Damage evaluation device and damage evaluation program

Abstract

To provide a damage evaluation device capable of suppressing deterioration of evaluation accuracy due to environmental vibration.SOLUTION: A vibration unit 2 irradiates a structure 6 with a vibration excitation laser to vibrate a surface S1 of the structure 6. A measurement unit 3 irradiates a receiving point P2 of the structure 6 with a measurement laser, and measures the vibration using the reflected measurement laser. A damage evaluation unit 12 calculates damping data based on time series data of vibration data obtained by measurement, and determines damage to the structure 6 (healthy, damaged, various damage levels) based on the calculated damping data. More specifically, a Y-axis area is calculated based on the damping data. Next, a first map M1 is referred to determine which of a plurality of numerical ranges the calculated Y-axis area belongs to, and a degree of damage to the structure 6 associated with the determined numerical range to which the Y-axis area belongs is defined as an evaluation result of the damage to the structure 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a damage assessment device and a damage assessment program. [Background technology]

[0002] Conventionally, for example, a damage assessment device has been proposed that irradiates a structure with a laser to generate vibrations on the surface of the structure, measures the generated vibrations to obtain vibration data, and evaluates the soundness / damage of the structure based on the time series data of the obtained vibration data (see, for example, Patent Document 1). The damage assessment device described in Patent Document 1 is configured to perform a Fourier transform on the time series data of the vibration data to obtain a frequency spectrum, and evaluate the soundness / damage of the portion of the structure irradiated with the laser based on the obtained frequency spectrum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7129067 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the damage assessment device described in Patent Document 1, for example, when environmental vibrations are transmitted to the structure, the frequency spectrum changes, and there is a possibility that the assessment accuracy decreases. The present invention aims to provide a damage assessment device and a damage assessment program that can suppress a decrease in assessment accuracy due to environmental vibrations. [Means for solving the problem]

[0005] One aspect of the damage assessment device of the present invention is characterized by comprising: (a) a vibration data acquisition unit that acquires vibration data obtained by measuring vibrations generated in a structure; (b) a first data calculation unit that calculates, based on time series data of the acquired vibration data, first data for each elapsed time from the start of the specified period during a specified period of vibration measurement, by dividing the sum of squares of the amplitude of the vibration data from the start of the specified period by the sum of squares of the amplitude of the vibration data from the start of the specified period; and (c) a damage assessment unit that evaluates damage to the structure based on the calculated first data.

[0006] Furthermore, one aspect of the damage assessment program of the present invention is characterized in that it causes a computer to function as: (a) a vibration data acquisition unit that acquires vibration data obtained by measuring vibrations generated in a structure; (b) a first data calculation unit that calculates, based on the time series data of the acquired vibration data, first data for each elapsed time from the start of the specified period during a specified period of vibration measurement, by dividing the sum of squares of the amplitude of the vibration data from the start of the specified period by the sum of squares of the amplitude of the vibration data from the start of the specified period; and (c) a damage assessment unit that evaluates damage to the structure based on the calculated first data. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an overall configuration of a damage assessment device according to a first embodiment. [Diagram 2] FIG. 4 is a diagram showing the contents of a first map. [Diagram 3] FIG. 13 is a flowchart showing a damage determination process. [Figure 4] FIG. 13 is a diagram showing a vibration graph when the excitation point is a healthy part. [Diagram 5] FIG. 13 is a graph showing a vibration when the excitation point is a damaged area. [Figure 6] FIG. 13 is a diagram showing a damping graph when the excitation point is a healthy part. [Figure 7] FIG. 13 is a graph showing attenuation when the excitation point is a damaged area. [Figure 8]FIG. 13 is a diagram showing a frequency spectrum when the excitation point is a healthy part. [Figure 9] FIG. 13 is a diagram showing a frequency spectrum when the excitation point is a damaged area. [Figure 10] FIG. 2 is a diagram showing the overall configuration of a test specimen. [Figure 11] FIG. 13 is a diagram showing the relationship between the Y-axis area and the degree of damage. [Figure 12] FIG. 13 is a graph showing a correlation between the Y-axis area and the FFT integral value. [Figure 13] FIG. 4 is a diagram showing the overall configuration of a damage assessment device according to a second embodiment. [Figure 14] FIG. 13 is a diagram showing the contents of a second map. [Figure 15] FIG. 13 is a flowchart showing a damage determination process. [Figure 16] FIG. 13 is a diagram showing the relationship between ATT(tTH) and the degree of damage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An example of a damage assessment device according to an embodiment of the present invention will be described below with reference to Figs. 1 to 16. The embodiment of the present invention will be described in the following order. Note that the present invention is not limited to the following example. Also, the effects described in this specification are merely examples and are not limiting, and other effects may be present. 1. First embodiment 1-1 Overall configuration of the damage assessment device 1-2 Damage assessment process 1-3 Example 2. Second embodiment 2-1 Main components 2-2 Variations

