Structural evaluation system and structural evaluation method

Abstract

To provide a structure evaluation system and a structure evaluation method capable of improving the evaluation accuracy of structures.SOLUTION: A structure evaluation system according to an embodiment has an impact application unit, a plurality of sensors, a position locating unit, and an evaluation unit. The impact application unit applies an impact to a second region different from a first region of a structure, on which the impact is applied by a traveling portion of a vehicle traveling on the structure. The plurality of sensors detect elastic waves generated in the structure. The position locating unit locates a position of the source of the elastic waves based on the elastic waves detected by each of the plurality of sensors. The evaluation unit evaluates the state of deterioration of the structure based on the position location result of the position locating unit.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] Embodiments of the present invention relate to a structure evaluation system and a structure evaluation method.

Background Art

[0002] By installing sensors on the surface of a structure such as a bridge, elastic waves generated inside the structure can be detected. Furthermore, by installing a plurality of sensors on the surface of the structure, the position of the elastic wave source (hereinafter referred to as the "elastic wave source") can be calibrated based on the difference in the arrival times of the elastic waves detected by each sensor. Elastic waves are also generated inside the structure when an impact is applied to the surface of the structure from the outside. Therefore, the position of the elastic wave source can be calibrated.

[0003] When there is damage in the propagation path of elastic waves inside the structure, the propagation of elastic waves is hindered. In such a case, the accuracy of the calibration result of the elastic wave source decreases. When an impact uniformly applied spatially, such as the impact of raindrops on the road surface during rainfall, is applied to the surface of the structure and elastic waves are detected by a sensor installed opposite, the density of the elastic wave source is observed to decrease in the region having damage inside. Utilizing such characteristics, damage inside the structure can be detected.

[0004] When using a method of applying a uniformly applied impact to the surface of the structure, if there is no damage inside the structure, the distribution of the elastic wave sources becomes uniform. In this method, it is premised that a uniformly applied impact is applied to the surface of the structure. However, in order to apply an impact uniformly to the road surface, it is necessary to use natural phenomena such as raindrops or to strike the road surface over a wide area. For that purpose, it is necessary to carry out lane regulation or the like, which may impair the convenience of users. On the other hand, as a means of applying an impact to a limited range without lane regulation, the wheel load of a traveling vehicle can be considered. However, since the elastic wave sources generated by the wheel load are concentrated particularly at the rut portion, the propagation path of the elastic waves passing through the inside of the structure is biased, and there are cases where internal damage cannot be correctly evaluated.

Prior Art Documents

[0005] [Patent Document 1] International Publication No. 2017 / 217034 [Patent Document 2] Japanese Patent Publication No. 2015-219076 [Patent Document 3] U.S. Patent Application Publication No. 2009 / 0173137 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The problem that this invention aims to solve is to provide a structural evaluation system and a structural evaluation method that can improve the accuracy of structural evaluation. [Means for solving the problem]

[0007] The structural evaluation system of this embodiment includes an impact application unit, a plurality of sensors, a positioning unit, and an evaluation unit. The impact application unit is mounted on the rear of a vehicle traveling on the structure, and the first region of the structure to which the vehicle's driving part has impacted is There is no overlap. Apply an impact to a different second region. Multiple sensors, The first region of the structure that was impacted by the running section of the vehicle and the second region of the structure that was impacted by the impact-applying section The elastic waves generated are detected. The position determination unit determines the position of the source of the elastic waves based on the elastic waves detected by each of the plurality of sensors. The evaluation unit determines the position based on the position determination result by the position determination unit. Regarding both the first and second regions The deterioration state of the structure is evaluated. The impact-applying unit is a water-spraying device that applies impact to the second area by spraying water. The range of water sprayed by the water-spraying device is wider than the distance between the running parts of the vehicle. [Brief explanation of the drawing]

[0008] [Figure 1] A diagram illustrating the evaluation methods of conventional structural evaluation systems. [Figure 2]A diagram illustrating the method for generating elastic waves in the first embodiment. [Figure 3] Figure (1) shows an example of a towed vehicle used in the first embodiment. [Figure 4] Figure 3 shows the location of the additional elastic wave source when using the towed vehicle shown. [Figure 5] Figure (2) shows an example of a towed vehicle used in the first embodiment. [Figure 6] Figure 5 shows the location of the additional elastic wave source when using the towed vehicle shown. [Figure 7] A diagram showing the configuration of the structural evaluation system in the first embodiment. [Figure 8] A schematic block diagram illustrating the functions of the signal processing unit in the first embodiment. [Figure 9] A sequence diagram showing the flow of the deterioration state evaluation process by the structural evaluation system in the first embodiment. [Figure 10] A diagram illustrating the method for generating elastic waves in the second embodiment. [Figure 11] This diagram shows the location of additional elastic wave sources when watering is performed intermittently by a sprinkler system. [Figure 12] This diagram shows the location of additional elastic wave sources when water is continuously sprayed using a sprinkler system. [Figure 13] This diagram shows the location of additional elastic wave sources when water is sprayed intermittently by a watering system, including outside the tread. [Figure 14] This diagram shows the location of additional elastic wave sources when water is continuously sprayed by a watering system, including the area outside the tread. [Modes for carrying out the invention]

[0009] The structural evaluation system and structural evaluation method of the embodiment will be described below with reference to the drawings. (overview) In the structural evaluation system according to the embodiment, in a method of evaluating damage inside a structure by using a traveling vehicle that travels on the surface of the structure (hereinafter referred to as "road surface"), it is a system that can improve the evaluation accuracy of the structure more than before. First, the conventional evaluation method will be described using FIG. 1.

[0010] FIG. 1 is a diagram for explaining the evaluation method of a conventional structural evaluation system. Under the situation shown in FIG. 1, a load is applied to the road surface due to the contact between the traveling part W (for example, a tire) of the vehicle and the road surface. The load on the road surface is caused by the traveling part W of the vehicle. Thus, the traveling part W of the vehicle imparts an impact to the road surface. As a result, elastic waves are generated inside the structure 50. The location where the traveling part W of the vehicle contacts the road surface becomes the elastic wave source SR. On the other hand, no impact is applied to the area of the road surface that the traveling part W of the vehicle has not passed through. The area where the traveling part W of the vehicle contacts the road surface corresponds to the first area, and the area where the traveling part W of the vehicle does not contact the road surface corresponds to the second area.

