JP2012237561A - Inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device which allows for efficient inspection over a wide range of structure surface in a short analysis time, and an inspection method using the same.SOLUTION: An inspection device comprises a strike oscillator 100 which strikes a predetermined position at a predetermined frequency, a first laser Doppler velocimeter 201 which detects physical quantities at a first position of an inspection surface, a second laser Doppler velocimeter 202 which detects physical quantities at a second position of the inspection surface, first filter means which selects a first physical quantity related to the amplitude of a surface wave from the physical quantities detected by the first laser Doppler velocimeter 201, second filter means which selects a second physical quantity related to the amplitude of a surface wave from the physical quantities detected by the second laser Doppler velocimeter 202, calculation means which calculates a ratio of the first physical quantity to the second physical quantity, and display means which displays the calculated ratio corresponding to the position struck by the strike oscillator 100.

Description

  The present invention relates to an inspection apparatus used for inspecting crack depth and position in a concrete structure.

  Reinforced concrete structures tend to cause fine cracks on the surface due to the properties of the concrete, but when these cracks progress and reach the rebar, the rebar will corrode, affecting the durability of the structure and the safety of the structure. Will be affected.

  In view of this, in reinforced concrete structures, visual observation and crack width investigation are conducted through periodic inspections for maintenance and soundness assessment after earthquakes. By the way, since such a survey is manual and requires labor and time, various inspection apparatuses for inspecting and grasping the internal situation of the reinforced concrete structure are proposed in order to perform this more efficiently. Has been.

For example, Patent Document 1 (Japanese Patent Laid-Open No. 2003-35703) discloses a damper disposed on a measurement surface of a concrete structure, and a vibration detector that converts vibration of the measurement surface into an electrical signal via the damper. A vibration component having a frequency of approximately 5 kilohertz or less included in the vibration is detected by the vibration detector via the damper, and the inside of the concrete structure is nondestructively inspected based on the detection output. A non-destructive inspection device for a concrete structure is disclosed.
JP 2003-35703 A

  In the inspection of concrete structures in conventional inspection equipment, a method of sensing the attenuation of longitudinal elastic waves is adopted. However, in such a method, the attenuation due to cracks in the concrete structure is large, and cracks are not generated. There is a problem that the application range is limited because it is necessary to perform measurement in the vicinity and a considerable time is required for measurement and analysis.

The present invention solves the above-mentioned problem, and the invention according to claim 1 is a striking vibrator that strikes a predetermined position on the inspection surface at a predetermined frequency, and the inspection at the first position of the inspection surface. A first laser Doppler velocimeter for detecting a physical quantity related to vibration of a surface; a second laser Doppler velocimeter for detecting a physical quantity related to vibration of the inspection surface at a second position of the inspection surface; and the first laser Doppler speed. The physical quantity relating to the vibration of the inspection surface detected by the meter is corrected in accordance with the distance between the impact position by the impact vibrator and the first position to obtain a first corrected physical quantity. The physical quantity related to the vibration of the inspection surface detected by the correction means and the second laser Doppler velocimeter is compensated according to the distance between the impact position by the impact vibrator and the second position. Second correction means for obtaining a second correction physical quantity, and first filter means for extracting a first physical quantity related to the magnitude of the surface wave from the first correction physical quantity obtained by the first correction means, Second filter means for extracting a second physical quantity related to the magnitude of the surface wave from the previous second corrected physical quantity detected by the second laser Doppler velocimeter, and a first physical quantity extracted by the first filter means Calculating means for calculating a ratio with the second physical quantity extracted by the second filter means; and displaying means for displaying the ratio calculated by the calculating means in correspondence with the impact position by the impact vibrator. And an inspection apparatus characterized by comprising:

  Further, the invention according to claim 2 is the inspection apparatus according to claim 1, wherein the crack depth is calculated from the first physical quantity extracted by the first filter means and the second physical quantity extracted by the second filter means. It has a crack depth specifying means for specifying the thickness.

  According to a third aspect of the present invention, in the inspection apparatus according to the first aspect, the crack position is calculated from the first physical quantity extracted by the first filter means and the second physical quantity extracted by the second filter means. It is characterized by having a crack position specifying means for specifying.