[0009] 1. First embodiment [1-1 Overall configuration of the damage assessment device] The configuration of a damage assessment device 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of the damage assessment device 1. The damage assessment device 1 shown in FIG. 1 is a device that is mounted on a vehicle or the like, generates vibrations in a structure such as a tunnel, measures the generated vibrations, and evaluates damage to the structure based on the vibration data obtained by measuring the vibrations. Examples of the structure include concrete structures such as buildings, tunnels, and bridges, and mortar, tiles, and asphalt pavement on the surface of the concrete structure. Examples of damage include lifting, peeling, and internal cracks in concrete, mortar, tiles, asphalt, and the like. As shown in FIG. 1, the damage assessment device 1 includes a vibration unit 2, a measurement unit 3, a display unit 4, and a main body unit 5.

[0010] The vibration unit 2 is a device that applies an impact to the surface S1 of the structure 6 based on a signal from the main body 5. The vibration unit 2 includes a vibration laser oscillator and a laser scanning optical system. The vibration laser oscillator and the laser scanning optical system sequentially irradiate a vibration excitation laser to each of a plurality of vibration points P1 that are predetermined on the surface S1 of the structure 6, and generate ablation (explosive peeling) on ​​the surface S1 of the structure 6 to apply an impact. By applying such an impact, vibration is generated on the surface S1 of the structure 6. After irradiating the previous vibration point P1 with the vibration excitation laser, the next vibration point P1 is irradiated with the vibration excitation laser after waiting for a time for the vibration of the surface S1 caused by the vibration excitation laser to converge. For example, the irradiation is performed at intervals of 10 ms.

[0011] The measuring unit 3 is a device that measures vibrations of the surface S1 of the structure 6. The measuring unit 3 includes a laser Doppler vibrometer and a laser scanning optical system. The laser Doppler vibrometer and the laser scanning optical system irradiate a measurement laser to a vibration receiving point P2 on the surface S1 of the structure 6 at a predetermined sampling interval Δt, detect a change in the frequency of the reflected measurement laser (i.e., the Doppler-shifted measurement laser), and measure the vibrations of the surface S1 of the structure 6. The vibration measurement results (hereinafter also referred to as "vibration data") are output to the main body 5 at sampling intervals Δt. In addition, the vibration receiving point P2 is switched in accordance with the switching of the excitation point P1. The vibration receiving point P2 is set, for example, at a position 10 mm to 50 mm away from the excitation point P1. The display unit 4 is a device for presenting to an operator the results of the evaluation of damage to the structure 6 performed by the main body unit 5 based on a signal from the main body unit 5. As the display unit 4, for example, an indicator lamp such as an LED, or an image display device such as a liquid crystal display can be used.

[0012] The main body 5 is a computer, and includes a storage unit 7 and a control unit 8. The storage unit 7 stores a program for realizing each component of the main body unit 5, variables used when executing the program, and various types of information. As various types of information, for example, as shown in FIG. 2, there is a first map M1 that associates the damage degree of the structure 6 with each of a plurality of numerical ranges S0 to S1, S1 to S2, S2 to S3, S3 to S4, and S4 to S5. The magnitude relationship of S0 to S5 is in the order of S0 < S1 < S2 < S3 < S4 < S5. Each of the plurality of numerical ranges S0 to S1... S4 to S5 is a numerical range obtained by dividing the numerical range that the Y-axis area S described later can take. In the first map M1, "sound" is associated with the numerical range So to S1 as the damage degree of the structure 6. Also, "damage" is associated with the other numerical ranges S1 to S2,..., S4 to S5 as the damage degree of the structure 6. Further, "small damage level" is associated with the numerical range S1 to S2, "medium damage level" is associated with the numerical range S2 to S3, "large damage level" is associated with the numerical range S3 to S4, and "extremely large damage level" is associated with the numerical range S4 to S5. The magnitude relationship of the damage degrees from small damage level to extremely large damage level is in the order of small damage level < medium damage level < large damage level < extremely large damage level. The storage unit 7 is realized by a storage device such as a hard disk or a flash memory, for example.

[0013] The control unit 8 functions as a vibration control unit 9, a vibration data acquisition unit 10, a damping data calculation unit 11 (also referred to as a "first data calculation unit" in a broad sense), a damage evaluation unit 12, and a display control unit 13 when a processing unit such as a CPU or a GPU included in the main body unit 5 executes a program stored in the storage unit 7 (a program for damage determination processing described later (also referred to as a "program for damage evaluation" in a broad sense)). Further, the damage evaluation unit 12 includes a Y-axis area calculation unit 14 (also referred to as a "second data calculation unit" in a broad sense) and an evaluation execution unit 15.