[0011] When the elastic waves generated by the traveling part W of the vehicle are detected by one or more sensors S installed on the lower surface of the structure 50, a decrease in the density of the elastic wave source SR is observed in the area having damage inside the structure 50. By utilizing such characteristics, the damage inside the structure 50 can be detected. That is, it is possible to evaluate the presence or absence of damage in the passage range of the wave line WL when the elastic waves generated by the traveling part W of the vehicle propagate to one or more sensors S.

[0012] FIG. 1(A) shows the wave line distribution when the traveling part W of the vehicle traveling on the road surface and the structure 50 are viewed from the side, and FIG. 1(B) shows the wave line distribution when the traveling part W of the vehicle traveling on the road surface and the structure 50 are viewed from the front. The arrow in FIG. 1(A) represents the vehicle traveling direction. The wave line distribution represents the distribution of a plurality of wave lines WL.

[0013] Since the running part W of the vehicle travels in the vehicle traveling direction, an elastic wave source SR continuously exists in the vehicle traveling direction. Therefore, as shown in Fig. 1(A), it can be seen that the wave lines WL are evenly distributed over a wide range. On the other hand, as shown in Fig. 1(B), the elastic waves caused by the running part W of the vehicle concentrate the elastic wave source SR at the wheel load position, which is the place where the running part W of the vehicle travels. Here, the wheel load position represents the position where a load is applied by the running part W of the vehicle. Therefore, it can be seen that the path of the elastic waves passing through the inside of the structure 50 is biased. As shown in Fig. 1(B), the distribution of the wave lines WL becomes sparse, and it can be seen that there are regions where the wave lines WL do not pass. In this case, even if there is damage in the region where the wave lines WL do not pass, it cannot be evaluated.

[0014] Therefore, in the structure evaluation system according to the present embodiment, an impact applying unit is provided to the vehicle so that the elastic wave generation method is devised to apply more intensive impacts to the road surface in the vehicle width direction, which is orthogonal to the vehicle traveling direction. The impact applying unit is a mechanism that applies an impact to the road surface separately from the running part W of the vehicle. As methods for generating elastic waves so that more intensive impacts are applied, there are methods of increasing the number of wheels in the vehicle width direction by using an impact applying unit equipped with wheels, methods of using an impact applying unit that sprays water, methods of using an impact applying unit that gives a blow, and methods of using an impact applying unit that performs laser irradiation. The merit of using such a method is that vehicle regulations are not required during inspection. Hereinafter, embodiments using each method will be described.

[0015] (First Embodiment) In the first embodiment, a configuration will be described in which a method of increasing the number of wheels in the vehicle width direction by using an impact applying unit equipped with wheels is used as a method for generating elastic waves so that more intensive impacts are applied. Figure 2 is a diagram illustrating the method of generating elastic waves in the first embodiment. As shown in Figure 2, in the first embodiment, an impact is applied to the road surface by increasing the number of wheels W1 so that the running section W of the vehicle and the wheels are not aligned with respect to the direction of vehicle travel. As a result, the elastic waves generated by the wheels W1 propagate inside the structure 50 and are detected by the sensor S. Since the elastic waves generated by the wheels W1 propagate along a different path than the elastic waves generated by the running section W of the vehicle, it can be seen that a dashed line WL has been added to the new path.

[0016] When the wheels are aligned in the direction of vehicle travel, the elastic sources are lined up, causing interference between elastic waves and making the analysis complex. Therefore, as shown in Figure 2, offsetting the wheels in the direction of vehicle travel is advantageous for analyzing elastic waves. One way to add a new wheel W1 is to use a towed vehicle, as shown in Figure 3. Figure 3 is a diagram (part 1) showing an example of a towed vehicle used in the first embodiment. The towed vehicle is an example of an impact-applying unit 15. The towed vehicle shown in Figure 3 comprises a plurality of wheels W1, a towing unit 16, and a loading unit 17. The towed vehicle is towed by the vehicle. The towed vehicle and the vehicle are connected by the towing unit 16, and the towed vehicle can move as the vehicle moves.

[0017] The towed vehicle shown in Figure 3 has multiple wheels W1, with one wheel at the front and two at the rear in the vehicle width direction. Each wheel W1 is positioned so as not to overlap with others in the direction of vehicle travel, and further positioned so as not to overlap with the vehicle's running gear W in the direction of vehicle travel. The number of wheels W1 is not limited to the number shown in Figure 3, but as the number of wheels W1 increases, the contact area with the road surface increases, which may reduce the load applied to each contact surface. In this case, the wheel load applied to the contact surface is distributed and reduced. If the wheel load is not sufficient to generate elastic waves, the load can be increased by loading weights onto the loading section 17.

[0018] Figure 4 shows the locations of additional elastic wave sources when using the towed vehicle shown in Figure 3. Region A1 indicates the generation area of ​​elastic wave sources generated by the impact applied by the vehicle's running gear W. Region A2 indicates the generation area of ​​elastic wave sources generated by the impact applied by the towed vehicle's wheels W1. This configuration allows for the supplementation of areas where impact cannot be applied by the conventional vehicle's running gear W alone.

[0019] Figure 5 is a diagram (part 2) showing an example of a towed vehicle used in the first embodiment. The towed vehicle shown in Figure 5, like the one in Figure 3, is equipped with multiple wheels W1, a towing unit 16, and a loading unit 17. The towed vehicle shown in Figure 5 has an increased number of wheels W1 compared to the towed vehicle shown in Figure 3. In this case as well, each wheel W1 is positioned so as not to overlap with each other in the direction of vehicle travel, and further positioned so as not to overlap with the running section W of the vehicle in the direction of vehicle travel.

