required for checking the simulation earthquake motion creation results, reconsidering conditions, and setting work can be reduced.

Furthermore, in the method for creating a simulated seismic motion of this embodiment, the target spectrum 5 and the added The magnitude relationship of the vibration limit spectrum 6 is checked at the initial setting stage and corrected to appropriate conditions as necessary. Therefore, compared to the conventional method of creating a simulated earthquake motion that does not take into account the excitation limit spectrum 6 when creating a simulated earthquake motion, the simulation is verified against the target spectrum 5 and falls within the excitation limit range of the vibration excitation device. It becomes possible to efficiently create seismic motion.

<<Effect of differences>>
(A)
The method for creating a simulated earthquake motion is to determine that the candidate simulated earthquake motion created in the test in the sixth step S106 of creating a candidate simulated earthquake motion is equal to or less than the excitation limit spectrum 6 of the excitation device. Then, the method for creating the simulated earthquake motion is such that if the response spectrum 7 of the candidate simulated earthquake motion does not satisfy the determination condition in the sixth step S106, the response spectrum 7 of the candidate simulated earthquake motion exceeds the excitation limit spectrum 6 of the vibration excitation device among the created candidate simulated earthquake motions. The method includes a step of recreating the simulated earthquake motion by correcting components in the frequency range.

According to this configuration, in the sixth step S106 of creating a simulated earthquake motion, the target spectrum 5 is verified by also verifying that the created simulated earthquake motion does not exceed the excitation limit spectrum 6 of the vibration excitation device. In addition, it becomes possible to efficiently create a simulated earthquake motion that falls within the excitation limit of the vibration excitation device.

(B)
The method for creating a simulated earthquake motion is to set the tolerance value of the response spectrum error and the excitation limit spectrum 6, which are obtained as the amplitude ratio of the response spectrum 7 of the candidate simulated earthquake motion to the amplitude of the target spectrum 5, as the verification conditions for the candidate simulated earthquake motion to be created. do. The method for creating the simulated earthquake motion is to calculate the spectral excess ratio, which is determined as the amplitude ratio of the response spectrum 7 of the candidate simulated earthquake motion to the excitation limit spectrum 6. The method for creating a simulated earthquake motion is that if the creation result of the candidate simulated earthquake motion does not satisfy the verification conditions, the tolerance value of the response spectrum error, the reciprocal of the spectral excess ratio in the frequency range where the spectral excess ratio exceeds 1, By multiplying the Fourier amplitude spectrum by the Fourier amplitude spectrum, the conditions for creating the candidate simulated earthquake motion are corrected, and the candidate simulated earthquake motion is created and verified again. The method for creating a simulated earthquake motion is to acquire the candidate simulated earthquake motion as a simulated earthquake motion when the result of creating the candidate simulated earthquake motion satisfies the verification conditions.

According to this configuration, when the creation result of the simulated earthquake motion does not satisfy the verification conditions, the creation conditions of the candidate simulated earthquake motion are automatically corrected, and the simulation earthquake motion that falls within the excitation limit of the vibration excitation device is efficiently created. becomes possible.

(C)
The method for creating a simulated earthquake motion is to create a candidate simulated earthquake motion by setting an initial random number for a phase spectrum and an allowable number of corrections for a Fourier amplitude spectrum as conditions for creating a simulated earthquake motion. The method for creating a simulated earthquake motion is to update the initial random number of the phase spectrum and create a candidate simulated earthquake motion again if the result of creating the candidate simulated earthquake motion does not satisfy the test conditions by the number of times the Fourier amplitude spectrum is allowed to be corrected.

According to this configuration, if the creation result of the candidate simulated earthquake motion does not satisfy the test conditions within the allowable number of corrections of the Fourier amplitude spectrum, the initial random number of the phase spectrum is updated and the candidate simulated earthquake motion is created again. This saves the user the trouble of updating the initial random numbers, and it becomes possible to efficiently create a simulated seismic motion that falls within the excitation limit of the excitation device.