[0014] [1-2 Damage determination processing] Next, the damage determination processing executed by the control unit 8 will be described. The damage assessment process realizes the above-mentioned functions 9 to 15, and evaluates the damage of the excitation point P1 of the structure 6 by these functions 9 to 15, and presents the evaluation result to the operator. Moreover, when the damage assessment process is started, it is repeatedly executed by switching the excitation point P1 in order. In the damage assessment process, as shown in Fig. 3, first, in step S101, the vibration control unit 9 outputs a signal for emitting a vibration excitation laser (hereinafter also referred to as "vibration signal") to the vibration unit 2. By outputting such a vibration signal, the vibration unit 2 irradiates the vibration excitation laser to the vibration point P1 on the surface S1 of the structure 6, generating ablation on the surface S1 of the structure 6 and applying an impact. Then, by applying such an impact, vibration is generated on the surface S1 of the structure 6. In addition, the vibration control unit 9 causes the measurement unit 3 to start measuring the vibration of the surface S1 of the structure 6.

[0015] Next, the process proceeds to step S102, where the vibration data acquisition unit 10 acquires the vibration data output from the measurement unit 3 (i.e., the vibration data wave(i) (i=0, 1 to n) obtained by measuring the vibration generated in the structure 6). The vibration data wave(i) is acquired, for example, repeatedly at sampling intervals Δt for a predetermined time (e.g., 3 ms to 5 ms) after an impact is applied to the structure 6. By repeating the acquisition of the vibration data wave(i) in this manner, time-series data of the vibration data wave(i) is acquired, as shown in Figs. 4 and 5. Figs. 4 and 5 are diagrams showing graphs (hereinafter also referred to as "vibration graphs") obtained by plotting the vibration data wave(i) at every sampling interval Δt, with the horizontal axis representing time and the vertical axis representing the vibration data wave(i). Fig. 4 is a vibration graph when the excitation point P1 is a healthy part, and Fig. 5 is a vibration graph when the excitation point P1 is a damaged part. As shown in Figs. 4 and 5, when the vibration point P1 is a damaged part, it takes a longer time for the vibration to subside than when it is a healthy part.

[0016] Next, the process proceeds to step S103, where the attenuation data calculation unit 11 calculates normalized waveform energy data ATT(t) (hereinafter also referred to as "attenuation data" or, in a broader sense, as "first data") according to the following formula (1) based on the time series data of the vibration data wave(i) acquired in step S102 and the sampling interval Δt. In the following formula (1), based on the time series data of the acquired vibration data wave(i), for each elapsed time t from the start time to of the predetermined period to to te within the measurement period of the vibration by the measurement unit 3, the sum of squares of the amplitude of the vibration data wave(i) from the start time to to the elapsed time t is divided by the sum of squares of the amplitude of the vibration data wave(i) from the start time to to the end time te of the predetermined period to to te to calculate the attenuation data ATT(t). By calculating the attenuation data ATT(t) for each elapsed time t in this way, the time series data of the attenuation data ATT(t) is acquired as shown in FIG. 6 and FIG. 7. 6 and 7 are diagrams showing normalized waveform energy integrated value curves (hereinafter also referred to as "attenuation graphs") obtained by plotting attenuation data ATT(t) at sampling intervals Δt, with the horizontal axis being elapsed time t and the vertical axis being attenuation data ATT(t). FIG. 6 is an attenuation graph when the excitation point P1 is a healthy part, and FIG. 7 is an attenuation graph when the excitation point P1 is a damaged part. In FIG. 6 and FIG. 7, the predetermined period to to te is exemplified by setting the time when vibration occurs as the start time to and the time when vibration sufficiently converges (for example, the time when 5 ms has elapsed from the start time to) as the end time te during the period of vibration measurement by the measurement unit 3.

number

[0017] In this way, the attenuation data ATT(t) is calculated using the above formula (1). That is, the area of ​​vibration (=Σwave(i) 2) is used. Therefore, as shown in Figs. 6 and 7, the attenuation graph is a graph that emphasizes the time-dependent characteristics such as the amplitude envelope 16 and period of the vibration graphs shown in Figs. 4 and 5. Therefore, the attenuation graph (attenuation data ATT(t)) is calculated by using the attenuation data ATT(t) when the elapsed time t is from the start time to to the switching time t TH (broadly referred to as a "predetermined time"), the increase rate α of the attenuation data ATT(t) relative to the increase in the elapsed time t is maintained at a predetermined constant value αo, and the elapsed time t is equal to or greater than the switching time t TH Within the range below, the increase rate α has a characteristic of being lower than the constant value αo.

