Structural analysis system and structural analysis method

Abstract

Modal analysis is performed by synchronizing multiple vibration signals detected by multiple wireless sensors. [Solution] One aspect of the present disclosure is a structural analysis system comprising: a plurality of vibration sensors installed at different locations on a structure to detect vibrations of the structure; a synchronization unit that synchronizes a plurality of vibration signals indicating vibrations detected by the plurality of vibration sensors; and an analysis unit that performs modal analysis of the structure based on each of the plurality of vibration signals synchronized by the synchronization unit. The synchronization unit acquires a plurality of vibration signals from the plurality of vibration sensors and synchronizes the plurality of vibration signals based on at least one of the installation locations of the plurality of vibration sensors, the distance from the plurality of vibration sensors to the acquisition unit, and the transmission speed of the vibration signals.

Description

Technical Field

[0001] The present invention relates to a structure analysis system and a structure analysis method.

Background Art

[0002] Conventionally, techniques for analyzing deformations of structures such as bridges have been known. In order to monitor the deformation of a structure, there is a technique for monitoring the deformation of a single measurement point of the structure, or there is a case where monitoring is performed linearly or planarly by monitoring a plurality of measurement points of the structure. Further, it has also been conventionally known to monitor the linear deformation of a structure using an optical fiber or the like.

[0003] As the above-described techniques, for example, Patent Documents 1 and 2 are known. The soundness evaluation system described in Patent Document 1 measures the response displacement of the top end of a pier when a train passes, calculates the limit value of sound displacement based on the structural specifications of the pier, and compares the measured value of the response displacement with the limit value to determine the soundness. The dynamic displacement estimation system described in Patent Document 2 installs a dynamic displacement detection unit for each of a plurality of measurement points arranged at predetermined intervals in the extending direction of a track, converts the vibration of the track into electrical energy by a power generation mechanism in the dynamic displacement detection unit, stores the energy for each measurement point in a capacitor, detects the amount of electrical energy stored within a unit business period for each measurement point every time the unit business period elapses, and estimates the dynamic displacement of the track at each measurement point by comparing the detected values of the electrical energy amounts for each unit business period for each measurement point.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When monitoring vibrations using multiple sensors installed at multiple measurement points on a structure and visualizing the structural deformation using modal analysis, it is necessary to synchronize the measurement data at each measurement point. Therefore, conventionally, multiple sensors are connected via wires to the same data logger, and multiple measurement data are input to the data logger in parallel.

[0006] However, in recent years, there has been a trend towards wirelessly connecting multiple sensors. For example, with the development of energy harvesting technologies such as vibration power generation, sensors are becoming powerless, eliminating the need for AC power sources, and thus wireless sensors are becoming more common. As a result, there is a problem in that it is difficult to synchronously process vibrations or deformations when measurement data detected by multiple sensors is aggregated as wireless signals.

[0007] This disclosure is made in view of the above circumstances and aims to provide a structural analysis system and a structural analysis method that can perform modal analysis by synchronizing multiple vibration signals detected by multiple wireless sensors. [Means for solving the problem]

[0008] This disclosure has been made to solve the above-mentioned problems, and one aspect of this disclosure is a structural analysis system comprising: a plurality of vibration sensors installed at different locations on a structure to detect vibrations of the structure; a synchronization unit that synchronizes a plurality of vibration signals indicating vibrations detected by the plurality of vibration sensors; and an analysis unit that performs modal analysis of the structure based on each of the plurality of vibration signals synchronized by the synchronization unit.

[0009] Another aspect of the present disclosure is a structural analysis method comprising: detecting vibrations of a structure using a plurality of vibration sensors installed at different locations on the structure; synchronizing a plurality of vibration signals indicating vibrations detected by the plurality of vibration sensors; and performing a modal analysis of the structure based on each of the synchronized plurality of vibration signals. [Effects of the Invention]