[0020] Figure 6 shows the position of the additional elastic wave source when using the towed vehicle shown in Figure 5. By using the configuration shown in Figure 6, it is possible to complement the region that cannot be impacted by the conventional vehicle's running section W alone, compared to the configuration shown in Figure 3.

[0021] Next, we will describe a configuration for evaluating the deterioration state of a structure using the impact-applying unit 15 as a towed vehicle, as shown in Figure 3 or Figure 5.

[0022] Figure 7 shows the configuration of the structural evaluation system 100 in the first embodiment. The structural evaluation system 100 is used to evaluate the soundness of the structure 50. In the following description, evaluation means determining the degree of soundness of the structure 50, that is, the state of deterioration of the structure 50, based on certain criteria.

[0023] In the following explanation, a concrete bridge is used as an example of structure 50, but structure 50 is not limited to bridges. Structure 50 can be any structure that generates elastic waves 11 in response to the occurrence or propagation of cracks, or external impacts (e.g., rain, artificial rain). For example, structure 50 may be bedrock. Note that bridges are not limited to structures built over rivers or valleys, but also include various structures built above ground level (e.g., elevated highways).

[0024] Damage that affects the evaluation of the deterioration state of structure 50 includes, for example, internal structural damage that obstructs the propagation of elastic waves 11, such as cracks, voids, and soiling. Here, cracks include longitudinal cracks, transverse cracks, and diagonal cracks. A longitudinal crack is a crack that occurs perpendicular to the road surface. A transverse crack is a crack that occurs horizontally to the road surface. A diagonal crack is a crack that occurs in directions other than horizontal and perpendicular to the road surface. Soiling is a deterioration in which concrete changes into a soil-like substance, mainly at the boundary between asphalt and concrete slabs.

[0025] The structural evaluation system 100 comprises an impact application unit 15, a plurality of sensors 20-1 to 20-n, a signal processing unit 30, and a structural evaluation device 40. Each of the plurality of sensors 20-1 to 20-n and the signal processing unit 30 are connected to each other via wired communication. The signal processing unit 30 and the structural evaluation device 40 are connected to each other via wired or wireless communication. In the following description, sensors 20-1 to 20-n will be referred to as sensor 20 unless otherwise distinguished. Sensors 20-1 to 20-n correspond to the sensors S shown in Figures 1 and 2.

[0026] The impact-applying unit 15 is a towed vehicle pulled by the vehicle 10. The impact-applying unit 15 has the configuration shown in Figure 3 or Figure 5, for example. The impact-applying unit 15 moves in accordance with the movement of the vehicle 10 and applies an impact to the road surface through contact between the road surface and the wheels W1.

[0027] Sensor 20 has a piezoelectric element and detects elastic waves 11 generated from inside the structure 50. Sensor 20 is installed in a position on the surface of the structure 50 where it can detect elastic waves 11. For example, sensor 20 is installed on one of the surfaces: the road surface, the side surface, or the bottom surface. Sensor 20 converts the detected elastic waves 11 into an electrical signal. In the following description, the case where sensor 20 is installed on the bottom surface of the structure 50 will be used as an example.

[0028] The sensor 20 uses, for example, a piezoelectric element with sensitivity in the range of 10 kHz to 1 MHz. Sensors 20 can be of any type, such as a resonant type with a resonance peak within the frequency range, or a broadband type with suppressed resonance. The sensor 20 can detect elastic waves 11 using various methods, such as a voltage output type, a resistance change type, or a capacitance type, and any of these detection methods is acceptable.

[0029] An acceleration sensor may be used instead of sensor 20. In this case, the acceleration sensor detects the elastic waves 11 generated inside the structure 50. The acceleration sensor then converts the detected elastic waves 11 into an electrical signal by performing the same processing as sensor 20.

[0030] Between the sensor 20 and the signal processing unit 30, for example, an amplifier and an A / D converter (not shown) are provided. The amplifier amplifies the electrical signal output from the sensor 20. The amplifier outputs the amplified electrical signal to the A / D converter. The amplifier amplifies the electrical signal to a degree that can be processed by the A / D converter, for example. The A / D converter quantizes the amplified electrical signal and converts it into a digital signal. The A / D converter outputs the digital signal to the signal processing unit 30.

[0031] The signal processing unit 30 receives the digital signal output from the A / D converter as input. The signal processing unit 30 performs signal processing on the input digital signal. The signal processing performed by the signal processing unit 30 includes, for example, noise reduction and parameter extraction. The signal processing unit 30 generates transmission data including the digital signal after signal processing. The signal processing unit 30 outputs the generated transmission data to the structural evaluation device 40.

[0032] The signal processing unit 30 is configured using analog or digital circuits. Digital circuits can be implemented, for example, by an FPGA (Field Programmable Gate Array) or a microcomputer. Digital circuits may also be implemented by a dedicated LSI (Large-Scale Integration). Furthermore, the signal processing unit 30 may incorporate non-volatile memory such as flash memory or removable memory.

[0033] Figure 8 is a schematic block diagram showing the functions of the signal processing unit 30 in the first embodiment. The signal processing unit 30 includes a waveform shaping filter 301, a gate generation circuit 302, an arrival time determination unit 303, a feature extraction unit 304, a transmission data generation unit 305, a memory 306, and an output unit 307.

[0034] The waveform shaping filter 301 removes noise components outside a predetermined bandwidth from the input digital signal. The waveform shaping filter 301 is, for example, a digital bandpass filter (BPF). The waveform shaping filter 301 outputs the digital signal after noise component removal (hereinafter referred to as the "noise-removed signal") to the gate generation circuit 302 and the feature extraction unit 304.

[0035] The gate generation circuit 302 receives the noise-removed signal output from the waveform shaping filter 301 as input. The gate generation circuit 302 generates a gate signal based on the input noise-removed signal. The gate signal indicates whether or not the waveform of the noise-removed signal is sustained.

[0036] The gate generation circuit 302 is implemented, for example, by an envelope detector and a comparator. The envelope detector detects the envelope of the denoised signal. The envelope is extracted, for example, by squaring the denoised signal and performing a predetermined process (for example, processing using a low-pass filter or a Hilbert transform) on the squared output value. The comparator determines whether the envelope of the denoised signal is above a predetermined threshold.