[0018] Next, the process proceeds to step S104, where the Y-axis area calculation unit 14 calculates the Y-axis area S (also referred to as "second data" in a broad sense) based on the time series data of the attenuation data ATT(t) acquired in step S103 according to the following formula (2). In the following formula (2), as shown in Figs. 6 and 7, the attenuation data ATT(t) (=ATT(Δt·i)) is subtracted from "1" for each elapsed time t, and the Y-axis area S is calculated as the sum of the subtraction results (1-ATT(Δt·i)) for each elapsed time t. The Y-axis area S is the area of ​​the halftone dots shown in Figs. 6 and 7. That is, the Y-axis area calculation unit 14 expresses the area surrounded by the normalized waveform energy integrated value curve as the area on the opposite side (complementary area), and performs processing to obtain the normalized waveform energy integrated value area (Y-axis area S), in which the difference in change is easily reflected in the numerical value, as the evaluation value of damage.

number

[0019] Here, as shown in FIG. 4 and FIG. 5, when the excitation point P1 is a damaged part, it takes more time for the vibration to subside than when it is a healthy part. Therefore, as shown in FIG. 6 and FIG. 7, in the attenuation graph, the value of the attenuation data ATT(t) at each elapsed time t becomes small, and the value of the Y-axis area S becomes large. Therefore, the Y-axis area S changes in size when the excitation point P1 is a healthy part and when it is a damaged part, and also changes in size depending on the progress of the damage (hereinafter, also referred to as the "degree of damage"). That is, when the excitation point P1 is a healthy part, the value of the Y-axis area S becomes smallest, and when it is a damaged part, the value becomes larger as the progress of the damage worsens (as the degree of damage increases). Therefore, in the first embodiment, the damage of the structure 6 is evaluated using the Y-axis area S. Note that the Y-axis area S, that is, the sum of (1-ATT(Δt·i)) (the area of ​​the dotted parts in Figures 6 and 7), has significantly different possible values ​​for healthy and damaged parts than the sum of ATT(Δt·i) (the area opposite the dotted parts above), and these differences are more likely to be reflected in the numerical value. Therefore, the accuracy of the evaluation can be improved by using the Y-axis area S.

[0020] Next, the process proceeds to step S105, where the evaluation execution unit 15 refers to the first map M1 (see FIG. 2) stored in the storage unit 7 and determines which of the multiple numerical ranges S0-S1, S1-S2, S2-S3, S3-S4, or S4-S5 the Y-axis area S calculated in step S104 belongs to. Then, the damage degree of the structure 6 associated with the numerical range that it is determined to belong to is taken as the evaluation result of the damage of the structure 6. For example, when it is determined that the Y-axis area S belongs to the numerical range S0-S1, it is determined that the excitation point P1 of the structure 6 is a healthy part (healthy). Similarly, when it is determined that the Y-axis area S belongs to the numerical range S1-S2, it is determined that the excitation point P1 of the structure 6 is a damaged part (damage) and the damage degree is "low damage level". Also, when it is determined that the value falls within the numerical range S2 to S3, it is determined that the excitation point P1 of the structure 6 is a damaged part (damage) and the damage degree is "medium damage level". When it is determined that the value falls within the numerical range S3 to S4, it is determined that the excitation point P1 of the structure 6 is a damaged part (damage) and the damage degree is "high damage level". When it is determined that the value falls within the numerical range S4 to S5, it is determined that the excitation point P1 of the structure 6 is a damaged part (damage) and the damage degree is "extra high damage level". Through such operations of the Y-axis area calculation unit 14 and the evaluation execution unit 15, the damage evaluation unit 12 including the Y-axis area calculation unit 14 and the evaluation execution unit 15 evaluates the damage of the structure 6 based on the attenuation data ATT(t) calculated by the attenuation data calculation unit 11. Next, the process proceeds to step S106, where the display control unit 13 causes the display unit 4 to present the evaluation result of the damage to the structure 6 obtained in step S105, and then ends this damage determination process. By presenting the evaluation result in this manner, the operator is notified of the evaluation result.