[0010] According to one aspect of the present invention, modal analysis can be performed by synchronizing multiple vibration signals detected by multiple wireless sensors. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view showing an overview of the structure in the embodiment. [Figure 2] This is a block diagram showing an example of the functional configuration of the structural analysis system 1 in the embodiment. [Figure 3] This figure shows an example of another configuration of the structural analysis system 1 of the embodiment. [Figure 4] This figure shows an example of another configuration of the structural analysis system 1 of the embodiment. [Figure 5] Figure 5 shows an example of a structural analysis method using the structural analysis system 1 in the embodiment. [Figure 6] This diagram illustrates the vibration signals in the embodiment, where (A) shows the distance between the excitation point X0 and the measurement point X1, (B) shows the vibration signal indicating the vibration transmitted to the rail section 112, and (c) shows the vibration signal indicating the vibration of the railway bridge 100. [Figure 7] The following is another diagram illustrating the vibration signals in the embodiment, where (A) shows the distance between the excitation point X0 and the measurement points X1 and X2, (B) shows the vibration signal indicating the vibration transmitted to the measurement point X1, and (c) shows the vibration signal indicating the vibration transmitted to the measurement point X2. [Figure 8]The following is another diagram illustrating the vibration signals in the embodiment, where (A) shows the distance between the excitation point X0 and the measurement points X1 and X2, (B) shows the vibration signal indicating the vibration transmitted to the measurement point X1, and (c) shows the vibration signal indicating the vibration transmitted to the measurement point X2. [Figure 9] This figure shows an example of a structural analysis method using the structural analysis system 1 in the embodiment. [Modes for carrying out the invention]

[0012] The structural analysis system and structural analysis method to which the present invention is applied will be described below with reference to the drawings.

[0013] Figure 1 is a perspective view showing an overview of the structure in the embodiment. The structural analysis system in this embodiment analyzes, for example, a railway bridge 100 as shown in Figure 1. The railway bridge 100 comprises, for example, a bridge girder section 102 and a bridge pier section 104. Multiple sleeper sections 110 and multiple rail sections 112 are provided on the bridge girder section 102. The multiple sleeper sections 110 are arranged in a line along the direction of railway travel. The multiple rail sections 112 are fixed to the multiple sleeper sections 110 by fastening structures for each pair of rail sections 112. In this embodiment, a single bridge girder section 102 is shown with two rows of sleeper sections 110 and two pairs of rail sections 112.

[0014] The structural analysis system in this embodiment includes a plurality of vibration sensors P1, P2, P3, P4, P5, and P6 installed near the fastening structure of the rail section 112. The vibration sensors P1, P2, P3, P4, P5, and P6 are a plurality of vibration sensors installed at different locations on the structure to detect vibrations of the structure.

[0015] In particular, each of the vibration sensors P1, P2, P3, P4, P5, and P6 detects a vibration signal indicating the vibration of the railway bridge 100 and a vibration signal indicating the vibration transmitted by the rail part 112 of the railway bridge 100. Each of the vibration sensors P1, P2, P3, P4, P5, and P6 detects a vibration signal indicating vibration in a first frequency band and vibration in a second frequency band higher than the first frequency band. The first frequency band is a frequency band corresponding to the vibration of the first mode of the railway bridge 100, and the second frequency band is a frequency band corresponding to the vibration transmitted by the rail part 112 of the railway bridge 100.

[0016] In the embodiment, the railway bridge 100 is taken as the analysis object, but it is not limited thereto, and any structure may be used as long as a plurality of vibration sensors such as bridges, roads, and buildings other than railways are installed for modal analysis.

[0017] FIG. 2 is a block diagram showing an example of the functional configuration of the structure analysis system 1 in the embodiment. The structure analysis system 1 includes, for example, a plurality of vibration sensors 10-1, 10-2, 10-3,... (hereinafter, referred to as "vibration sensors 10" in general), signal processing units 12-1, 12-2, 12-3,... (hereinafter, referred to as "signal processing units 12" in general), communication units 14-1, 14-2, 14-3,... (hereinafter, referred to as "communication units 14" in general), a server processing unit 20, a synchronization unit 22, an analysis unit 24, and an output unit 26.

[0018] The vibration sensor 10 corresponds to each of the vibration sensors P1, P2, P3, P4, P5, and P6 described above. When the vibration sensor 10 detects the vibration of the railway bridge 100, it generates a vibration signal and outputs it to the signal processing unit 12. The vibration signal includes identification information for identifying the vibration sensor 10. At least one of position information indicating the position of the vibration sensor 10 and time information indicating the detection time of the vibration may be added to the vibration signal.