[0037] The gate generation circuit 302 outputs a first gate signal to the arrival time determination unit 303 and the feature extraction unit 304, indicating that the waveform of the noise-removed signal is continuing, when the envelope of the noise-removed signal exceeds a predetermined threshold. On the other hand, the gate generation circuit 302 outputs a second gate signal to the arrival time determination unit 303 and the feature extraction unit 304, indicating that the waveform of the noise-removed signal is not continuing, when the envelope of the noise-removed signal falls below a predetermined threshold.

[0038] The arrival time determination unit 303 receives a clock signal output from a clock source such as a crystal oscillator (not shown) and a gate signal output from the gate generation circuit 302 as input. The arrival time determination unit 303 determines the elastic wave arrival time using the input clock signal while the first gate signal is input. The arrival time determination unit 303 outputs the determined elastic wave arrival time as time information to the transmission data generation unit 305. The arrival time determination unit 303 does not perform any processing while the second gate signal is input. Based on the signal from the clock source, the arrival time determination unit 303 generates cumulative time information from the time of power-on. Specifically, the arrival time determination unit 303 can be a counter that counts clock edges, and the value of the counter's register can be used as time information. The counter's register is determined to have a predetermined bit length.

[0039] The feature extraction unit 304 receives the denoised signal output from the waveform shaping filter 301 and the gate signal output from the gate generation circuit 302 as inputs. The feature extraction unit 304 extracts features from the denoised signal using the denoised signal input while the first gate signal is being input. The feature extraction unit 304 does not perform any processing while the second gate signal is being input. Features are information that indicates the characteristics of the denoised signal.

[0040] Features include, for example, the amplitude of the waveform [mV], the rise time of the waveform [usec], the duration of the gate signal [usec], the number of zero-crossing counts [times], the energy of the waveform [arb.], the frequency [Hz], and the RMS (Root Mean Square) value. The feature extraction unit 304 outputs parameters related to the extracted features to the transmission data generation unit 305. When outputting the parameters related to the features, the feature extraction unit 304 associates the sensor ID with the parameters related to the features. The sensor ID represents identification information for identifying the sensor 20 installed in the area of ​​the structure 50 that is subject to evaluation of its integrity (hereinafter referred to as the "evaluation area").

[0041] The amplitude of the waveform is, for example, the maximum amplitude value in the denoising signal. The rise time of the waveform is, for example, the time T1 from the start of the rising edge of the gate signal until the denoising signal reaches its maximum value. The duration of the gate signal is, for example, the time from the start of the rising edge of the gate signal until the amplitude becomes smaller than a preset value. The zero-crossing count is, for example, the number of times the denoising signal crosses a reference line passing through zero.

[0042] The energy of the waveform is, for example, the time integral of the squared amplitude of the denoised signal at each point in time. Note that the definition of energy is not limited to the above example; it may also be approximated using, for example, the waveform envelope. The frequency is the frequency of the denoised signal. The RMS value is, for example, the value obtained by squaring the amplitude of the denoised signal at each point in time and taking the square root.

[0043] The transmission data generation unit 305 receives the sensor ID, time information, and feature parameters as input. The transmission data generation unit 305 generates transmission data that includes the input sensor ID, time information, and feature parameters.

[0044] Memory 306 stores the data to be transmitted. Memory 306 is, for example, a dual-port RAM (Random Access Memory). The output unit 307 sequentially outputs the transmission data stored in the memory 306 to the structural evaluation device 40.

[0045] Returning to Figure 7, we continue the explanation. The structural evaluation device 40 includes a communication unit 41, a control unit 42, a storage unit 43, and a display unit 44. The communication unit 41 receives the transmission data output from the signal processing unit 30. The control unit 42 controls the entire structure evaluation device 40. The control unit 42 is composed of a processor such as a CPU (Central Processing Unit) and memory. By executing a program, the control unit 42 functions as an acquisition unit 421, an event extraction unit 422, a location determination unit 423, a distribution generation unit 424, and an evaluation unit 425.

[0046] Some or all of the functional units of the acquisition unit 421, event extraction unit 422, location determination unit 423, distribution generation unit 424, and evaluation unit 425 may be implemented by hardware such as an ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA, or by the cooperation of software and hardware. The program may be recorded on a computer-readable recording medium. A computer-readable recording medium is a non-temporary storage medium such as a flexible disk, magneto-optical disk, ROM, CD-ROM, or other portable media, or a hard disk built into a computer system. The program may be transmitted via a telecommunications line.

[0047] Some of the functions of the acquisition unit 421, event extraction unit 422, position determination unit 423, distribution generation unit 424, and evaluation unit 425 do not need to be pre-installed in the structural evaluation device 40, and may be realized by installing additional application programs in the structural evaluation device 40.

[0048] The acquisition unit 421 acquires various types of information. For example, the acquisition unit 421 acquires transmission data received by the communication unit 41. The acquisition unit 421 stores the acquired transmission data in the storage unit 43.

[0049] The event extraction unit 422 extracts transmission data for one event from the transmission data stored in the storage unit 43. An event represents an elastic wave generation event that occurred at the structure 50. In this embodiment, the elastic wave generation event is the passage of a vehicle 10 and a towed vehicle over the road surface. When one event occurs, multiple sensors 20 will detect elastic waves 11 at approximately the same time. That is, the storage unit 43 will store transmission data related to the elastic waves 11 detected at approximately the same time. Therefore, the event extraction unit 422 sets a predetermined time window and extracts all transmission data whose arrival time falls within the time window as transmission data for one event. The event extraction unit 422 outputs the extracted transmission data for one event to the positioning unit 423.

[0050] The time window range Tw may be determined using the elastic wave propagation velocity v in the target structure 50 and the maximum sensor interval dmax, such that Tw ≥ dmax / v. To avoid false detection, it is desirable to set Tw to the smallest possible value, so in practice, Tw = dmax / v can be used. The elastic wave propagation velocity v may be determined in advance.