[0021] In the damage evaluation device 1 having the above configuration, a vibration excitation laser is irradiated onto the vibration point P1 of the structure 6, the surface S1 of the structure 6 is vibrated, a measurement laser is irradiated onto the structure 6, and the vibration (vibration data wave(i)) is measured by the reflected measurement laser. Then, attenuation data ATT(t) is calculated based on the time series data of the vibration data wave(i) obtained by measurement, and damage (sound, damaged, various damage levels) of the structure 6 is judged based on the calculated attenuation data ATT(t). Specifically, the Y-axis area S is calculated according to the above formula (2) based on the attenuation data ATT(t). Next, the first map M1 is referred to, and it is judged which of a plurality of numerical ranges S0 to S1 ... S4 to S5 the calculated Y-axis area S belongs to, and the damage degree of the structure 6 associated with the numerical range that it is judged to belong to is set as the evaluation result of the damage of the structure 6. As a result, the damage of the structure 6 can be evaluated, and the evaluation result can be provided to the operator.

[0022] Here, for example, as Comparative Example 1, a case is considered in which damage to the structure 6 is evaluated using the integral value of the envelope 16 of the amplitude of the vibration graph shown in FIG. 4 and FIG. 5 (in other words, the area surrounded by the envelope 16). The integral value of the envelope 16 is the sum of the vibration data wave(i) from the start time to to the end time te. At this time, if the structure 6 is damaged, the integral value is larger than if there is no damage. Therefore, if the integral value is smaller than the threshold value, the vibration point P1 of the structure 6 is judged to be "sound", and if it is equal to or greater than the threshold value, it is judged to be "damaged". That is, in Comparative Example 1, it is possible to evaluate only "sound" and "damaged", that is, the presence or absence of damage. However, in Comparative Example 1, it is not possible to evaluate the progress of damage. In contrast, the damage assessment device 1 according to the first embodiment is configured to assess damage to the structure 6 using time series data of attenuation data ATT(t) for a predetermined period to to te. Here, the numerator of the attenuation data ATT(t) at each elapsed time t is the sum of the squared values ​​of the amplitude of the vibration data wave(i) from the start time to to the elapsed time t. Therefore, the numerator of the attenuation data ATT(te) at the end time te has a range from the start time to to the end time te, as in Comparative Example 1. Therefore, according to the configuration for assessing damage to the structure 6 using time series data of attenuation data ATT(t) for a predetermined period to to te, unlike a method of assessing damage using only attenuation data ATT(te) at the end time te, the sum of the squared values ​​of the amplitude of the vibration data wave(i) at each elapsed time t between to and te is also used for the assessment of damage. In other words, since the attenuation data ATT(t) from the process leading up to the attenuation data ATT(te) at the end point te can also be used, the attenuation process can also be taken into consideration for evaluation, and not only the presence or absence of damage (e.g., "healthy" or "damaged") but also the progression of the damage (degree of damage) can be evaluated.

[0023] Also, for example, as Comparative Example 2, a case where damage to the structure 6 is evaluated using an integral value of the spectrum power (hereinafter, also referred to as an "FFT integral value") is considered. Specifically, vibration data wave(i) obtained by measuring vibrations occurring in the structure 6 is acquired, and as shown in Figs. 8 and 9, the time series data of the acquired vibration data wave(i) is Fourier transformed to obtain a frequency spectrum, and the obtained frequency spectrum is normalized so that the maximum value of the spectrum power is "1" to calculate an integrated value of the spectrum power. Then, if the calculated integrated value is greater than a threshold value, the vibration point P1 of the structure 6 is judged to be "sound", and if it is equal to or less than the threshold value, it is judged to be "damaged". When damage is evaluated using this FFT integral value, for example, if environmental vibrations such as vibrations of the engine of a vehicle equipped with the damage evaluation device 1 are transmitted to the structure 6, the integrated value of the spectrum power may increase, and the evaluation accuracy of the damage to the structure 6 may decrease. Figs. 8 and 9 are diagrams showing frequency spectra showing the relationship between angular frequency and spectrum power. In addition, Fig. 8 shows the frequency spectrum when the excitation point P1 is a healthy part, and Fig. 9 shows the frequency spectrum when the excitation point P1 is a damaged part. The integrated value of the spectrum power is the area of ​​the dotted part shown in Figs. 8 and 9.

[0024] In contrast, the damage assessment device 1 according to the first embodiment is configured to assess damage to the structure 6 using the Y-axis area S, that is, the area of ​​the attenuation graph (see Figs. 6 and 7). Here, as described above, the attenuation graph is a graph that emphasizes the shape characteristics of the envelope 16 of the amplitude of the vibration graph shown in Figs. 4 and 5. Therefore, for example, even if environmental vibration is transmitted to the structure 6, the impact of the environmental vibration on the shape of the envelope 16 is small, so that the impact of the environmental vibration on the attenuation graph is small, and the impact of the Y-axis area S is small. Therefore, it is possible to suppress a decrease in the assessment accuracy of damage to the structure 6 caused by the environmental vibration. As will be described later, for example, when there is no environmental vibration, a method of evaluating damage to a structure 6 using the Y-axis area S (the evaluation method of the damage evaluation device 1 according to the first embodiment) can obtain evaluation accuracy equivalent to that of an evaluation method using an FFT integral value.