[0019] The signal processing unit 12 performs edge computing, such as a single-port computer. Each signal processing unit 12 is provided in conjunction with each vibration sensor 10. The signal processing unit 12 performs predetermined processing on the vibration signal output from the vibration sensor 10 and outputs it to the communication unit 14.

[0020] The communication unit 14 is a communication device that has the function of transmitting wireless signals. Each of the communication units 14 is provided in correspondence with each of the signal processing units 12. The communication unit 14 transmits the vibration signals output from the signal processing unit 12 as wireless signals. As a result, multiple vibration signals detected by the vibration sensor 10 are transmitted to the server processing unit 20.

[0021] The vibration sensor 10, signal processing unit 12, and communication unit 14 may be integrated into a single unit, or they may be separate units.

[0022] The server processing unit 20 functions as an acquisition unit that acquires vibration signals from each of the communication units 14. The server processing unit 20 stores the vibration signal for each vibration sensor 10 based on the identification information attached to the vibration signal.

[0023] The synchronization unit 22 synchronizes multiple vibration signals indicating vibrations detected by multiple vibration sensors 10. The vibration signals that the synchronization unit 22A synchronizes are vibration signals indicating vibrations of the railway bridge 100. Due to the positions of the vibration sensors 10, the communication period of the wireless signals, etc., the multiple vibration signals are out of sync in time. In response to this, the synchronization unit 22 corrects the time difference between the vibration signals by shifting the vibration signals in time, thereby aligning the multiple vibration signals in time.

[0024] The synchronization unit 22 may acquire multiple vibration signals from multiple vibration sensors 10 and synchronize the multiple vibration signals based on at least one of the installation positions of the multiple vibration sensors 10, the distance from the multiple vibration sensors 10 to the synchronization unit 22, and the transmission speed of the vibration signals. The installation positions of the multiple vibration sensors 10 may be acquired, for example, by pre-stored position information of the vibration sensors 10, or by acquiring position information attached to the vibration signals. The distance from the multiple vibration sensors 10 to the synchronization unit 22 is the distance over which the vibration signals transmitted from the vibration sensors 10 are transmitted, and any distance information that allows for the calculation of the time difference between vibration signals is acceptable. The transmission speed of the vibration signals is the transmission speed of the wireless signals, and any speed information that allows for the calculation of the time difference between vibration signals is acceptable.

[0025] The analysis unit 24 performs modal analysis of the railway bridge 100 based on each of the multiple vibration signals synchronized by the synchronization unit 22. The vibration signals that the analysis unit 24 performs modal analysis on are vibration signals that indicate the vibration of the railway bridge 100. By performing modal analysis on the vibration signals corresponding to each of the vibration sensors 10, the analysis unit 24 creates analysis results that show how the railway bridge 100 is deformed in the vicinity of each of the vibration sensors 10. The analysis unit 24 outputs the analysis results from the output unit 26.

[0026] The output unit 26 outputs the analysis results. The output unit 26 may be a communication device that transmits the analysis results to a terminal device or data storage device. The output unit 26 may also be a display device that displays the analysis results.

[0027] Figure 3 shows an example of another configuration of the structural analysis system 1 according to the embodiment. The synchronization unit 22A may update time information by communicating with the NTP (Network Time Protocol) server 30 and synchronize multiple vibration signals based on the updated time. The synchronization unit 22A may function as an NTP client and update its own time information. Alternatively, each of the vibration sensors 10, or the signal processing unit 12 or the communication unit 14, may function as an NTP client and update the time information attached to the vibration signals. The synchronization unit 22A synchronizes multiple vibration signals based on the time updated by NTP.

[0028] Figure 4 shows an example of another configuration of the structural analysis system 1 according to the embodiment. The structural analysis system 1 may have multiple vibration sensors 10 perform multi-hop communication to transmit vibration signals to the server processing unit 20. For example, multi-hop communication is performed in the order of vibration sensors 10-1, 10-2, 10-3, 10-4, 10-5, and 10-6, and the vibration signals detected by vibration sensors 10-1, 10-2, 10-3, 10-4, 10-5, and 10-6 are transmitted to the server processing unit 20 via the signal processing unit 12 and the communication unit 14. Each vibration signal is accompanied by time information indicating the time when vibration was detected by the respective vibration sensor 10.