[0051] The positioning unit 423 determines the position of the elastic wave source based on the sensor position information and the sensor ID and time information contained in each of the multiple transmission data extracted by the event extraction unit 422.

[0052] The sensor position information includes information about the installation location of the sensor 20, associated with the sensor ID. The sensor position information includes information about the installation location of the sensor 20, such as latitude and longitude, or horizontal and vertical distances from a reference position of the structure 50. The positioning unit 423 has the sensor position information stored in advance. The sensor position information may be stored in the positioning unit 423 at any time before the positioning unit 423 performs positioning of the elastic wave source.

[0053] Sensor position information may be stored in the memory unit 43. In this case, the position determination unit 423 acquires the sensor position information from the memory unit 43 at the time of position determination. A Kalman filter, least squares method, or the like may be used to determine the position of the elastic wave source. The position determination unit 423 outputs the position information of the elastic wave source obtained during the measurement period to the distribution generation unit 424.

[0054] The distribution generation unit 424 receives position information of multiple elastic wave sources output from the position determination unit 423 as input. The distribution generation unit 424 generates an elastic wave source distribution using the input position information of multiple elastic wave sources. The elastic wave source distribution represents a distribution that indicates the positions of the elastic wave sources. More specifically, the elastic wave source distribution is a distribution in which points indicating the positions of elastic wave sources are shown on virtual data representing the structure 50 to be evaluated, with the horizontal axis representing the distance in the direction of travel and the vertical axis representing the distance in the width direction. The distribution generation unit 424 generates an elastic wave source density distribution using the elastic wave source distribution. For example, the distribution generation unit 424 generates an elastic wave source density distribution by representing the positions of the elastic wave sources with a contour map.

[0055] The evaluation unit 425 evaluates the deterioration state of the structure 50 based on the elastic wave source density distribution generated by the distribution generation unit 424. For example, the evaluation unit 425 evaluates the region where the density of elastic wave sources is above a threshold in the elastic wave source density distribution as a healthy region, and the region where the density of elastic wave sources is below the threshold as a damaged region. The evaluation region is the region through which the dashed lines, which indicate the propagation path of elastic waves from the elastic wave source to each of the sensors 20, have passed. Therefore, the evaluation unit 425 evaluates the deterioration state of the structure within the evaluation region.

[0056] The storage unit 43 stores the transmitted data acquired by the acquisition unit 421. The storage unit 43 is configured using a storage device such as a magnetic hard disk drive or a semiconductor storage device.

[0057] The display unit 44 displays the evaluation results according to the control of the evaluation unit 425. Furthermore, the display unit 44 displays a group of dashed lines WL indicating the propagation path of elastic waves from the elastic wave source to each sensor 20, for example, by projection, according to the control of the evaluation unit 425. The display unit 44 is an image display device such as a liquid crystal display or an organic EL (Electro-Luminescence) display. The display unit 44 may also be an interface for connecting an image display device to the structural evaluation device 40. In this case, the display unit 44 generates a video signal for displaying the evaluation results and outputs the video signal to the image display device connected to it.

[0058] Figure 9 is a sequence diagram showing the flow of the deterioration state evaluation process by the structural evaluation system 100 in the first embodiment. The process in Figure 9 is executed in response to the vehicle 10 driving over the structure 50 to be evaluated. When a vehicle 10 travels over the structure 50 to be evaluated, the running gear W of the vehicle 10 and the wheels W1 of the towed vehicle come into contact with the road surface. This generates elastic waves 11 within the structure 50. Each of the multiple sensors 20 detects the elastic waves 11 generated within the structure 50 (step S101). Each of the multiple sensors 20 converts the detected elastic waves 11 into an electrical signal and outputs it to the signal processing unit 30 (step S102). The electrical signals output from each of the multiple sensors 20 are amplified by an amplifier (not shown). The amplified electrical signals are converted into digital signals by an A / D converter.

[0059] The signal processing unit 30 receives the digital signal output from the A / D converter. The arrival time determination unit 303 of the signal processing unit 30 determines the arrival time of each elastic wave 11 (step S103). Specifically, the arrival time determination unit 303 determines the elastic wave arrival time using the clock input while the first gate signal is input. The arrival time determination unit 303 outputs the determined elastic wave arrival time as time information to the transmission data generation unit 305. The arrival time determination unit 303 performs this process for all input digital signals.

[0060] The feature extraction unit 304 of the signal processing unit 30 extracts features from the denoised signal, which is a digital signal input while the first gate signal is input (step S104). The feature extraction unit 304 outputs parameters related to the extracted features to the transmission data generation unit 305. The transmission data generation unit 305 generates transmission data including the sensor ID, time information, and parameters related to the features (step S105). The output unit 307 sequentially outputs the transmission data to the structure evaluation device 40 (step S106).

[0061] The communication unit 41 of the structural evaluation device 40 receives the transmission data output from the signal processing unit 30. The acquisition unit 421 acquires the transmission data received by the communication unit 41. The acquisition unit 421 records the acquired transmission data in the storage unit 43 (step S107). The event extraction unit 422 extracts the transmission data for one event from the transmission data stored in the storage unit 43. The event extraction unit 422 outputs the extracted transmission data for one event to the position determination unit 423 and the distribution generation unit 424.

[0062] The position determination unit 423 determines the position of the elastic wave source based on the sensor ID and time information included in the transmitted data output from the event extraction unit 422 and the sensor position information that it has previously stored (step S108). Specifically, first the position determination unit 423 calculates the difference in arrival times of the elastic waves 11 to each of the multiple sensors 20. Next, the position determination unit 423 determines the position of the elastic wave source using the sensor position information and the information on the difference in arrival times.

[0063] The positioning unit 423 executes the process in step S108 each time that transmission data for one event is output from the event extraction unit 422 during the measurement period. This allows the positioning unit 423 to determine the positions of multiple elastic wave sources. The positioning unit 423 then outputs the position information of the multiple elastic wave sources to the distribution generation unit 424.