(D)
In the method for creating a simulated earthquake motion, in the sixth step S106 of setting the test conditions for the candidate simulated earthquake motion, a target/excitation limit spectrum ratio is calculated as the amplitude of the target spectrum 5 with respect to the amplitude of the excitation limit spectrum 6. The method for creating a simulated earthquake motion is that if the product of the target/excitation limit spectrum ratio and the response spectrum error tolerance is 1 or more and exceeds the excitation limit spectrum of the excitation device, the target spectrum 5. A modification method for re-registering input data, a modification method for removing the amplitude of the target spectrum 5, and a modification method using the excitation limit spectrum 6 will be presented.

According to this configuration, when the product of the target/excitation limit spectrum ratio and the tolerance value of response spectrum error becomes 1 or more and exceeds the excitation limit spectrum of the excitation device, the excitation of the excitation device It is automatically determined that it is not possible to create a simulated earthquake motion that falls within the limits, and it is possible to prompt the user for instructions.

(E)
The method for creating a simulated earthquake motion is that when a correction method that removes the amplitude of the target spectrum 5 is specified, the range in which the amplitude is removed is specified, and the target spectrum 5 is calculated by removing the amplitude components in the specified range. conduct. The method for creating a simulated earthquake motion is to create a response spectrum from the excitation limit spectrum 6 for components in a frequency range that exceeds the excitation limit spectrum 6 of the vibration excitation device when a method of modification using the excitation limit spectrum 6 is specified. The amplitude of the target spectrum 5 is corrected by subtracting the allowable error value.

According to this configuration, it is possible to efficiently create a simulated seismic motion that falls within the excitation limit of the vibration excitation device in accordance with the correction method according to the user's instructions.

(F)
The method for creating the simulated earthquake motion is to select from the database the data of the vibration device in which the vibration limit spectrum 6 has been set in advance and the vibration limit conditions of the vibration device.

According to this configuration, the user can appropriately select the data of the vibration device and the vibration limit conditions of the vibration device from the database.

(G)
The method for creating a simulated earthquake motion includes a first step S101 of setting conditions for creating a simulated earthquake motion and an excitation limit spectrum 6. The method for creating a simulated earthquake motion includes a second step S102 of creating a Fourier amplitude spectrum of initial conditions and setting the Fourier amplitude initial conditions. The method for creating a simulated earthquake motion is to calculate the complex Fourier coefficients, which are composed of the Fourier amplitude spectrum of the initial conditions and the Fourier phase spectrum obtained by creating uniform random numbers using the initial random numbers of the phase spectrum. A third step S103 is included in which a sine wave is synthesized to obtain an acceleration time history waveform by subjecting the complex Fourier coefficients to an inverse Fourier transform. The method for creating a simulated earthquake motion includes a fourth step S104 of calculating a time function to obtain an acceleration time history waveform of a candidate simulated earthquake motion by multiplying the acceleration time history waveform by an envelope function 4. The method for creating a simulated earthquake motion includes a fifth step S105 in which response spectrum analysis is performed on the acceleration time history waveform of the candidate simulated earthquake motion, and response spectrum calculation is performed to calculate the response spectrum 7 of the candidate simulated earthquake motion. The method for creating a simulated earthquake motion has the goal of determining whether the response spectrum 7 of the candidate simulated earthquake motion satisfies the tolerance value of the response spectrum error of the candidate simulated earthquake motion with respect to the target spectrum 5, and is less than or equal to the excitation limit spectrum 6. A sixth step S106 is included in which it is determined whether the verification conditions for spectrum 5 and the excitation limit spectrum 6 or less are satisfied. The method for creating a simulated earthquake motion includes a seventh step S107 in which, when the response spectrum 7 of the candidate simulated earthquake motion satisfies the determination condition of the sixth step S106, the candidate simulated earthquake motion is adopted as the simulated earthquake motion and output data Da2 is written. The method for creating a simulated earthquake motion includes the eighth step of determining whether the number of trials i has reached the allowable number N of Fourier amplitude corrections when the response spectrum 7 of the candidate simulated earthquake motion does not satisfy the determination condition of the sixth step S106. Includes S108. The method for creating a simulated earthquake motion includes a ninth step S109 in which the Fourier amplitude is corrected when the number of trials i does not reach the allowable number of Fourier amplitude corrections N. The method for creating a simulated earthquake motion includes a tenth step S110 in which, after correcting the Fourier amplitude, the number of trials i is increased by 1, and the process returns to the third step S103 in which a candidate simulated earthquake motion is created using the corrected Fourier amplitude. . The method for creating a simulated earthquake motion includes an 11th step in which it is determined that the study of creating a simulated earthquake motion using the initial random number of the phase spectrum has diverged when the number of trials i reaches the allowable number N of Fourier amplitude corrections. Includes S110. The method for creating a simulated earthquake motion includes, following the eleventh step S110, changing the initial random number of the phase spectrum to a different value to update the initial random number, and then calculating the acceleration time history waveform based on the updated initial random number. 3 includes a twelfth step S112 returning to step S103.