[0029] The synchronization unit 22B acquires multiple vibration signals from multiple vibration sensors 10 via multi-hop communication and synchronizes the multiple vibration signals based, for example, on time information attached to the multiple vibration sensors 10. The synchronization unit 22B may also synchronize the multiple vibration signals based on at least one of the following: the installation positions of the multiple vibration sensors 10, the transmission distance of the wireless signal from the multiple vibration sensors 10 to the synchronization unit 22, and the transmission speed of the vibration signal.

[0030] Figure 5 shows an example of a structural analysis method using the structural analysis system 1 in the embodiment. This structural analysis method may be performed by a computer (information processing device) including a server processing unit 20, a synchronization unit 22, and an analysis unit 24 connected to the vibration sensor 10. First, multiple vibration signals detected by the vibration sensor 10 are acquired (step S100). Next, the synchronization unit 22 (including synchronization units 22A and 22B) synchronizes the vibration signals indicating the vibration of the railway bridge 100 (step S102). Next, the analysis unit 24 performs modal analysis using each of the synchronized multiple vibration signals (step S104). Next, the output unit 26 outputs the analysis results corresponding to each of the multiple vibration signals (step S106).

[0031] As described above, the structural analysis system 1 includes a plurality of vibration sensors 10 installed at different locations on the structure to detect vibrations of the structure, a synchronization unit 22 that synchronizes a plurality of vibration signals indicating vibrations detected by the plurality of vibration sensors 10, and an analysis unit 24 that performs modal analysis of the structure based on each of the plurality of vibration signals synchronized by the synchronization unit 22. This allows for synchronized vibration signals from a plurality of wireless vibration sensors 10 to perform modal analysis.

[0032] In the structural analysis system 1, the synchronization unit 22 acquires multiple vibration signals from multiple vibration sensors 10 and synchronizes the multiple vibration signals based on at least one of the installation positions of the multiple vibration sensors 10, the distance from the multiple vibration sensors 10 to the server processing unit 20, and the transmission speed of the vibration signals, thereby enabling modal analysis by synchronizing the vibration signals from the multiple vibration sensors 10.

[0033] In the structural analysis system 1, the synchronization unit 22 updates time information by communicating with the NTP server 30, and synchronizes multiple vibration signals based on the updated time, thereby enabling modal analysis by synchronizing the vibration signals of multiple vibration sensors 10. Furthermore, in the structural analysis system 1, even if multiple vibration sensors 10 perform multi-hop communication with other vibration sensors 10, and the server processing unit 20 receives a vibration signal from at least one of the multiple vibration sensors 10, it can still synchronize the vibration signals of the multiple vibration sensors 10 and perform modal analysis.

[0034] The following describes how, in the structural analysis system 1 described above, the vibration sensor 10 detects vibration signals indicating vibrations of the railway bridge 100 and vibration signals indicating vibrations transmitted by the rail section 112 of the railway bridge 100, and the synchronization unit 22 synchronizes the vibration signals indicating vibrations of the railway bridge 100 using the vibration signals indicating vibrations transmitted by the rail section 112.

[0035] In the structural analysis system 1 of this embodiment, the synchronization error of signals due to NTP or multi-hop communication is generally known to be around a few microseconds to a few tens of milliseconds. If we take 10 milliseconds as a typical value for the synchronization error, then 10 milliseconds corresponds to 100 Hz in terms of frequency. That is, at 100 Hz, an error of 2π occurs, so effectiveness is not guaranteed only when the Nyquist frequency is 100 Hz or less. For example, when performing modal analysis, it is generally desirable to keep the error in phase angle within approximately 10 degrees.

[0036] Furthermore, assuming that the errors of the multiple vibration sensors 10 follow a normal distribution, and the maximum error is 20 degrees, the median will be 10 degrees. Therefore, if a phase error of 20 degrees is acceptable for the maximum vibration signal, then at 20 / 360 times 100 Hz, i.e., 5.56 Hz or less, the maximum phase error will be 20 degrees and the average phase error will be 10 degrees.