[0064] The distribution generation unit 424 generates an elastic wave source distribution using the position information of multiple elastic wave sources output from the position determination unit 423. Specifically, the distribution generation unit 424 generates an elastic wave source distribution by plotting the positions of the elastic wave sources indicated by the obtained position information of multiple elastic wave sources onto virtual data. The distribution generation unit 424 generates an elastic wave source density distribution by representing the generated elastic wave source distribution as a contour plot (step S109). The distribution generation unit 424 outputs the generated elastic wave source density distribution to the evaluation unit 425.

[0065] The evaluation unit 425 evaluates the deterioration state of the structure 50 using the elastic wave source density distribution output from the distribution generation unit 424 (step S110). The evaluation unit 425 outputs the evaluation results to the display unit 44. The display unit 44 displays the evaluation results output from the evaluation unit 425 (step S112). For example, the display unit 44 may display the corrected elastic wave source density distribution as an evaluation result, or it may display areas considered to be damaged areas in a different display manner from other areas. Furthermore, the evaluation unit 425 may display a group of dashed lines WL, which indicate the propagation path of elastic waves from the elastic wave source to each sensor 20, on the display unit 44 using a projection method, based on the elastic wave source determined by the position determination unit 423 and the installation position information of each sensor 20. This makes it possible to display, for example, the group of dashed lines WL shown in Figure 2. The evaluation unit 425 may also display the group of dashed lines WL in three dimensions.

[0066] The structure evaluation system 100 configured as described above makes it possible to improve the accuracy of structure evaluation. Specifically, in the structure evaluation system 100, impact is applied by the impact application unit 15 to areas of the road surface where impact cannot be applied by the running part W of the vehicle 10. For example, in the structure evaluation system 100 in the first embodiment, impact is applied by the wheels W1 of the towed vehicle, which are positioned so as not to overlap with the running part W of the vehicle 10 in the vehicle width direction. This makes it possible to apply impact to areas of the road surface where impact cannot be applied by the running part W of the vehicle 10. Therefore, the dashed line WL can pass through areas that the dashed line WL would not pass through if impact were applied by the running part W of the vehicle 10, and thus the deterioration state can be evaluated even in areas where the deterioration state cannot be evaluated. As a result, it becomes possible to improve the accuracy of structure evaluation.

[0067] Patent Document 2 describes a system in which a device for generating elastic waves is provided on the front wheel side, and a receiving device is provided on the rear wheel side to inspect the soundness of concrete. In Patent Document 2, it is sufficient to generate elastic waves and receive them with the receiving device. Therefore, unlike the embodiment described above, the system is not configured to take into account the propagation path of the elastic waves and to apply impact to a second region of the structure 50 that is different from the first region of the structure that is impacted by the vehicle 10 running on the structure 50. As a result, in Patent Document 2, as described in the problem, the propagation path of the elastic waves passing through the inside of the structure was biased, and it was sometimes not possible to correctly evaluate internal damage. In contrast, in the embodiment described above, when an impact is applied by the vehicle 10 running on the vehicle W, the wavy line WL can pass through regions that the wavy line WL does not pass through, so the deterioration state can be evaluated even in regions where the deterioration state cannot be evaluated. Therefore, it becomes possible to improve the evaluation accuracy of the structure.

[0068] Patent Document 3 describes a system in which a vehicle is driven to measure friction on the pavement surface. Patent Document 1 describes a system in which tires arranged in the width direction of the vehicle are towed and driven to apply impact to the road surface. However, in this case, the elastic sources are lined up, which leads to interference between elastic waves and complicates the situation. In contrast, in the above-described embodiment, the wheels W1 of the impact application unit 15 are arranged offset in the direction of vehicle travel. This makes it less likely for interference between elastic waves to occur, and makes it possible to easily analyze the elastic waves.

[0069] A modified example of the first embodiment will now be described. In the embodiment described above, the wheel W1 of the towed vehicle, which serves as the impact-applying part 15, is positioned between the running parts W (tread) of the vehicle 10. The wheel W1 of the towed vehicle, which serves as the impact-applying part 15, may also be configured to be positioned outside the running parts W of the vehicle 10. The evaluation area of ​​the structural evaluation system 100 is the area formed by the arrangement of multiple sensors 20. Therefore, as long as the wheel W1 of the towed vehicle is within the evaluation area of ​​the structural evaluation system 100, its position outside the running parts W of the vehicle 10 will not affect the evaluation.

[0070] (Second embodiment) In the second embodiment, a configuration is described in which a water-spraying impact application unit is used as a method for generating elastic waves to deliver a denser impact. In the second embodiment, the system configuration of the structural evaluation system 100 itself is the same as in the first embodiment. The difference between the second embodiment and the first embodiment lies in the configuration of the impact application unit. The following will focus on the differences from the first embodiment.

[0071] Figure 10 is a diagram illustrating the method of generating elastic waves in the second embodiment. As shown in Figure 10, in the second embodiment, the impact-applying unit 15a is used to apply impact to the road surface by spraying water using a water-spraying vehicle or a water-spraying device such as a sprinkler. The water-spraying vehicle is a vehicle capable of traveling on the road surface while spraying water. For example, the water-spraying vehicle is a vehicle attached to the rear of vehicle 10. The watering by the water-spraying device is controlled so that the watering is applied to areas of the road surface that cannot be impacted by the wheels W1 of vehicle 10. The control of watering by the water-spraying device may be controlled by a control device provided in the water-spraying device. Control of watering by the water-spraying device includes the watering location and the timing of watering. The water-spraying device applies impact to the road surface by, for example, intermittently spraying water or by making the watering trajectory meander. In this case, the impact applied to the road surface is water droplets.

[0072] With this configuration, elastic waves caused by water droplets impacting the road surface due to watering propagate through the inside of the structure 50 and are detected by the sensor S. Since the elastic waves caused by water droplets impacting the road surface due to watering propagate along a different path than the elastic waves caused by the vehicle's running section W, it can be seen that a new path is added by the dashed line WL.

[0073] Figure 11 shows the location of additional elastic wave sources when water is sprayed intermittently by a watering device. Region A1 indicates the region where elastic wave sources are generated by the impact applied by the vehicle's running gear W. Region A3 indicates the region where elastic wave sources are generated by the impact applied by water spraying by the watering device. This configuration allows for the supplementation of regions where impact cannot be applied by the conventional vehicle's running gear W alone.

