JP2010271253A - Minute displacement display device and abnormal vibration monitoring system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a minute displacement display device which is arranged without wiring and can detect the vibration of a building, and to provide an abnormal vibration monitoring system using the same for the building. <P>SOLUTION: The minute displacement display device 1 is attached directly or indirectly to an object to be measured, and it includes a fixed-side moire slit plate 11 wherein a plurality of parallel lines are given, a vibration transmitting member 14a which is attached directly or indirectly to an object to be measured, a vibrator 15 fixed to the vibration transmitting member 14a, and a movable-side moire slit plate 12 wherein a plurality of fixed parallel lines are given to the vibrator 15. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a minute displacement display device using moiré fringes and an abnormal vibration monitoring system for a building using the same.

  Buildings such as factories, buildings, bridges, etc. may become obsolete due to secular change, resulting in strength problems such as insufficient strength, so it is necessary to regularly monitor the state of the building and perform maintenance management. is there.

  As a method for monitoring the state of a building, there is a method for detecting a vibration of a building and judging a defect or the like (for example, Patent Document 1). When the vibration of the building is detected by the vibration sensor and it is detected that the building is vibrating different from the normal state, the structure of the building is abnormal, such as damage or aging. Deciding.

JP-A-9-178547

  Since the target building is very large, there is a problem that it is difficult to arrange sensors for detecting abnormalities at various locations by arranging wiring for power supply and signal transmission in the building.

  The present invention has been made in view of the above-described matters, and an object of the present invention is to provide a minute displacement display device that can be arranged in a building without using wiring and can detect vibrations of the building, and the same. It is to provide an abnormal vibration monitoring system for a building.

The minute displacement display device of the first aspect according to the present invention is:
A fixed-side moire slit plate attached directly or indirectly to the object to be measured and provided with a plurality of parallel lines;
A vibration transmission member attached directly or indirectly to the object to be measured;
A vibrator fixed to the vibration transmitting member;
A moving-side moire slit plate fixed to the vibrator and provided with a plurality of parallel lines,
The fixed side moire slit plate and the moving side moire slit plate are arranged so as to overlap each other so that the angles of the parallel lines are different, and express moire fringes,
Sliding the moiré slit plate on the moving side by displacement of the vibrator due to vibration of the measurement target via the vibration transmitting member;
The displacement amount of the moire fringes is displayed larger than the displacement amount of the vibrator.

The minute displacement display device of the second aspect according to the present invention is:
A fixed-side moire lattice plate that is directly or indirectly attached to the object to be measured and is provided with a lattice;
A vibration transmission member attached directly or indirectly to the object to be measured;
A vibrator fixed to the vibration transmitting member;
A moving-side moire lattice plate fixed to the vibrator and provided with a lattice,
The fixed-side moire lattice plate and the moving-side moire lattice plate are arranged so as to overlap each other so that the angles of the lattices are different, and express moire fringes,
Sliding the moire lattice plate on the moving side by displacement of the vibrator due to vibration of the object to be measured via the vibration transmitting member;
Displaying the displacement amount of the moire fringes larger than the displacement amount of the vibrator;
It is characterized by that.

The minute displacement display device of the third aspect according to the present invention is:
A fixed-side moire lattice plate that is directly or indirectly attached to the object to be measured and is provided with a lattice;
A moving-side moire lattice plate with a lattice;
A vibration transmitting member that connects the fixed side moire lattice plate and the moving side moire lattice plate;
The fixed-side moire lattice plate and the moving-side moire lattice plate are arranged so as to overlap each other so that the angles of the lattices are different, and express moire fringes,
Rotating the moving-side moire grating plate around a predetermined point of the fixed-side moire grating plate with the vibration of the object to be measured via the vibration transmitting member, and changing the width of the moire fringes for display.
It is characterized by that.

  A plurality of the vibration transmitting members may be arranged concentrically around a predetermined point of the fixed side moire lattice plate.

The abnormal vibration monitoring system for a building according to the present invention is:
The above-described minute displacement display device installed in a building,
An imaging device that continuously captures moire fringes expressed in the minute displacement display device;
An arithmetic device that performs image processing of the moiré fringes captured continuously and calculates vibration data based on the displacement of the moiré fringes;
A collation device for collating the reference vibration data calculated in advance with the calculated vibration data;
It is characterized by providing.

  Further, the calculation device may calculate the vibration data by calculating an acceleration from a displacement amount of the moire fringes.