[0037] Depending on the shape and size of the railway bridge 100, the primary mode of the railway bridge 100 is approximately a few Hz to 10 Hz. Therefore, if the error in the vibration signal is approximately 1 to 10 ms, modal analysis can be performed to monitor the deformation of the railway bridge 100. In other words, if the transmission delay due to multiple vibration signals detected by multiple vibration sensors 10 is approximately 10 ms, and the primary mode of the railway bridge 100 is 10 Hz, the vibration of the railway bridge 100 can be monitored by modal analysis. Thus, even if multiple vibration sensors 10 are made wireless, as in the structural analysis system 1, and vibration signals are acquired wirelessly, the deformation of the railway bridge 100 can be monitored by synchronizing the multiple wireless signals.

[0038] When monitoring the deformation of the railway bridge 100 as in the embodiment, the structural analysis system 1 not only transmits vibration signals wirelessly, but also synchronizes vibration signals caused by vibrations of the railway bridge 100 using vibrations transmitted by the rail section 112. For example, any vibration in the rail section 112, such as vibrations that originate and propagate from outside the bridge section, may be used to synchronize vibration signals caused by vibrations of the railway bridge 100. Vibrations that originate and propagate from outside the bridge section are, for example, short-term, high-amplitude impulsive vibrations that occur when a train travels over rail joints before or after entering the railway bridge 100.

[0039] Since the rail section 112 contains iron, and there are reports that the vibration propagation speed of iron is 5000 m / s, which is more than 10 times the propagation speed in normal air (340 m / s), we consider using the vibration signal corresponding to the vibration transmitted by the rail section 112 as a synchronization signal. For example, consider a method of using impulsive vibrations emitted from outside the section of the railway bridge 100 as a synchronization signal. Assuming a railway bridge 100 with a distance of 20 m between the bridge piers 104, the impulsive vibrations transmitted to the rail section 112 propagate between the bridge piers 104 in 20 / 5000 = 4 ms. If the coordinate position of the vibration sensor 10 (vibration measurement point) is known, higher synchronization accuracy can be obtained by synchronizing the impulsive vibration signal and then shifting the vibration signal by a time calculated backward from the distance between the vibration sensors 10.

[0040] If the position of the vibration sensor 10 is unknown, and the error of the vibration signal transmitted to the rail section 112 is 4ms, this corresponds to 250Hz. Multiplying 250Hz by 20 / 360 gives 13.89Hz. If the vibration of the railway bridge 100 is 13.89Hz or less, the 250Hz vibration signal can be used as a synchronization signal. The primary mode of an existing railway bridge 100 with a distance of approximately 20m between bridge piers 104 is about 10Hz, although this varies depending on the shape of the railway bridge 100, and is below 13.89Hz, so the 250Hz vibration signal can be used as a synchronization signal. Therefore, by using wireless signal synchronization and the vibration of the rail section 112, it is possible to synchronize the vibration signals indicating the vibration of the railway bridge 100 and perform deformation monitoring of the railway bridge 100 using multiple vibration sensors 10.

[0041] Figure 6 is a diagram illustrating the vibration signals in the embodiment, where (A) shows the distance between the excitation point X0 and the measurement point X1, (B) shows the vibration signal indicating the vibration transmitted to the rail section 112, and (c) shows the vibration signal indicating the vibration of the railway bridge 100. For example, when an impulsive vibration is applied to the excitation point X0 in (A), the vibration sensor 10 at the measurement point X1 detects a vibration signal as shown in (B) at time Δt1. When the entire railway bridge 100 is subjected to vibration at the excitation point X0 in (A), such as when a train passes over it, the vibration sensor 10 at the measurement point X1 detects a vibration signal as shown in (C) at time Δt1. The vibration signal shown in (B) has a slow propagation speed and a high frequency waveform, while the vibration signal shown in (C) has a fast propagation speed and a low frequency vibration. Note that Δt1 is the group delay, which is the time it takes for the vibration to propagate from the excitation point to the measurement point. Also, the vibration speed and Δt1 are inversely proportional.