[0074] In particular, by intermittently spraying water, interference between elastic waves can be prevented, as in the first embodiment, and an impact suitable for elastic wave analysis can be applied. In the example shown in Figure 11, three water spraying points are provided between the running parts W, and the timing of water spraying is staggered at the center and both ends. When the water spraying points are fixed in this way, the elastic wave source position can be determined relative to the vehicle's running position. Therefore, verification of the elastic wave position determination results becomes easier. Alternatively, three water spraying points may be provided between the running parts W, and the timing of water spraying may be staggered at each point.

[0075] Figure 12 shows the locations of additional elastic wave sources when water is continuously sprayed by a watering device. Region A1 indicates the generation area of ​​elastic wave sources generated by the impact applied by the vehicle's running gear W. Region A3 indicates the generation area of ​​elastic wave sources generated by the impact applied by water spraying by the watering device. In the example shown in Figure 12, the trajectory of the water spray is made to meander. In this case, elastic wave sources can be generated over a wide area from a single watering point. By adopting this configuration, it is possible to complement areas that cannot be impacted by the conventional vehicle's running gear W alone.

[0076] The configurations shown in Figures 11 and 12 assume water is sprayed inside the tread of the vehicle 10, but the water spraying range may be extended to include the area outside the tread. Figure 13 shows the position of the additional elastic wave source when water is sprayed intermittently by the water spraying device, including the area outside the tread. Figure 14 shows the position of the additional elastic wave source when water is sprayed continuously by the water spraying device, including the area outside the tread. By performing watering as shown in Figures 13 and 14, the watering area can be expanded, thereby increasing the area that can be evaluated.

[0077] The structural evaluation system 100 in the second embodiment, configured as described above, makes it possible to improve the accuracy of structural evaluation, similar to the first embodiment. Specifically, in the structural evaluation system 100 in the second embodiment, impact is applied by watering a watering device to areas of the road surface where impact cannot be applied by the running section W of the vehicle 10. Therefore, the dashed line WL can be made to pass through areas where it would not pass if impact were applied by the running section W of the vehicle 10, making it possible to evaluate the deterioration state even in areas where the deterioration state could not be evaluated. As a result, it becomes possible to improve the accuracy of structural evaluation.

[0078] (Third embodiment) In the third embodiment, a configuration is described in which an impact-applying unit is used as a method for generating elastic waves to deliver a denser impact. In the third embodiment, the system configuration of the structural evaluation system 100 itself is the same as in the first embodiment. The difference between the third embodiment and the first embodiment lies in the configuration of the impact-applying unit. The following will focus on the differences from the first embodiment.

[0079] In the second embodiment, the impact-applying unit 15b is configured to apply an impact to the road surface by driving a vehicle equipped with an impact mechanism. For example, the vehicle equipped with the impact mechanism is a vehicle attached to the rear of the vehicle 10. The impact mechanism is, for example, a toothed rotating mechanism. The vehicle equipped with the impact mechanism is provided with one or more impact mechanisms. When the vehicle 10 is driven, the toothed rotating mechanism contacts the road surface at regular intervals, thereby applying an impact to the road surface. The impact mechanism is arranged so as not to overlap with the driving portion W of the vehicle 10 in the vehicle width direction, similar to the wheels W1 of the towed vehicle in the first embodiment.

[0080] Furthermore, the impact mechanism is not limited to a toothed rotating mechanism; any mechanism that can apply impact to the road surface is acceptable. For example, the impact mechanism may be one that strikes the road surface with a hammer or mallet at a timing controlled by a control device.

[0081] The structural evaluation system 100 in the third embodiment, configured as described above, makes it possible to improve the accuracy of structural evaluation, similar to the first embodiment. Specifically, in the structural evaluation system 100 in the third embodiment, an impact is applied to areas of the road surface where impact cannot be applied by the running section W of the vehicle 10, by a striking mechanism towed by the vehicle 10. Therefore, the dashed line WL can be made to pass through areas where it would not pass if an impact were applied by the running section W of the vehicle 10, making it possible to evaluate the deterioration state even in areas where the deterioration state could not be evaluated. As a result, it becomes possible to improve the accuracy of structural evaluation.

[0082] A modified example of the third embodiment will now be described. In the embodiment described above, the impact mechanism, which serves as the impact-applying part 15b, is shown to be positioned between the running parts W (tread) of the vehicle 10. The impact mechanism, which serves as the impact-applying part 15b, may also be configured to be positioned outside the running parts W of the vehicle 10.

[0083] (Fourth embodiment) In the fourth embodiment, a configuration is described in which a laser irradiation shock-applying unit is used as a method for generating elastic waves to deliver a denser impact. In the fourth embodiment, the system configuration of the structural evaluation system 100 itself is the same as in the first embodiment. The difference between the fourth embodiment and the first embodiment lies in the configuration of the shock-applying unit. The following description will focus on the differences from the first embodiment.

[0084] In the fourth embodiment, an irradiation device that emits a laser is provided as the impact-applying unit 15c on at least one of the vehicle 10 or the vehicle towed by the vehicle 10, and an impact is applied to the road surface by irradiating it with a laser when the vehicle 10 is driven. The irradiation device heats the road surface by irradiating it with a laser. An impact is applied to the road surface as it is heated by the laser irradiation. One or more irradiation devices are provided on at least one of the vehicle 10 or the vehicle towed by the vehicle 10. The irradiation device emits a laser at timings controlled by the control device. The laser irradiation by the irradiation device may be performed intermittently or continuously so that the laser trajectory meanders. If multiple irradiation devices are provided, the irradiation devices are arranged so as not to overlap with the running part W of the vehicle 10 in the vehicle width direction, similar to the wheels W1 of the towed vehicle in the first embodiment.