[0025] [1-3 Example] Next, an example of the damage assessment device 1 according to the first embodiment will be described. First, as shown in FIG. 10, a specimen was prepared in which a rebar 61 (outer diameter 13 mm, cover 30 mm) was embedded in a concrete specimen 62 (vertical direction 200 mm, horizontal direction 200 mm, depth direction 400 mm) as a structure 6 for checking damage. Then, as shown in FIG. 11(a), FIG. 11(b) and FIG. 11(c), damage was generated in the concrete specimen 62 under the conditions of an expansion area of ​​150 mm, expansion times of 1.25 days, 1.75 days and 6.25 days, and static crushing agent of 48 hours. FIG. 11(a) is a cut surface of the specimen with an expansion time of 1.25 days, FIG. 11(b) is a cut surface of the specimen with an expansion time of 1.75 days, and FIG. 11(c) is a cut surface of the specimen with an expansion time of 6.25 days. In FIG. 11(a), FIG. 11(b) and FIG. 11(c), the longer the expansion time, the greater the degree of damage to the concrete specimen 62.

[0026] Next, using the damage assessment device 1 according to the first embodiment, in a state in which there is no environmental vibration, the Y-axis area S was obtained along the upper and right sides of the planned position of the cut surface shown in Fig. 11(a) to Fig. 11(c) for each specimen, and a damping graph was created based on the obtained Y-axis area S. Next, the damping graph was arranged on the upper and right sides of the cut surface of the specimen to create Fig. 11(a) to Fig. 11(c). It was confirmed from Fig. 11(a) to Fig. 11(c) that the greater the degree of damage to the concrete test piece 62, the larger the value of the Y-axis area S. In addition, in the attenuation graph on the right side of the cut surface in Fig. 11(c), the Y-axis area S is reduced in the area where a large peeled block occurs near the reinforcing bar 61. This is because the vibration generated by the vibration excitation laser is smaller due to the large peeled block, and the vibration data wave(i) is smaller. The same evaluation result is obtained by the evaluation method using the above-mentioned FFT integral value.

[0027] In addition, the FFT integral value was calculated based on the vibration data wave(i) used to calculate the Y-axis area S. Then, as shown in FIG. 12, the horizontal axis is the Y-axis area S, the vertical axis is the FFT integral value, and the calculation results (Y-axis area S, FFT integral value) are plotted to create a correlation graph of the Y-axis area-FFT integral value. According to this correlation graph, it was confirmed that there is a good correlation in which the larger the FFT integral value, the smaller the Y-axis area S becomes, and the smaller the FFT integral value, the larger the Y-axis area S becomes. Therefore, it was also confirmed that the method of evaluating the damage of the structure 6 using the Y-axis area S (the evaluation method of the damage evaluation device 1 according to the first embodiment) has the same evaluation accuracy as the evaluation method using the FFT integral value when there is no environmental vibration.

[0028] 2. Second embodiment [2-1 Configuration of main parts] Next, a damage assessment device 1 according to a second embodiment of the present disclosure will be described. Fig. 13 is a diagram showing the overall configuration of the damage assessment device 1 according to the second embodiment. In Fig. 13, parts corresponding to those in Fig. 1 are given the same reference numerals, and duplicated explanations will be omitted.

[0029] The damage assessment device 1 according to the second embodiment is configured to detect the switching time t TH Attenuation data ATT(t TH ) to evaluate damage to the structure 6. In the second embodiment, as shown in Figs. 13 and 14, the memory unit 7 stores a second map M2 instead of the first map M1. The control unit 8 realizes an attenuation data extraction unit 17 (also called a "first data extraction unit" in a broad sense) instead of the Y-axis area calculation unit 14. As shown in Fig. 15, the damage assessment process has steps S201 and S202 instead of steps S104 and S105.

[0030] As shown in FIG. 14, the second map M2 is a map in which a plurality of numerical ranges ATT0-ATT1, ATT1-ATT2, ATT2-ATT3, ATT3-ATT4, and ATT4-ATT5 are associated with the damage level (low damage level, medium damage level, high damage level, and extra high damage level) of the structure 6. As shown in FIG. 6, FIG. 7, and FIG. 16, the magnitude relationship of ATT0-ATT5 is in the order of ATT0>ATT1>ATT2>ATT3>ATT4>ATT5. FIG. 6, FIG. 7, and FIG. 16 illustrate the case where ATT0=1.0, ATT1=0.8, ATT2=0.65, ATT3=0.55, ATT4=0.4, and ATT5=0.0. Each of the plurality of numerical ranges ATT0-ATT1...ATT4-ATT5 corresponds to the switching time t TH Attenuation data ATT(t TH In the second map M2, the numerical range ATTo to ATT1 is associated with "sound" as the damage level of the structure 6. In the second map M2, the other numerical ranges ATT1-ATT2, ..., ATT4-ATT5 are associated with "damage" as the degree of damage to the structure 6. In addition, the numerical range ATT1-ATT2 is associated with a "small damage level," the numerical range ATT2-ATT3 is associated with a "medium damage level," the numerical range ATT3-ATT4 is associated with a "large damage level," and the numerical range ATT4-ATT5 is associated with a "extra large damage level."