  In the minute displacement display device according to the present invention, the displacement of the vibrator based on the minute vibration of the measurement target can be enlarged and displayed by moire fringes. This leads to visually recognizing minute vibrations of the measurement target that cannot be visually recognized.

  In the abnormal vibration monitoring system for a building according to the present invention, the above-described minute displacement display device is installed in the building, the building vibration data based on the displacement of the moire fringe is calculated, and the reference vibration of the building in a normal state is calculated. Matching with data. This makes it possible to determine whether or not abnormal vibration has occurred in the building, and is effective in monitoring the state of buildings such as bridges, factories, buildings, and the like.

1 is an external perspective view showing a schematic configuration of a minute displacement display device according to Embodiment 1. FIG. FIG. 3 is an exploded perspective view showing a schematic configuration of the minute displacement display device according to the first embodiment. It is a top view of (A) fixed side moire slit board of the micro displacement display device concerning Embodiment 1, and (B) movement side moire slit board. 2 is a plan view of the minute displacement display device according to Embodiment 1. FIG. 6 is a plan view showing the displacement of moire fringes of the minute displacement display device according to Embodiment 1. FIG. 6 is an external perspective view showing a schematic configuration of a minute displacement display device according to Embodiment 2. FIG. 4 is an exploded perspective view showing a schematic configuration of a minute displacement display device according to Embodiment 2. FIG. It is a top view of the (A) fixed side moire lattice board of the micro displacement display device which concerns on Embodiment 2, and the (B) movement side moire lattice plate. 6 is a plan view of moire fringes of a minute displacement display device according to Embodiment 2. FIG. FIG. 10 is a plan view showing the displacement of moire fringes of the minute displacement display device according to the second embodiment. FIG. 10 is a plan view showing the displacement of moire fringes of the minute displacement display device according to the second embodiment. 10 is an external perspective view showing a schematic configuration of a minute displacement display device according to Embodiment 3. FIG. FIG. 10 is an exploded perspective view showing a schematic configuration of a minute displacement display device according to a third embodiment. 6 is a plan view of a minute displacement display device according to Embodiment 3. FIG. 10 is a plan view showing a change in moire fringes of a minute displacement display device according to Embodiment 3. FIG. It is a schematic block diagram which shows the example of 1 form of the abnormal vibration monitoring system of the building which concerns on Embodiment 4. FIG. 10 is a flowchart illustrating an operation of the abnormal vibration monitoring system for a building according to the fourth embodiment. 10 is a flowchart illustrating an operation of the abnormal vibration monitoring system for a building according to the fourth embodiment. It is a mechanical characteristic figure of a vibrator of a minute displacement display device used for an example. It is a figure which shows the relationship between time and acceleration in an Example. It is a figure which shows the relationship between the time in an Example, and the displacement of a vibrator.

  Hereinafter, a minute displacement display device according to an embodiment of the present invention and an abnormal vibration monitoring system for a building using the same will be described in detail. First, a minute displacement display device will be described.

(Embodiment 1)
The minute displacement display device according to the first embodiment will be described with reference to the drawings. As shown in the external perspective view of FIG. 1 and the exploded perspective view of FIG. 2, the minute displacement display device 1 includes a fixed side moire slit plate 11, a moving side moire slit plate 12, a base 13, and a vibration transmitting member 14a. , 14b and the vibrator 15.

  The base 13 is a member fixed to a measurement target such as a building. For this reason, the relative position of the base 13 and the measurement target does not change.

  The vibration transmission members 14 a and 14 b connect the base 13 and the vibrator 15. The vibration transmitting members 14a and 14b transmit the vibration of the measurement target to the vibrator 15, and have a role of deforming itself to displace the vibrator 15. Therefore, the vibration transmitting members 14a and 14b are preferably members having a high deformation rate and elastic modulus. In addition, it is preferable to use a member having a high damping force because the vibrator 15 preferably has a role of damping the vibrator 15 so that the vibrator 15 does not vibrate permanently due to the inertial force due to the transmitted vibration.

  Examples of the transmission member 14a, 14b include various members such as a metal wire, a metal thin plate, a resin rod-like member such as rubber or plastic, or a plate-like member. Moreover, you may be comprised combining the spring and the damper.