  The invention according to claim 4 is a striking vibrator that strikes a predetermined position on an inspection surface at a predetermined frequency, a plurality of laser Doppler velocimeters that detect a physical quantity related to vibration of the inspection surface, The physical quantity related to the vibration of the inspection surface detected by the laser Doppler velocimeter is corrected according to the distance between the impact position by the impact vibrator and the fixed position of each of the plurality of laser Doppler velocimeters. Correction means for obtaining a plurality of corrected physical quantities, a filter means for extracting a plurality of physical quantities related to the magnitude of a surface wave from the plurality of corrected physical quantities obtained by the correcting means, and a filter means extracted by the filter means A calculation means for calculating a ratio of two arbitrary physical quantities among the plurality of physical quantities, and a ratio calculated by the calculation means are calculated by the impact vibrator. Display means for displaying in correspondence with striking impact position, an inspection apparatus characterized by having a.

  According to the inspection apparatus according to the present invention, based on the ratio (or difference in the case of logarithmic display) of the physical quantity related to the magnitude of the surface wave, obtained from a plurality of laser Doppler velocimeters that measure a predetermined position in advance. It is possible to estimate information on cracks in the target area. According to the inspection apparatus of the present invention, it is not necessary to perform an inspection in the vicinity of a crack, and the time required for the analysis is short, and it is possible to efficiently inspect a wide range of structure surfaces. And according to such an inspection device concerning the present invention, a rational repair plan can be performed.

It is a figure showing typically the outline of inspection device 10 concerning the embodiment of the present invention. It is a figure which shows the outline of the flow of the data processing in the test | inspection apparatus 10 which concerns on embodiment of this invention. It is a figure which shows the example of data acquisition of the inspection object area | region for obtaining mapping. It is a figure which shows roughly the detection vibration waveform acquired and corrected with the 1st laser Doppler velocimeter and the 2nd laser Doppler velocimeter. It is a figure explaining the outline of the measurement principle of the inspection apparatus 10 which concerns on embodiment of this invention. It is a figure which shows the outline of the vertical distribution of a surface wave.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing an outline of an inspection apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a concrete structure, 10 is an inspection device, 100 is an impact vibrator, 201 is a first laser Doppler velocimeter, 202 is a second laser Doppler velocimeter, and 300 is a personal computer. Reference numeral 1 denotes a concrete structure to be inspected by the inspection apparatus 10.

The inspection apparatus 10 according to the embodiment of the present invention is roughly composed of a first laser Doppler velocimeter 201 and a second laser Doppler velocimeter that are fixed at two end positions of an inspection target region (shaded portion) in the concrete structure 1. 202, a striking vibrator 100 that strikes the surface of the concrete structure 1, and a personal computer 300 that processes data acquired by the first laser Doppler speedometer 201 and the second laser Doppler speedometer 202. Yes.

  The hitting vibrator 100 hits the surface of the concrete structure 1 to be inspected at a predetermined frequency (frequency) by a hitting part main body (striking protrusion). In the inspection apparatus 10 according to the present embodiment, the hitting portion main body is vibrated at 11 kHz to hit the surface of the concrete structure 1. However, the characteristics of the concrete structure 1 to be inspected and the target crack depth Accordingly, it is preferable to appropriately change the vibration frequency of the hitting projection main body. The inspection apparatus 10 according to the present embodiment is configured such that the impact position and impact vibration frequency of the impact vibrator 100 are also input to the personal computer 300 by an appropriate method.

  The physical quantity desired to be measured by the first laser Doppler velocimeter 201 and the second laser Doppler velocimeter 202 is firstly the amplitude of vibration at a predetermined position in the concrete structure to be inspected. The laser Doppler velocimeter is a device that detects the speed, and the displacement, that is, the amplitude, can be calculated by time-integrating the speed at a predetermined position. Conversely, the physical quantity to be measured may be velocity or acceleration. Here, the first laser Doppler velocimeter 201 detects the vibration speed of the first position in the concrete structure, and the second laser Doppler velocimeter 202 detects the vibration speed of the first position in the concrete structure.

  The first laser Doppler velocimeter 201 is disposed at a predetermined position, and detects the speed as a physical quantity related to the vibration of the concrete structure 1 at the first position. Similarly, the second laser Doppler velocimeter 202 is disposed at a predetermined position, and detects the speed as a physical quantity related to the vibration of the surface (inspection surface) of the concrete structure 1.

  Further, the laser Doppler velocimeter used in the inspection apparatus 10 according to the present embodiment such as the first laser Doppler velocimeter 201 and the second laser Doppler velocimeter 202 transmits physical quantity data relating to the detected vibration to the personal computer 300. A possible data output is provided.

  As the personal computer 300, a general computer that is currently popular can be used, but in this embodiment, at least a physical quantity related to vibration transmitted from the first laser Doppler velocimeter 201 and the second laser Doppler velocimeter 202. A personal computer 300 having interface means capable of receiving data is used.