[0031] As shown in FIG. 15, in step S201 of the damage determination process, the attenuation data extraction unit 17 extracts at least one attenuation data ATT(t) calculated for each elapsed time t in step S103 from the attenuation data ATT(t). TH The attenuation data ATT(t TH As described above, the attenuation data ATT(t) is calculated by dividing the elapsed time t from the start time t to the switching time t TH When the elapsed time t is within the range of t to t, the increase rate α of the attenuation data ATT(t) relative to the increase in the elapsed time t is maintained at a predetermined constant value αo, and the elapsed time t is THWithin the range above this, the increase rate α has the characteristic of decreasing below the constant value αo (see FIG. 6 and FIG. 7). Therefore, the switching time t TH As a method of extracting the switching time t, for example, the elapsed time t is gradually increased from the start time t, the increase rate α is calculated for each elapsed time t, and the elapsed time t at which the increase rate α, which had been maintained at a constant value αo, falls below the constant value αo is defined as the switching time t. TH A method of extracting the above-mentioned

[0032] In step S202, the evaluation execution unit 15 refers to the second map M2 (see FIG. 14) stored in the storage unit 7, and calculates the attenuation data ATT(t TH It is determined to which of a plurality of numerical ranges ATT0-ATT1...ATT4-ATT5 the attenuation data ATT(t TH If it is determined that the attenuation data ATT(t TH ) is determined to be in the numerical range ATT1 to ATT2, the vibration point P1 of the structure 6 is determined to be a damaged part (damage) and the damage degree is "small damage level". If it is determined to be in the numerical range ATT2 to ATT3, the vibration point P1 of the structure 6 is determined to be a damaged part (damage) and the damage degree is "medium damage level". If it is determined to be in the numerical range ATT3 to ATT4, the vibration point P1 of the structure 6 is determined to be a damaged part (damage) and the damage degree is "large damage level". If it is determined to be in the numerical range ATT4 to ATT5, the vibration point P1 of the structure 6 is determined to be a damaged part (damage) and the damage degree is "extra large damage level".

[0033] In the damage assessment device 1 having the above configuration, a vibration excitation laser is irradiated onto the vibration point P1 of the structure 6, vibrating the surface S1 of the structure 6, a measurement laser is irradiated onto the structure 6, and the vibration (vibration data wave(i)) is measured by the reflected measurement laser. Then, damping data ATT(t) is calculated based on the time series data of the vibration data wave(i) obtained by measurement, and damage to the structure 6 is judged based on the calculated damping data ATT(t). Specifically, from the damping data ATT(t), a switching time t TH The attenuation data ATT(t TH ) is extracted. Next, the second map M2 is referenced to extract the attenuation data ATT(t TH ) belongs to any one of a plurality of numerical ranges ATT0-ATT1...ATT4-ATT5, and the degree of damage to the structure 6 associated with the numerical range to which it is determined that the structure 6 belongs is taken as the evaluation result of the damage to the structure 6. In this way, the damage to the structure 6 can be evaluated, and the evaluation result can be provided to the operator.

[0034] In the correlation graph of FIG. 12 created in the example of the first embodiment, "◇" indicates ATT(t TH ) is 0.9 (see Fig. 16(a)), and "○" indicates ATT(t TH ) is 0.7 (see Fig. 16(b)), and "△" indicates ATT(t TH ) is 0.6 (see Fig. 16(c)), and "□" indicates ATT(t TH ) is 0.5 (see Fig. 16(d)), and "×" indicates ATT(t TH ) is 0.3 (see FIG. 16(e)). Therefore, according to the correlation graph in FIG. 12, the FFT integral value and the attenuation data ATT(t TH ) the larger the FFT integral value, the greater the attenuation data ATT(t TH ) becomes smaller, and the smaller the FFT integral value, the greater the attenuation data ATT(t TH ) is large. Therefore, it can be confirmed that there is a good correlation between the attenuation data ATT(t TH According to the method of evaluating damage to the structure 6 using FFT integral values ​​(the evaluation method of the second embodiment), similarly to the method of evaluating damage to the structure 6 of the first embodiment, the evaluation accuracy is equivalent to that of the evaluation method using FFT integral values.