[0042] Figure 7 is another diagram illustrating the vibration signals in the embodiment, where (A) shows the distance between the excitation point X0 and the measurement points X1 and X2, (B) shows the vibration signal indicating the vibration transmitted to measurement point X1, and (c) shows the vibration signal indicating the vibration transmitted to measurement point X2. For example, when an impulsive vibration is applied to the excitation point X0 at (A), a vibration signal as shown in (B) is detected by the vibration sensor 10 at measurement point X1 at time Δt1, and a vibration signal as shown in (C) is detected by the vibration sensor 10 at measurement point X2 at time Δt21. The period T1 between time Δt1 and time Δt2 is delayed by one wavelength (more than 360 degrees) from the vibration signal detected at measurement point X1, and even if one vibration signal is used as a synchronization signal, the discrepancy in the other vibration signal cannot be corrected.

[0043] Figure 8 is another diagram illustrating the vibration signals in the embodiment, where (A) shows the distance between the excitation point X0 and the measurement points X1 and X2, (B) shows the vibration signal indicating the vibration transmitted to measurement point X1, and (c) shows the vibration signal indicating the vibration transmitted to measurement point X2. For example, when the entire vibration of the railway bridge 100 is applied to the excitation point X0 at (A), a vibration signal as shown in (B) is detected by the vibration sensor 10 at measurement point X1 at time Δt1, and a vibration signal as shown in (C) is detected by the vibration sensor 10 at measurement point X2 at time Δt21. The period T2 between time Δt1 and time Δt2 is only a small difference from the vibration signals shown in (B) and (C), and for structures with a resonant frequency lower than this difference (angle), it can be considered equivalent in modal analysis. Therefore, the high-velocity vibration signals transmitted in the rail section 112 can be used to synchronize the low-velocity vibration signals that represent the overall vibration of the railway bridge 100.

[0044] Figure 9 shows an example of a structural analysis method using the structural analysis system 1 in the embodiment. This structural analysis method may be performed by a computer (information processing device) including a server processing unit 20, a synchronization unit 22, and an analysis unit 24 connected to the vibration sensor 10. First, a vibration signal is acquired by detecting the vibration transmitted by the rail section 112 detected by the vibration sensor 10 (step S200). The server processing unit 20 may process the vibration signal into an impulse-like signal by, for example, performing filtering on it. The vibration signal is acquired by detecting the vibration transmitted by the entire railway bridge 100 as detected by the vibration sensor 10 (step S202). Next, the synchronization unit 22 (including synchronization units 22A and 22B) synchronizes the vibration signal indicating the vibration of the railway bridge 100 acquired in step S202 using multiple vibration signals based on the vibration transmitted to the rail section 112 acquired in step S200 (step S204). The synchronization unit 22 calculates the waveform shift amount of each vibration sensor 10 so as to match the timing of the multiple vibration signals acquired in step S200, and performs a process to shift the vibration signal indicating the vibration of the railway bridge 100 by the calculated waveform shift amount. Next, the analysis unit 24 performs modal analysis using each of the synchronized multiple vibration signals (step S206). Next, the output unit 26 outputs the analysis results corresponding to each of the multiple vibration signals (step S208).

[0045] As described above, according to the structural analysis system 1 of this embodiment, the vibration sensor 10 detects vibration signals indicating vibrations of the railway bridge 100 and vibration signals indicating vibrations transmitted by the rail section 112 of the railway bridge 100, and the synchronization unit 22 can synchronize the vibration signals indicating vibrations of the railway bridge 100 using the vibration signals indicating vibrations transmitted by the rail section 112.