According to this configuration, in the sixth step S106 of creating a simulated earthquake motion, by also verifying that the excitation limit spectrum 6 of the vibration excitation device is not exceeded, the target spectrum 5 is verified, and the vibration excitation device It becomes possible to efficiently create a simulated earthquake motion that falls within the excitation limit of .

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. do not have.

1... Simulated earthquake motion creation device, 2... Input display section, 4... Envelope function, 5... Target spectrum, 6... Excitation limit spectrum, 7... Response spectrum of simulated earthquake motion, 8... Time history waveform, 9... Excitation limit spectrum Setting screen, 10...Excitation limit spectrum input method selection button, 11...Response spectrum frequency axis display condition setting button, 12...Response spectrum amplitude display condition setting button, 13...Excitation limit spectrum input table, 14...Simulated seismic motion creation result Display screen, 15...Summary of simulated earthquake motion creation results, 101...Storage unit, 102...Calculation unit.

Claims (7)

A method for creating a simulated earthquake motion, the method comprising:
determining that the candidate simulated earthquake motion created in the verification of the step of creating a candidate simulated earthquake motion is below the excitation limit spectrum of the excitation device;
If the created candidate simulated earthquake motion exceeds the excitation limit spectrum, correct components of the created candidate simulated earthquake motion in a frequency range that exceeds the excitation limit spectrum of the excitation device. A method for creating a simulated earthquake motion, including the step of re-creating the simulated earthquake motion. The method for creating a simulated earthquake motion according to claim 1,
As the test conditions for the candidate simulated earthquake motion to be created,
setting the excitation limit spectrum and a tolerance value for a response spectrum error obtained as an amplitude ratio of the response spectrum of the candidate simulated earthquake motion to the amplitude of the target spectrum;
Calculating a spectral excess ratio obtained as an amplitude ratio of the response spectrum of the candidate simulated earthquake motion to the excitation limit spectrum,
If the creation result of the candidate simulated earthquake motion does not satisfy the test conditions, the tolerance value of the response spectrum error and the reciprocal of the spectral excess ratio in the frequency range in which the spectral excess ratio exceeds 1 are calculated by Fourier analysis. correcting the conditions for creating the candidate simulated earthquake motion by multiplying it by the amplitude spectrum, and creating the candidate simulated earthquake motion and performing the verification again;
A method for creating a simulated earthquake motion, wherein when the creation result of the candidate simulated earthquake motion satisfies the test conditions, the candidate simulated earthquake motion is acquired as the simulated earthquake motion. The method for creating a simulated earthquake motion according to claim 2,
Creating the candidate simulated earthquake motion by setting an initial random number of the phase spectrum and an allowable number of corrections of the Fourier amplitude spectrum as conditions for creating the simulated earthquake motion,
If the creation result of the candidate simulated earthquake motion does not satisfy the test condition by the number of times of permissible correction of the Fourier amplitude spectrum, the initial random number of the phase spectrum is updated and the candidate simulated earthquake motion is created again. How to make. The method for creating a simulated earthquake motion according to claim 2,
In the step of setting the test conditions for the candidate simulated earthquake motion,
calculating a target/excitation limit spectrum ratio as the amplitude of the target spectrum to the amplitude of the excitation limit spectrum;
If the product of the target/excitation limit spectrum ratio and the response spectrum error tolerance is 1 or more and exceeds the excitation limit spectrum of the excitation device,