  The vibrator 15 vibrates in response to the vibration of the measurement target transmitted through the vibration transmitting members 14a and 14b. The vibrator 15 has a role of displacing a moving moire slit plate 12 to be described later when the relative position is displaced with respect to the measurement target. The vibration of the object to be measured is transmitted to the vibrator 15 via the vibration transmitting members 14a and 14b, and the vibrator 15 vibrates in response to the vibration. That is, the relative position of the vibrator 15 changes with respect to the measurement target. For this reason, the vibrator 15 needs to have a weight so that the relative position with respect to the measurement target can be easily changed. For the specific relationship between the weight of the vibrator 15 and the elastic modulus and damping force of the vibration transmitting members 14a and 14b, refer to the literature “Measuring Engineering; Osamu Taniguchi, Yasuo Inugi; Morikita Publishing Co., Ltd .; You can refer to it.

  The fixed-side moire slit plate 11 is fixed to the base 13 so that the relative position with respect to the object to be measured does not change.

  The moving side moire slit plate 12 is fixed to the vibrator 15. As described above, since the vibrator 15 vibrates and displaces, the moving side moire slit plate 12 is displaced following the vibrator 15. For this reason, the moving-side moire slit plate 12 has a mechanism in which the relative position changes with respect to the fixed-side moire slit plate 11.

  The fixed-side moire slit plate 11 and the moving-side moire slit plate 12 are made of colorless rectangular plate-like members, and a plurality of straight lines are provided in parallel as shown in FIG. The plurality of straight lines applied to the fixed-side moire slit plate 11 and the moving-side moire slit plate 12 are all provided at equal intervals with the same line width.

  The fixed-side moire slit plate 11 is provided with a plurality of straight lines parallel to the x-axis direction. One moving side moire slit plate 12 is provided with a plurality of straight lines that are slightly inclined with respect to the x-axis direction.

  FIG. 4 shows a plan view of the minute displacement display device 1. As described above, the fixed-side moire slit plate 11 and the moving-side moire slit plate 12 are arranged so that the angles of a plurality of straight lines applied to each other are different from each other. , M3 is expressed.

  FIG. 5 shows the displacement state of the moire fringes M1, M2, and M3 when the vibrator 15 vibrates in response to vibration from the measurement target and is displaced in the y-axis direction. When the vibrator 15 is displaced Δy downward in the y-axis direction as indicated by an arrow, the moving-side moire slit plate 12 fixed to the vibrator 15 follows and is displaced downward in the y-axis direction by Δy. Then, the moire fringes M1, M2, and M3 are displaced by Δx to the left in the x-axis direction.

For example, the pitch of a plurality of straight lines applied to the fixed-side moire slit plate 11 and the moving-side moire slit plate 12 is Pl, and the pitch of moire fringes that appears when each straight line intersects at an angle θ. Is represented by the following formula (1).

  Assuming that θ is 0.5 °, PM is approximately 114.593 Pl, so that the displacement amount Δx of the moire fringes M1, M2, and M3 is approximately 115 times (magnification) of the displacement amount Δy of the vibrator 15. .

  As described above, the displacement amount Δx of the moire fringes M1, M2, and M3 is larger than the displacement amount Δy of the vibrator 15, so that the minute displacement of the vibrator 15 is enlarged and displayed. be able to. This means that it is possible to visually recognize invisible vibration generated in the measurement target, and it is possible to visually grasp whether abnormal vibration has occurred in the measurement target described later. .

  On the other hand, when the vibrator 15 moves upward in the y-axis direction, the moire fringes M1, M2, and M3 move to the right in the x-axis direction, contrary to the above.

  In the above description, the plurality of straight lines of the moving-side moire slit plate 12 are inclined, but conversely, the plurality of straight lines of the fixed-side moire slit plate 11 may be inclined.

  Moreover, although the case where the fixed side moire slit plate 11 is indirectly attached to the measurement target has been described using the base 13, the base 13 is not necessarily used. For example, the vibration transmitting members 14a and 14b and the fixed-side moire slit plate 11 may be directly fixed to the measurement target.

  Further, the fixed-side moire slit plate 11 and the moving-side moire slit plate 12 may be arranged in close contact with each other or may be arranged apart from each other. When the fixed-side moire slit plate 11 and the moving-side moire slit plate 12 are stacked in close contact with each other, the movement of the moving-side moire slit plate 12 is not impaired, and the vibration of the vibrator 15 is not permanent due to inertial force. It is good to arrange it over a viscous substance such as oil or gel.