  Further, the first laser Doppler velocimeter 201 and the second laser Doppler velocimeter 202 are respectively installed on the three-dimensional pan head 210. The three-dimensional pan head 210 can aim a laser Doppler velocimeter installed on the three-dimensional pan head 210 at a predetermined position of the concrete structure 1 to be inspected. Further, the three-dimensional head 210 is communicably connected to the personal computer 300 so that data relating to which position of the concrete structure 1 the laser Doppler velocimeter is aimed at can be transmitted. It has become. Further, the three-dimensional head 210 can control the aiming position of the laser Doppler velocimeter by a control signal from the personal computer 300.

Further, the personal computer 300 holds a CPU for processing physical quantity data relating to vibration acquired from the first laser Doppler velocimeter 201 and the second laser Doppler velocimeter 202 and a program operating on the CPU. It has basic information processing mechanisms such as RAM, which is a work area for ROM and CPU. The personal computer 300 includes display means such as a display capable of displaying the result of data processing.

  As an inspection procedure by the inspection apparatus 10 according to the present embodiment configured as described above, the impacting vibrator 100 is arranged at a predetermined position in the inspection target region, and the impacting vibrator 100 hits the position. The vibration is generated, and the vibration is acquired by the first laser Doppler velocimeter 201 and the second laser Doppler velocimeter 202. Next, for example, the position of the inspection object acquired by the second laser Doppler velocimeter 202 is shifted, and similarly acquired by the first laser Doppler velocimeter 201 and the second laser Doppler velocimeter 202. This is sequentially repeated to obtain mapping data related to the concrete structure 1 to be inspected.

  Next, data processing in the inspection apparatus 10 according to the present embodiment configured as described above will be described. FIG. 2 is a diagram showing an outline of the flow of data processing in the inspection apparatus 10 according to the embodiment of the present invention.

In FIG. 2, when data processing is started in step S100, a physical quantity related to vibration of the concrete structure 1 surface is acquired by the first laser Doppler velocimeter 201 in step S101. In the next step S102, correction according to the distance r ₁ between the impact position by the impact vibrator 100 and the first laser Doppler velocimeter 201 is performed to obtain the first corrected physical quantity. Here, the correction in step S102 is based on the physical quantity according to the distance while the physical quantity related to vibration is transmitted from the impact position by the impact vibrator 100 to the first position where the first laser Doppler velocimeter 201 is fixed. It is a correction that compensates for the attenuation. That is, the physical quantity in which the distance attenuation based on the distance between the impact position and the first position is corrected is the first corrected physical quantity. In step S103, a process of extracting the first physical quantity (A1) related to the surface wave from the first corrected physical quantity is executed.

In step S <b> 104, a physical quantity related to vibration of the concrete structure 1 surface is acquired by the second laser Doppler velocimeter 202. In the next step S105, correction according to the distance r ₂ between the impact position by the impact vibrator 100 and the second laser Doppler velocimeter 202 is performed, and a second corrected physical quantity is acquired. As before, the correction in step S105 is performed according to the distance while the physical quantity related to vibration is transmitted from the impact position by the impact vibrator 100 to the second position where the second laser Doppler velocimeter 202 is fixed. This is a correction to compensate for the attenuation of the physical quantity. That is, the physical quantity in which the distance attenuation based on the distance between the impact position and the second position is corrected is the second corrected physical quantity. In step S106, a process of extracting the second physical quantity (A2) related to the surface wave from the second corrected physical quantity is executed.

  In step S107, (second physical quantity A2) / (first physical quantity A1) is calculated. In the present embodiment, the calculation is performed such that the second physical quantity is divided by the first physical quantity. However, the calculation may be performed so that the first physical quantity is divided by the second physical quantity. Moreover, what is necessary is just to take a difference, when displaying a logarithm of speed.

In step S108, the calculated value in step S107 corresponding to the impact position is mapped. Here, a data acquisition example for obtaining mapping data related to the concrete structure 1 to be inspected will be described. FIG. 3 is a diagram illustrating an example of data acquisition of an inspection target area for obtaining mapping in the concrete structure 1. In the example of FIG. 3, the physical quantity acquired by the first laser Doppler velocimeter 201 is one point, and the physical quantity acquired by the second laser Doppler velocimeter 202 is a plurality of lattice points as shown. is there. That is, in the example of FIG. 3, the points acquired by the first laser Doppler velocimeter 201 are fixed, and the points acquired by the second laser Doppler velocimeter 202 are sequentially shifted and scanned.