[0085] The structural evaluation system 100 in the fourth embodiment, configured as described above, makes it possible to improve the accuracy of structural evaluation, similar to the first embodiment. Specifically, in the structural evaluation system 100 in the fourth embodiment, impact is applied by laser irradiation from the irradiation device to areas of the road surface where impact cannot be applied by the running section W of the vehicle 10. Therefore, the dashed line WL can be made to pass through areas where it would not pass if impact were applied by the running section W of the vehicle 10, making it possible to evaluate the deterioration state even in areas where the deterioration state cannot be evaluated. As a result, it becomes possible to improve the accuracy of structural evaluation.

[0086] A modified example of the fourth embodiment will be described. In the embodiment described above, the irradiation device, which serves as the impact-applying unit 15c, is shown to be positioned between the running parts W (tread) of the vehicle 10. The irradiation device, which serves as the impact-applying unit 15c, may be positioned outside the running parts W of the vehicle 10 or configured to emit laser light.

[0087] The following describes modifications of the first to fourth embodiments. The signal processing unit 30 may be provided in the structural evaluation device 40.

[0088] In each of the embodiments described above, a configuration was shown in which multiple sensors 20-1 to 20-n are connected to a single signal processing unit 30. The structural evaluation system 100 may have multiple signal processing units 30, and each sensor 20 may be connected to a different signal processing unit 30.

[0089] Some of the functional units of the structural evaluation device 40 may be provided in other devices. For example, the display unit 44 of the structural evaluation device 40 may be provided in other devices. In this configuration, the structural evaluation device 40 transmits the evaluation results to the other device equipped with the display unit 44. The other device equipped with the display unit 44 displays the received evaluation results.

[0090] According to at least one embodiment described above, the accuracy of evaluating a structure can be improved by having an impact application unit 15 that applies impact to a second region of the structure different from the first region of the structure to which the running part W of a vehicle traveling on the structure has been impacted, a plurality of sensors 20 that detect elastic waves generated in the structure, a position determination unit 423 that determines the position of the source of the elastic waves based on the elastic waves detected by each of the plurality of sensors 20, and an evaluation unit 425 that evaluates the deterioration state of the structure based on the position determination result by the position determination unit 423.

[0091] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0092] 15, 15a, 15b, 15c…Impact application unit, 20, 20-1~20-n…Sensor, 30…Signal processing unit, 40…Structural evaluation device, 41…Communication unit, 42…Control unit, 43…Storage unit, 44…Display unit, 421…Acquisition unit, 422…Event extraction unit, 423…Position determination unit, 424…Distribution generation unit, 425…Evaluation unit, 301…Waveform shaping filter, 302…Gate generation circuit, 303…Arrival time determination unit, 304…Feature extraction unit, 305…Transmission data generation unit, 306…Memory, 307…Output unit

Claims

1. An impact-applying unit is mounted on the rear of a vehicle traveling on a structure and applies impact to a second region of the structure that does not overlap with the first region of the structure that was impacted by the vehicle's running section. Multiple sensors for detecting elastic waves generated in the first region of the structure that was impacted by the vehicle's running section and in the second region of the structure that was impacted by the impact application unit, A positioning unit that determines the position of the source of the elastic wave based on the elastic wave detected by each of the plurality of sensors, An evaluation unit evaluates the deterioration state of the structure for both the first and second regions based on the position determination results obtained by the position determination unit, Equipped with, The impact-applying unit is a watering device that sprays water, and the watering device applies an impact to the second region by spraying water. The range of watering by the watering device is wider than the distance between the running parts of the vehicle. Structural evaluation system.

2. The sprinkler system applies an impact to the second region by intermittently sprinkling water or by sprinkling water in a meandering trajectory. The structural evaluation system according to claim 1.

3. An impact-applying unit that applies impact to a second region of the structure that does not overlap with the first region of the structure that was impacted by the running part of a vehicle traveling on the structure, Multiple sensors for detecting elastic waves generated in the first region of the structure that was impacted by the vehicle's running section and in the second region of the structure that was impacted by the impact application unit, A positioning unit that determines the position of the source of the elastic wave based on the elastic wave detected by each of the plurality of sensors, An evaluation unit evaluates the deterioration state of the structure for both the first and second regions based on the position determination results obtained by the position determination unit, Equipped with, The impact application unit is an irradiation device that applies an impact to the structure by irradiating it with a laser, and the irradiation device heats the structure by irradiating it with the laser, thereby applying an impact to the second region. The irradiation range of the laser by the irradiation device is wider than the distance between the running parts of the vehicle. Structural evaluation system.

4. The impact-applying unit applies impact to the second region, which is the position between the running parts of the vehicle or to an area outside the running parts of the vehicle. A structural evaluation system according to any one of claims 1 to 3.

5. The irradiation device is positioned outside the running section of the vehicle. The structural evaluation system according to claim 3.

6. An impact-applying unit, mounted at the rear of a vehicle traveling on a structure, applies impact to a second region of the structure that does not overlap with the first region of the structure that was impacted by the vehicle's running section. The vehicle's running section detects the elastic waves generated in the first region of the structure that was impacted, and the impact-applying section detects the elastic waves generated in the second region of the structure that was impacted, Based on the detected elastic wave, the location of the source of the elastic wave is determined. Based on the results of the position determination, the deterioration state of the structure is evaluated for both the first and second regions. The impact-applying unit is a watering device that sprays water, and the watering device applies an impact to the second region by spraying water. The range of watering by the watering device is wider than the distance between the running parts of the vehicle. Structural evaluation methods.

7. The impact-applying unit applies impact to a second region of the structure that does not overlap with the first region of the structure that was impacted by the running part of a vehicle traveling on the structure. The vehicle's running section detects the elastic waves generated in the first region of the structure that was impacted, and the impact-applying section detects the elastic waves generated in the second region of the structure that was impacted, Based on the detected elastic wave, the location of the source of the elastic wave is determined. Based on the results of the position determination, the deterioration state of the structure is evaluated for both the first and second regions. The device that applies the impact is an irradiation device that applies an impact to the structure by irradiating it with a laser, and the irradiation device applies an impact to the second region by heating the structure with the irradiation of the laser. The irradiation range of the laser is wider than the distance between the running parts of the vehicle. Structural evaluation methods.

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