(Embodiment 2)
The micro displacement display device 2 according to the second embodiment will be described with reference to the external perspective view of FIG. 6 and the exploded perspective view of FIG.

  The minute displacement display device 2 includes a base 13, a vibration transmission member 14, a vibrator 15, a fixed side moire lattice plate 21, and a moving side moire lattice plate 22.

  Since the base 13 and the vibrator 15 are the same as those in the first embodiment, the description thereof is omitted.

  The vibration transmission member 14 is an L-shaped member, and functions and materials are the same as those in the first embodiment described above. However, in the first embodiment, the vibration transmission member 14 corresponds to the uniaxial displacement of the vibrator 15. However, the present embodiment is different in that it corresponds to a biaxial displacement.

  The fixed side moire lattice plate 21 and the moving side moire lattice plate 22 are arranged so as to overlap each other.

  The fixed-side moire lattice plate 21 is fixed to the base 13 so that the relative position with respect to the measurement target does not change.

  On the other hand, the moving-side moire lattice plate 22 is fixed to the vibrator 15 and is displaced following the displacement of the vibrator 15.

  The fixed-side moire lattice plate 21 and the moving-side moire lattice plate 22 are colorless plate-like members, and are each provided with a lattice as shown in FIG. The line width of each grating and the pitch of the grating are all the same. The grating applied to the moving-side moire grating plate 22 is inclined with respect to the grating applied to the fixed-side moire grating plate 21 at a different angle.

  Since the fixed-side moire lattice plate 21 and the moving-side moire lattice plate 22 are arranged so that the angles of the lattices applied to each other are different, the bands intersect as shown in the plan view of FIG. The latticed moire fringes M appear.

  FIG. 10 shows how the moire fringes M are displaced when a force in the y-axis direction is applied to the vibrator 15 by the vibration transmitted from the measurement object. When the vibrator 15 is subjected to vibration from the measurement target and the vibrator 15 is displaced downward in the y-axis direction by Δy, the moving-side moire grating plate 22 fixed to the vibrator 15 also follows and similarly Δy in the downward direction in the y-axis. It is displaced so much. Then, the moire fringes M extending in the y-axis direction are displaced by Δx leftward in the x-axis direction.

  The displacement amount Δx of the moiré fringes M is much larger than the displacement amount Δy of the vibrator 15 as in the first embodiment, so that the displacement of the minute vibrator 15 can be enlarged and displayed. This means that it is possible to visually recognize invisible vibrations that occur in the measurement target. When the vibrator 15 is displaced upward in the y-axis direction, the moire fringes M extending in the y-axis direction are displaced rightward in the x-axis direction.

  On the other hand, FIG. 11 shows the displacement of the moire fringes M when a force in the x-axis direction is applied to the vibrator 15 by the vibration transmitted from the measurement target. When vibration is received from the object to be measured and the vibrator 15 is displaced by about Δx in the right direction in the x-axis direction, the moving-side moire lattice plate 22 fixed to the vibrator 15 is similarly displaced. In this case, the moire fringes M extending in the x-axis direction are displaced by Δy downward in the y-axis direction. Conversely, when the vibrator 15 is displaced leftward in the x-axis direction, the moire fringes M extending in the x-axis direction are displaced upward in the y-axis direction.

(Embodiment 3)
The micro displacement display device 3 according to the third embodiment will be described with reference to the external perspective view of FIG. 12 and the exploded perspective view of FIG.

  The minute displacement display device 3 includes a vibration transmission member 14, a fixed side moire lattice plate 21, and a moving side moire lattice plate 22.

  The fixed-side moire lattice plate 21 is attached to the measurement target directly or indirectly. The relative positional relationship of the fixed-side moire lattice plate 21 with respect to the measurement target does not change.

  The moving-side moire lattice plate 22 is connected to the fixed-side moire lattice plate 21 via the vibration transmitting members 14 arranged at the four corners.

  Four vibration transmitting members 14 are arranged on a concentric circle with a predetermined point as the center point, and the vibration transmitting member 14 has a role of transmitting vibration from the measurement target to the moving-side moire lattice plate 22. Thereby, the moving-side moire lattice plate 22 rotates along the surface of the fixed-side moire lattice plate 21 with a predetermined point as the central axis.

  The fixed-side moire lattice plate 21 and the moving-side moire lattice plate 22 are each provided with a lattice, as in the second embodiment, and the fixed-side moire lattice plate 21 and the moving-side moire lattice plate 22 are respectively Since the grids are stacked at different angles, a grid-like moire fringe M appears as shown in the plan view of FIG.