  In the example of FIG. 3, the point acquired by the first laser Doppler velocimeter 201 is fixed, and the point acquired by the second laser Doppler velocimeter 202 is moved. The point acquired by the laser Doppler velocimeter 201 may be moved, the point acquired by the second laser Doppler velocimeter 202 may be fixed, the point acquired by the first laser Doppler velocimeter 201, and the second laser You may make it move both the points acquired with the Doppler speedometer 202. FIG.

  In step S109, it is determined whether or not mapping has been completed for all of the predetermined inspection target areas. When the determination in step S109 is NO, the process proceeds to step S110, the point acquired by the second laser Doppler velocimeter 202 is moved, and the process returns to the loop for acquiring the physical quantity of the next movement destination.

  On the other hand, when the determination in step S109 is YES, the process proceeds to step S111, and all mapping results of the inspection target area are displayed based on the map. In step S111, the crack depth and position are specified based on the map. In step S112 following step S111, the process ends.

In step S111, the crack depth and position are specified based on the map. In the inspection apparatus according to the present invention, the method for specifying the crack depth and position is, for example, “New measurement technology of crack depth using surface wave”, JSDNI Symposium “Expectation for non-destructive inspection of concrete structures”, pp. The methods disclosed in 243-252, 2003 and the like can be appropriately employed. Step S111 is expressed in the claims as crack depth specifying means and crack position specifying means.

  Here, the process of extracting the first physical quantity (A1) in step S103 and the process of extracting the second corrected physical quantity (A2) in step S106 will be described in more detail. FIG. 4 shows the distance attenuation correction in steps S102 and S105 for the physical quantities acquired by the first laser Doppler velocimeter 201 (FIG. 4A) and the second laser Doppler velocimeter 202 (FIG. 4B). It is a figure which shows the performed vibration waveform schematically.

In FIG. 4, the waveform with the smaller amplitude is the P wave (longitudinal wave component) detected by the first laser Doppler velocimeter 201, and the waveform with the larger amplitude is detected by the first laser Doppler velocimeter 201. It is a surface wave (component). The distance r ₁ between the hitting vibrator 100 and the first laser Doppler velocimeter 201 is known, and the frequency at which the hitting vibrator 100 hits the surface of the concrete structure 1 and the hitting vibrator 100 hits the surface. Since the time t _{1 at} which the collision starts is controlled, the time t ₂ when the P wave reaches the first laser Doppler velocimeter 201 and the time t when the surface wave reaches the first laser Doppler velocimeter 201. The outline of ₃ can be predicted to some extent.

Therefore, in the inspection apparatus 10 according to an embodiment of the present invention, for small wave amplitude reaching the time t ₂ before and after the first laser Doppler velocimeter 201 does not acquire as data,
Amplitude data of a large amplitude wave that reaches the first laser Doppler velocimeter 201 around time t ₃ is extracted as a physical quantity related to the magnitude of the surface wave. More specifically, the first amplitude A ₁ of the wave having a large amplitude shown in FIG.
Obtained as the first physical quantity A ₁ extracted from the measurement at 01. The process in which the inspection apparatus 10 according to the present embodiment extracts such a physical quantity is referred to as a filter process.

Similarly, the distance r ₂ between the hitting vibrator 100 and the second laser Doppler velocimeter 202 is known, and the frequency at which the hitting vibrator 100 hits the surface of the concrete structure 1, the hitting vibrator. because time 100 starts striking impact is controllable, in the inspection apparatus 10 according to this embodiment, the small wave amplitude to reach the time t ₄ before and after the second laser Doppler velocimeter 202 acquired as data without the amplitude data of large wave amplitude reaches the time t ₅ before and after the second laser Doppler velocimeter 202, second laser Doppler velocimeter 2
This is acquired as a second physical quantity A ₂ related to the magnitude of the surface wave at 02.

  According to the inspection apparatus 10 according to the present invention, based on a ratio of physical quantities related to the magnitude of surface waves (or a difference in the case of logarithmic display) acquired from a plurality of laser Doppler velocimeters, it relates to cracks in the inspection target region. Information can be estimated. According to the inspection apparatus 10 according to the present invention, it is not necessary to perform an inspection in the vicinity of a crack, and the time required for the analysis is short, and it is possible to efficiently inspect a wide range of structure surfaces. . And according to such an inspection device 10 concerning the present invention, a rational repair plan can be performed.

  Next, the measurement principle used by the inspection apparatus 10 according to the embodiment of the present invention will be described. FIG. 5 is a diagram for explaining the outline of the measurement principle of the inspection apparatus 10 according to the embodiment of the present invention, and FIG. 6 is a diagram showing the outline of the vertical distribution of surface waves. In the measurement principle described below, the attenuation of surface wave energy due to cracking is discussed.