A correction method for re-registering the input data of the target spectrum;
a modification method for removing the amplitude of the target spectrum;
A method of correcting using the excitation limit spectrum;
Presents a method for creating simulated earthquake motion. The method for creating a simulated earthquake motion according to claim 4,
If a modification method for removing the amplitude of the target spectrum is specified,
specifying a range in which the amplitude is to be removed, and calculating the target spectrum from which the amplitude components in the specified range have been removed;
If the method of correction is specified by the excitation limit spectrum,
A method for creating a simulated earthquake motion, in which the amplitude of the target spectrum is corrected as a value obtained by subtracting the tolerance value of the response spectrum error from the excitation limit spectrum for components in a frequency range exceeding the excitation limit spectrum of the vibration excitation device. . The method for creating a simulated earthquake motion according to claim 2,
A method for creating a simulated earthquake motion, comprising selecting data of the vibration excitation device in which the vibration limit spectrum is set in advance and vibration limit conditions of the vibration vibration device from a database. A method for creating a simulated earthquake motion, the method comprising:
A first step of setting conditions for creating the simulated earthquake motion and an excitation limit spectrum;
a second step of creating a Fourier amplitude spectrum of initial conditions and setting the Fourier amplitude initial conditions;
A complex Fourier coefficient is calculated, which is composed of the Fourier amplitude spectrum under the initial conditions and the Fourier phase spectrum obtained by creating a uniform random number using the initial random number of the phase spectrum, and the calculated complex Fourier coefficient is A third step of obtaining an acceleration time history waveform by inverse transformation;
a fourth step of calculating a time function to obtain an acceleration time history waveform of a candidate simulated earthquake motion by multiplying the acceleration time history waveform and an envelope function;
a fifth step of calculating a response spectrum of the candidate simulated earthquake motion by performing a response spectrum analysis on the acceleration time history waveform of the candidate simulated earthquake motion;
a sixth step of determining whether the response spectrum of the candidate simulated earthquake motion satisfies the tolerance value of the response spectrum error of the candidate simulated earthquake motion with respect to the target spectrum and is below the excitation limit spectrum;
a seventh step of employing the candidate simulated earthquake motion as a simulated earthquake motion and writing output data when the response spectrum of the candidate simulated earthquake motion satisfies the determination condition of the sixth step;
If the response spectrum of the candidate simulated earthquake motion does not satisfy the determination condition of the sixth step, an eighth step of determining whether the number of trials i has reached the number of permissible corrections N of Fourier amplitude;
a ninth step of correcting the Fourier amplitude when the number of trials i does not reach the allowable number of corrections N of the Fourier amplitude;
After correcting the Fourier amplitude, a tenth step of increasing the number of trials i by 1 and returning to the third step using the corrected Fourier amplitude;
an eleventh step in which it is determined that the study of creating a simulated earthquake motion using the initial random number of the phase spectrum has diverged when the number of trials i reaches the number N of permissible corrections of Fourier amplitude;
Continuing to the eleventh step, the initial random number of the phase spectrum is changed to a different value to update the initial random number, and then the third step of determining the acceleration time history waveform based on the updated initial random number. The 12th step of going back,
Including how to create simulated earthquake motion.

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