  The operation of the minute displacement display device 3 will be described with reference to FIG. Vibration generated from the object to be measured is transmitted to the moving moire lattice plate 22 via the vibration transmitting member 14. Then, since the vibration transmission member 14 is connected to the square of the moving side moire lattice plate 22, the moving side moire lattice plate 22 rotates around the center.

  When the moving-side moire lattice plate 22 rotates counterclockwise by θ, the pitch of the moire fringes M is displayed large. Since the pitch of the moiré fringes M changes greatly by a slight rotation of the moving-side moire grating plate 22, a minute rotational displacement of the moving-side moire grating plate 22 based on the measurement target can be enlarged and observed. On the other hand, when the moving-side moire grating plate 22 rotates clockwise, the pitch of the moire fringes M is reduced because the angles of the respective gratings coincide with each other.

(Embodiment 4)
Next, the abnormal vibration monitoring system for buildings according to Embodiment 4 using the above-described minute displacement display device will be described. FIG. 16 is a schematic configuration diagram illustrating an example of an abnormal vibration monitoring system.

  The minute displacement display device 4 installed on the upper part of the bridge girder 42, the photographing device 31 for continuously photographing the minute displacement display device 4 at high speed, the image photographed by the photographing device 31 are processed, and the calculation and verification of vibration data are performed. And a processing device 32.

  As the minute displacement display device 4, any one of the minute displacement display devices 1 to 3 described above may be used.

  The imaging device 31 is arranged so that the displacement of the moire fringes of the minute displacement display device 4 can be imaged. As the imaging device 31, a high-speed camera that can capture a large number of images per unit time may be used. An image photographed by the photographing device 31 is sent to the processing device 32 as image data.

  The processing device 32 is a memory (not shown) that stores pre-computed reference vibration data, and processing of the image data that is sent, and computation of vibration data based on the displacement of moire fringes. An apparatus (not shown) and a checking device (not shown) for checking reference vibration data and calculated vibration data are provided.

  Next, an outline of processing of the abnormal vibration monitoring system for buildings will be described with reference to the flowcharts shown in FIGS. 17 and 18.

  First, as shown in the flowchart of FIG. 17, reference vibration data that is vibration data of the bridge at the normal time is obtained.

  First, photographing S11 of moire fringes is performed by the photographing device 31. The image photographed by the photographing device 31 is sent to the processing device 32, where image processing S12 and reference vibration data computation S13 are performed by the computation device.

  In the arithmetic device, the acceleration of the bridge to be measured is calculated from the displacement amount of the moire fringes, and the reference vibration data based on the acceleration is calculated. As the reference vibration data, for example, a characteristic vibration characteristic or the like possessed by the bridge to be measured, which is obtained by Fourier transform and mode analysis of the acceleration, may be used.

  Note that the acceleration of the bridge to be measured is obtained by dividing the displacement amount of the moire fringes by the enlargement factor described in the first embodiment, thereby obtaining the displacement amount of the vibrator 15 and the natural vibration of the minute displacement display device 4. It can be calculated from the product of the square of the number. If necessary, the acceleration and the displacement of the measurement target can be calculated by integrating the obtained acceleration. Therefore, the reference vibration data may be created using these.

  The reference vibration data calculated as described above is stored in the memory S14.

  Subsequently, vibration data is acquired according to the flowchart shown in FIG. 18, and it is monitored whether abnormal vibration has occurred in the bridge.

  In the same manner as described above, Moire fringe photographing S21 is performed by the photographing apparatus. Then, processing S22 of the obtained image is performed, and calculation S23 of vibration data is performed. Moire fringe imaging S21, image processing S22, and vibration data calculation S23 are the same as the above-described reference vibration data calculation method.

  A collation S24 is performed to determine whether or not the vibration data obtained in this way matches the reference vibration data. If the vibration data and the reference vibration data match, the process returns to S21 to continue shooting. When the vibration data and the reference vibration data do not match, it is determined that the bridge is in an abnormal state, and the notification means 25 notifies that the bridge is abnormal. As the notification means, various means such as display, light emission, and sound may be used.