The attenuation amount of the surface wave due to the crack (slit) can be theorized as the energy of the surface wave whose propagation is inhibited by the slit is attenuated. It is assumed that the amplitude distribution of the surface wave having the vertical amplitude is as shown in FIG.
The distribution formula at this time is

（１）
として現すことができる。

(1)
Can appear as

  Here, λ is the wavelength of the input wave, and D is the depth of the crack (slit). Assuming that the amplitude is 1/4 when the slit depth is equal to the wavelength, the coefficient A is A = −1.3863.

（２）

(2)

（３）
スリット深さがＤの時、その深さまでに分布するエネルギー量は、

(3)
When the slit depth is D, the amount of energy distributed up to that depth is

（４）
である。なお、全エネルギーは、Ｄ→∞とすれば良いので、Ｅ_o＝−λ／２Ａである。減
衰量の比率は、

(4)
It is. Since the total energy may be D → ∞, E _o = −λ / 2A. The attenuation ratio is

（５）
となる。
スリット通過後は、このエネルギーで再び表面波として振幅分布する。すなわち、

(5)
It becomes.
After passing through the slit, the amplitude is again distributed as a surface wave with this energy. That is,

（６）
これから、ひび割れ（スリット）深さＤの時、測定した振動の減衰量（ｄＢ）は、

(6)
From this, when the crack (slit) depth is D, the measured vibration attenuation (dB) is:

（７）
となる。なおｕは、ひび割れ（スリット）に関係なく上下方向振動成分を持つ表面波の深さＤでの振幅である。

(7)
It becomes. Note that u is the amplitude at the depth D of the surface wave having the vertical vibration component regardless of the crack (slit).

DESCRIPTION OF SYMBOLS 1 ... Concrete structure 10 ... Inspection apparatus 100 ... Impacting vibrator 110 ... Impacting vibrator 201 with a positional information transmission function ... 1st laser Doppler velocimeter 202 ... 2nd Laser Doppler speedometer 210 ... 3D pan head 300 ... Personal computer

Claims (4)

A striking vibrator that strikes a predetermined position on the inspection surface at a predetermined frequency;
A first laser Doppler velocimeter for detecting a physical quantity related to vibration of the inspection surface at a first position of the inspection surface;
A second laser Doppler velocimeter for detecting a physical quantity related to vibration of the inspection surface at a second position of the inspection surface;
The physical quantity relating to the vibration of the inspection surface detected by the first laser Doppler velocimeter is corrected according to the distance between the impact position by the impact oscillator and the first position, and First correction means for obtaining a corrected physical quantity;
Correcting a physical quantity related to the vibration of the inspection surface detected by the second laser Doppler velocimeter according to a distance between the impact position by the impact oscillator and the second position; Second correction means for obtaining a corrected physical quantity;
First filter means for extracting a first physical quantity related to the magnitude of the surface wave from the first corrected physical quantity obtained by the first correction means;
Second filter means for extracting a second physical quantity related to the magnitude of the surface wave from the previous second corrected physical quantity detected by the second laser Doppler velocimeter;
Calculating means for calculating a ratio between the first physical quantity extracted by the first filter means and the second physical quantity extracted by the second filter means;
An inspection apparatus comprising: display means for displaying the ratio calculated by the calculating means in correspondence with the impact position by the impact vibrator. The crack depth identifying means for identifying the crack depth from the first physical quantity extracted by the first filter means and the second physical quantity extracted by the second filter means. The inspection device described. The crack position specifying means for specifying a crack position from the first physical quantity extracted by the first filter means and the second physical quantity extracted by the second filter means. Inspection device. A striking vibrator that strikes a predetermined position on the inspection surface at a predetermined frequency;
A plurality of laser Doppler velocimeters for detecting physical quantities related to vibration of the inspection surface;
Depending on the physical quantity related to the vibration of the inspection surface detected by the plurality of laser Doppler velocimeters, depending on the distance between the striking position by the striking vibrator and the fixed positions of the plurality of laser Doppler velocimeters Correcting means for obtaining a plurality of corrected physical quantities,
Filter means for extracting a plurality of physical quantities related to the magnitude of the surface wave from the plurality of corrected physical quantities obtained by the correcting means;
Calculating means for calculating a ratio of any two physical quantities of the plurality of physical quantities extracted by the filter means;
An inspection apparatus comprising: display means for displaying the ratio calculated by the calculating means in correspondence with the impact position by the impact vibrator.

Images