[0035] [2-2 Modified Example] (1) In the first and second embodiments, an example is shown in which the excitation unit 2 has a laser oscillator for excitation and the measurement unit 3 has a laser Doppler vibrometer to perform the laser hammering test, but other configurations can be adopted. For example, the excitation unit 2 may have a hammer and the measurement unit 3 has a microphone to perform the hammer hammering test. Here, as shown in the above formula (1), the attenuation data ATT(t) is divided by the sum of squares of the amplitude of the vibration data wave(i) from the start time to to the end time te, so that the magnitude is normalized. Therefore, in the evaluation method of the damage evaluation device 1 according to the first and second embodiments using the attenuation data ATT(t), the same threshold value (first map M1, second map M2) can be used whether the excitation unit 2 has a laser oscillator for excitation or a hammer.

[0036] (2) In the first and second embodiments, an example has been shown in which all of the vibration unit 2, the measurement unit 3, and the main body unit 5 are included in one device (damage assessment device 1), but other configurations may also be adopted. For example, a configuration may be adopted in which vibration data wave(i) is acquired by another device equipped with the vibration unit 2 and the measurement unit 3, and the damage assessment device 1 receives the vibration data wave(i) from the other device, and evaluates damage (soundness, damage, various damage levels) of the structure 6 based on the received vibration data wave(i). In this case, the damage assessment device 1 may be configured not to include the vibration unit 2 and the measurement unit 3. [Explanation of symbols]

[0037] Reference Signs List 1...Damage assessment device, 2...Vibration unit, 3...Measuring unit, 4...Display unit, 5...Main body, 6...Structure, 61...Reinforcing bar, 62...Concrete test piece, 7...Memory unit, 8...Control unit, 9...Vibration control unit, 10...Vibration data acquisition unit, 11...Damping data calculation unit, 12...Damage assessment unit, 13...Display control unit, 14...Y-axis area calculation unit, 15...Evaluation execution unit, 16...Envelope, 17...Damping data extraction unit

Claims

1. a vibration data acquisition unit that acquires vibration data obtained by measuring vibrations occurring in the structure; a first data calculation unit that calculates, for each elapsed time from a start point of a predetermined period within a vibration measurement period, first data by dividing a sum of squares of amplitudes of the vibration data from the start point to the elapsed time by a sum of squares of amplitudes of the vibration data from the start point to an end point of the predetermined period based on time-series data of the vibration data that has been acquired; a damage assessment unit that assesses damage to the structure based on the calculated first data. Damage assessment device.

2. a first map that associates a damage degree of the structure with each of a plurality of numerical ranges; The damage assessment unit includes: a second data calculation unit that calculates second data, the second data being a sum of respective subtraction results for each elapsed time, the second data being obtained by subtracting the first data from “1” for each elapsed time; and an evaluation execution unit that refers to the first map, determines which of the plurality of numerical ranges the second data belongs to, and sets the degree of damage to the structure associated with the numerical range to which the second data belongs as an evaluation result of the damage to the structure. The damage assessment device according to claim 1 .

3. a second map that associates a damage degree of the structure with each of a plurality of numerical ranges; the first data has a characteristic that, when the elapsed time is within a range from the start time to a predetermined time, an increase rate of the first data relative to an increase in the elapsed time is maintained at a predetermined constant value, and, when the elapsed time is within a range after the predetermined time, the increase rate decreases below the constant value; The damage assessment unit includes: a first data extraction unit that extracts the first data corresponding to the predetermined time from the first data calculated for each elapsed time; and an evaluation execution unit that refers to the second map, determines which of the plurality of numerical ranges the extracted first data belongs to, and sets the degree of damage to the structure that corresponds to the numerical range to which the extracted first data belongs as an evaluation result of damage to the structure. The damage assessment device according to claim 1 .

4. A vibration unit that generates vibrations on a surface of the structure; A measurement unit that measures vibrations of the surface, The vibration data acquisition unit acquires the vibration data output from the measurement unit. The damage assessment device according to claim 1 .

5. Computer, a vibration data acquisition unit that acquires vibration data obtained by measuring vibrations occurring in the structure; a first data calculation unit that calculates, for each elapsed time from a start point of a predetermined period within a vibration measurement period, first data by dividing a sum of squares of amplitudes of the vibration data from the start point to the elapsed time, by a sum of squares of amplitudes of the vibration data from the start point to an end point of the predetermined period, based on time-series data of the acquired vibration data; and for functioning as a damage assessment unit that assesses damage to the structure based on the calculated first data. A program for damage assessment.

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