  Although it is difficult to obtain image data that can identify the displacement of the bridge due to vibration by simply photographing the bridge with the photographing apparatus, in the present embodiment, by using a micro displacement display device, the above-described image data can be obtained. Thus, it is possible to acquire image data that can identify the displacement of the vibrator based on the vibration of the bridge. The vibration of the bridge is transmitted to the vibrator and displaced, and thereby the moving side moire lattice plate 22 or the moving side moire slit plate 12 is displaced, so that the moire fringes are displaced. Therefore, it is possible to observe even a photographing apparatus arranged far away, and vibration data can be obtained from the photographed image.

  In addition, in the abnormal vibration monitoring system for buildings according to the present embodiment, a minute displacement display device that does not use an electrical signal is installed, so there is no need to send wiring or the like to the bridge. For this reason, maintenance is easy. Furthermore, since no electrical signal is used, the cost can be reduced compared to a vibration detection sensor.

  When a plurality of measurements are performed, a plurality of minute displacement display devices 4 may be installed, and an imaging device 31 that photographs each minute displacement display device 4 may be installed.

  In the above, the vibration data calculated from acceleration is collated. However, it is limited to this as long as the vibration of the bridge in the normal state and the vibration of the bridge in the abnormal state can be collated. There is no. For example, data obtained by calculating the amplitude of the moire fringe, data obtained by calculating the frequency of the moire fringe, or data obtained by calculating the movement pattern of the moire fringe from the captured image as the reference vibration data and vibration data. You may make it collate.

  Further, whether or not the vibration data and the reference vibration data match each other may be provided with a threshold value to have a desired allowable range.

  In the present embodiment, the video from the imaging device 31 is transmitted to the processing device 32 by wire, but the video may be transmitted from the imaging device 31 to the processing device 32 by radio.

  Moreover, although the case where the abnormal vibration of the bridge is monitored has been described, the same applies to various buildings such as towers and buildings.

  A minute displacement display device having the same structure as that of the first embodiment was created, and acceleration data and displacement data were calculated from the displacement of moire fringes due to vibration.

  The pitch of a plurality of parallel straight lines applied to the fixed side moire slit plate and the moving side moire slit plate is 0.02 mm. The fixed-side moire lattice plate and the moving-side moire lattice plate are arranged so as to overlap each other at an angle of 0.003 rad. At this time, the pitch of the moire fringes that appear is about 6.7 mm, and the relative displacement of the moire fringes with respect to the displacement of the moving-side moire slit plate is enlarged by about 335 times. The material for the vibration transmitting member was duralumin 2017, and the vibrator was copper alloy C2081. The mass of this minute displacement display device is 25.9 g.

  First, the mechanical characteristics of the produced micro displacement display device were examined. A small displacement display device was vibrated freely, and the displacement of the vibrator was measured. The result is shown in FIG. The natural angular frequency was 314 rad / s (50 Hz), and the damping ratio was about 0.008.

  The base of this minute displacement display device was fixed on a vibrator and a vibration was applied. The vibration of the vibrator was a one-dimensional vibration with an amplitude of 1 mm or less and a frequency of 3 Hz. Further, under the same conditions, the vibration frequency was 5 Hz.

  The image was taken with a camera from a position approximately 400 mm away from the minute displacement display device, and the amount of displacement of moire fringes was measured from the taken image. This displacement amount was divided by the enlargement ratio of moire fringes (about 335 times in this micro displacement display device), and the displacement amount of the vibrator was calculated. Then, the acceleration of the vibrator, that is, the acceleration of the vibrator was obtained.

  The displacement of the moire fringes was photographed at 2000 fps using a high speed camera.

  In addition, the displacement of the vibrator was measured with a laser displacement meter in order to obtain a comparison with the data measured by the minute displacement display device. In addition, an LED was used to synchronize the high-speed camera and the laser displacement meter.

  The acceleration of the obtained vibrator is shown in FIG. It can be seen that accelerations of 3 Hz and 5 Hz, which are the same as the vibration frequency of the vibrator, are measured. In addition, although the vibration of 50 Hz is detected simultaneously, this frequency corresponds with the natural frequency of this micro displacement display device, and it is thought that the influence of the natural frequency has come out.

  FIG. 21 shows the relationship between the time obtained by integrating the acceleration shown in FIG. 13 and the displacement of the vibrator. The solid line is the displacement of the vibrator obtained from the acceleration, and the broken line is the displacement of the vibrator measured by a laser displacement meter. It can be confirmed that, at both 3 Hz and 5 Hz, the displacement of the vibrator obtained by using the minute displacement display device substantially coincides with the displacement of the vibrator measured by using the laser displacement meter.