[0046] Furthermore, according to the structural analysis system 1, the vibration sensor 10 detects vibration signals indicating vibrations in a first frequency band and vibrations in a second frequency band higher than the first frequency band, and the synchronization unit 22 can synchronize the vibration signals indicating vibrations in the first frequency band using the vibration signals indicating vibrations in the second frequency band. Thus, the synchronization unit 22 can synchronize the vibration signals indicating vibrations of the railway bridge 100 using the vibration signals indicating vibrations transmitted by the rail section 112. The structural analysis system 1 of this embodiment focuses on a novel aspect: it can synchronize the vibrations of the railway bridge 100 using the vibration propagation of an object with a high vibration propagation speed (for example, the iron rail section 112). In other words, it takes into account the guaranteed range of phase angle deviation in the vibration signal necessary for performing modal analysis on the railway bridge 100. Furthermore, according to the structural analysis system 1 of this embodiment, by using multi-hop communication between vibration sensors 10, for example, modal analysis can be performed based on vibrations detected by vibration sensors 10 even in locations where wireless communication between the vibration sensors 10 and the server processing unit 20 is not possible. Furthermore, according to the structural analysis system 1, even if the vibration sensor 10 utilizes energy harvesting technology activated by vibration, it can be activated using vibrations generated when the train is running, and modal analysis can be performed using vibration signals based on the vibrations of the rail section 112 and vibration signals based on the vibrations of the railway bridge 100. Furthermore, according to the structural analysis system 1, vibration sensors 10 can be added to the railway bridge 100 as an afterthought, and the number of vibration sensors 10 can be eliminated. Furthermore, according to the structural analysis system 1, it is also possible to first acquire vibration signals based on the vibration of the railway bridge 100, and then acquire vibration signals based on the vibration of the rail section 112, thereby synchronizing the vibration signals based on the vibration of the railway bridge 100.

[0047] While embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure. [Explanation of symbols]

[0048] 1. Structural Analysis System 10, 10-1, 10-2, 10-3, 10-4, 10-5, 10-6 vibration sensor 12, 12-1, 12-2, 12-3 Signal Processing Unit 14, 14-1, 14-2, 14-3 Communications Department 20 Server Processing Unit 22, 22A, 22B synchronous section 24 Analysis Department 26 Output section 30 NTP servers 100 Railway Bridges 102 Bridge girder section 104 Bridge pier section 110 Sleeper section 112 Rail section P1, P2, P3, P4, P5, P6 Vibration Sensors

Claims

1. Multiple vibration sensors are installed at different locations on the structure to detect vibrations of the structure, A synchronization unit that synchronizes multiple vibration signals indicating vibrations detected by the multiple vibration sensors, An analysis unit that performs modal analysis of the structure based on each of the plurality of vibration signals synchronized by the synchronization unit, A structural analysis system equipped with [features / equipment].

2. The structural analysis system according to claim 1, wherein the synchronization unit acquires multiple vibration signals from multiple vibration sensors and synchronizes the multiple vibration signals based on at least one of the installation positions of the multiple vibration sensors, the distance from the multiple vibration sensors to the acquisition unit, and the transmission speed of the vibration signals.

3. The structural analysis system according to claim 2, wherein the synchronization unit updates time information by communicating with an NTP server and synchronizes the plurality of vibration signals based on the updated time.

4. The aforementioned plurality of vibration sensors perform multi-hop communication with other vibration sensors. The acquisition unit receives vibration signals from at least one of the multiple vibration sensors. The structural analysis system according to claim 2 or 3.

5. The aforementioned structure is a railway bridge, The vibration sensor detects vibration signals indicating vibrations of the railway bridge and vibration signals indicating vibrations transmitted by the rail section of the railway bridge. The synchronization unit synchronizes vibration signals indicating vibrations of the railway bridge using vibration signals indicating vibrations transmitted by the rail section. The structural analysis system according to claim 1.

6. The aforementioned structure is a railway bridge, The vibration sensor detects vibration signals indicating vibrations in a first frequency band and vibrations in a second frequency band higher than the first frequency band. The synchronization unit synchronizes the vibration signal indicating vibration in the first frequency band using the vibration signal indicating vibration in the second frequency band. The structural analysis system according to claim 1.

7. The first frequency band is the frequency band corresponding to the first mode vibration of the railway bridge, The second frequency band is a frequency band corresponding to vibrations transmitted by the rail section of the railway bridge. The structural analysis system according to claim 6.

8. The steps include: detecting vibrations of a structure using multiple vibration sensors installed at different locations on the structure; The steps include synchronizing multiple vibration signals indicating vibrations detected by the multiple vibration sensors, The steps include performing a modal analysis of the structure based on each of the synchronized plurality of vibration signals, A structural analysis method that includes [the following].

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