  From these experimental results, in the micro displacement display device, the micro displacement of the vibrator based on the micro vibration of the measurement target can be enlarged and displayed with moire fringes, and the moire fringes are photographed and image processing is performed. Thus, the acceleration of moire fringes and the acceleration of the vibrator can be calculated. Thereby, it turns out that the abnormal vibration of a building can be monitored using a minute displacement display device.

  In the minute displacement display device, the displacement of the vibrator based on minute vibrations of a building such as a bridge can be enlarged and displayed by moire fringes. This leads to visually recognizing minute vibrations of the building that cannot be visually recognized. It is possible to determine whether abnormal vibration is occurring in the building by calculating the vibration data of the building based on the displacement of the moire fringes and comparing it with the reference vibration data of the building under normal conditions. It becomes. Therefore, it can be used when monitoring the state of buildings such as bridges, factories, buildings, etc. and performing maintenance management.

DESCRIPTION OF SYMBOLS 1 Minute displacement display device 2 Minute displacement display device 3 Minute displacement display device 4 Minute displacement display device 11 Fixed side moire slit plate 12 Moving side moire slit plate 13 Base 14 Vibration transmission member 14a Vibration transmission member 14b Vibration transmission member 15 Vibrator 21 Fixed side moire lattice plate 22 Moving side moire lattice plate 31 Imaging device 32 Processing device 41 Bridge 42 Bridge girder 43 Bridge pier M Moire stripe M1 Moire stripe M2 Moire stripe M3 Moire stripe

Claims (6)

A fixed-side moire slit plate attached directly or indirectly to the object to be measured and provided with a plurality of parallel lines;
A vibration transmission member attached directly or indirectly to the object to be measured;
A vibrator fixed to the vibration transmitting member;
A moving-side moire slit plate fixed to the vibrator and provided with a plurality of parallel lines,
The fixed side moire slit plate and the moving side moire slit plate are arranged so as to overlap each other so that the angles of the parallel lines are different, and express moire fringes,
Sliding the moiré slit plate on the moving side by displacement of the vibrator due to vibration of the measurement target via the vibration transmitting member;
Displaying the displacement amount of the moire fringes larger than the displacement amount of the vibrator;
A micro-displacement display device characterized by that. A fixed-side moire lattice plate that is directly or indirectly attached to the object to be measured and is provided with a lattice;
A vibration transmission member attached directly or indirectly to the object to be measured;
A vibrator fixed to the vibration transmitting member;
A moving-side moire lattice plate fixed to the vibrator and provided with a lattice,
The fixed-side moire lattice plate and the moving-side moire lattice plate are arranged so as to overlap each other so that the angles of the lattices are different, and express moire fringes,
Sliding the moire lattice plate on the moving side by displacement of the vibrator due to vibration of the object to be measured via the vibration transmitting member;
Displaying the displacement amount of the moire fringes larger than the displacement amount of the vibrator;
A micro-displacement display device characterized by that. A fixed-side moire lattice plate that is directly or indirectly attached to the object to be measured and is provided with a lattice;
A moving-side moire lattice plate with a lattice;
A vibration transmitting member that connects the fixed side moire lattice plate and the moving side moire lattice plate;
The fixed-side moire lattice plate and the moving-side moire lattice plate are arranged so as to overlap each other so that the angles of the lattices are different, and express moire fringes,
Rotating the moving-side moire grating plate around a predetermined point of the fixed-side moire grating plate with the vibration of the object to be measured via the vibration transmitting member, and changing the width of the moire fringes for display.
A micro-displacement display device characterized by that.   The micro displacement display device according to claim 3, wherein a plurality of the vibration transmitting members are arranged concentrically around a predetermined point of the fixed-side moire lattice plate. The minute displacement display device according to any one of claims 1 to 4, which is installed in a building;
An imaging device that continuously captures moire fringes expressed in the minute displacement display device;
An arithmetic device that performs image processing of the moiré fringes captured continuously and calculates vibration data based on the displacement of the moiré fringes;
A collation device for collating the reference vibration data calculated in advance with the calculated vibration data;
An abnormal vibration monitoring system for a building, comprising:   6. The abnormal vibration monitoring system for a building according to claim 5, wherein the calculation device calculates acceleration from a displacement amount of the moire fringes and calculates the vibration data. 7.

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