JPS63195508A - Strain measuring instrument - Google Patents

Abstract

PURPOSE:To easily and accurately measure strain at any place by arranging a half-mirror and a solid-state image pickup means on an object of measurement and a laser beam oscillator at a reference point. CONSTITUTION:The laser beam oscillator 3 is arranged at a specific measurement reference point of a bridge girder 2, plural mirrors 5 are arranged on a bridge floor plate 1 along the optical path 4 of a laser beam emitted by the oscillator 3, and two-dimensional CCD cameras 7 are arranged on optical paths 6 of reflection from the respective mirrors 5. Consequently, if the bridge floor plate 1 is displaced from a solid-line position to a broken-line position in a figure, the respective mirrors 5 and cameras 7 are also displaced as well, but the optical path 4 is fixed, so the irradiation positions of the optical paths 6 on the cameras 7 are displaced. For the purpose, the cameras 7 detects the displacement of the optical paths 6, whose data are analyzed to measure the quantity of strain.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a strain measuring device.

(Prior art) In general, strain is measured by bringing the measurement needle of a dial gauge, which is placed at an immovable position relative to the measurement reference position, into contact with the object to be measured, or by moving a water system suspended from the object to the measurement reference position. This is done by measuring.

(Problem to be solved by the invention) However, when trying to measure strain in bridge decks, structures, etc., for example, a support is required to place the dial gauge at a measurement reference position and an immovable position. However, in order to ensure accurate measurements, this support has the disadvantage of being extremely large. Furthermore, when a water-based system is used, it has the disadvantage that it cannot be used outdoors.

The present invention was made in response to these circumstances, and an object of the present invention is to provide a strain measuring device that can easily and accurately measure strain at any location.

[Structure of the Invention] (Means for Solving the Problems and Their Effects) That is, the strain measuring device of the present invention includes a laser beam emitting means disposed at a reference point, and a laser beam emitted from the laser beam emitting means. By comprising a plurality of half mirrors disposed on the object to be measured so as to be inclined with respect to the optical path along the optical path, and a solid-state imaging means disposed in the optical path of the laser beam reflected from each half mirror, Strain measurements can be easily and accurately performed at any location.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

FIG. 1 is a diagram showing an embodiment in which the present invention is applied to strain measurement and vibration analysis of a bridge deck.

In the figure, reference numeral 1 indicates the bridge deck supported by the bridge station 2...

Then, a laser beam oscillator 3 is placed at a measurement reference point at a predetermined position of the geta 2, and the laser beam oscillator 3 is placed along the optical path 4 of the laser beam emitted from the laser beam oscillator 3 at an angle of, for example, 45 degrees with respect to the optical path 4. A plurality of half mirrors 5 are arranged on the bridge deck 1 which is the object to be measured, and an optical path 6 of the laser beam reflected from each half mirror 5 is further set.
A two-dimensional CCD camera 7 is placed at each of the two.

As a result, distortion occurs in this bridge deck 1, and for example, the second
As shown in the figure, if the position of the bridge deck 1 is displaced from the solid line in the figure to the position indicated by the broken line in the figure, the positions of the half mirror 5 and the CCD camera 7 placed at each position will also be changed from the solid line in the figure to the position indicated by the broken line in the figure. Displaced to the position indicated by the dashed line. On the other hand, since the optical path 4 of the laser beam is stationary, the position of the optical path 6 of the laser beam reflected from the half mirror 5 where the CCD camera 7 is irradiated varies from the position (a) to the position (b) shown in FIG. Displaced to the position shown in . However, the amount of distortion is measured by detecting the displacement of the optical path 6 of the laser beam with the CCD camera 7 and analyzing the data. In addition, the displacement at each position can be measured in time series, and vibration analysis can be performed using the data obtained by conventional methods.

In addition, although the example mentioned above showed what the bridge deck slab 1 displaced up and down, for example, even when this bridge deck slab 1 is displaced from side to side, it can measure similarly. In this case, the position of the optical path 6 of the laser beam reflected from the half mirror 5 where the CCD camera 7 is irradiated is displaced in the directions (C) to (D) shown in FIG.

In addition, a set of two-dimensional CCD cameras 7 are placed at predetermined positions of Hashigami Station 2, which is the object to be measured, and a laser beam oscillator 3
is placed on the ground as a measurement reference point, and by irradiating the CCD camera 7 with a laser beam emitted from the laser beam oscillator 3, the strain at Hashigami Station 2 can be measured. In addition, by measuring this value in time series, correction can be made to set the measurement reference point in the above-mentioned vibration analysis of the bridge deck 1 to the ground.

Next, another embodiment to which the present invention is applied will be described.

FIG. 4 shows the application of the present invention to strain measurement in a force loading system, and the reference numeral 8 in the figure is a structure to which strain is applied by the force loading system 9. It has become. Then, a laser beam oscillator 3 is arranged at a measurement reference point at a predetermined position on the ground, and a plurality of half mirrors 5 and a two-dimensional CCD
By arranging the camera 7 on the structure 8 that is the object to be measured in the same manner as in the above-mentioned embodiment, the strain can be measured in the same manner as in the above-mentioned embodiment.

Figure 5 shows the application of the present invention to strain measurement in horizontal and vertical poling holes for earthquake prediction. By arranging a laser beam oscillator 3 in the hole, and arranging a plurality of half mirrors 5 and a two-dimensional CCD camera 7 at predetermined positions in the hole of the polling 10, which is the object to be measured, this can be achieved in the same manner as in the above embodiment. Strain can be measured.

FIG. 6 shows the application of the present invention to the measurement of strain caused by metal fatigue in a tow truck. In this case as well, the laser beam oscillator 3 is placed at the measurement reference point at the base of the tow truck, indicated by reference numeral 11 in the figure. In addition, by arranging a plurality of half mirrors 5 and a two-dimensional CCD camera 7 at predetermined positions of the tow truck 11, which is the object to be measured, the strain can be measured in the same manner as in the embodiment described above.

[Effects of the Invention] As explained above, according to the strain measuring device of the present invention,
Strain can be easily and accurately measured at any location by simply arranging a half mirror and a solid-state imaging means on the object to be measured and a laser beam oscillator at a reference point.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of one embodiment of the present invention, and FIG.
6 through 6 are explanatory diagrams of other embodiments of the present invention. 3... Laser beam oscillator 5...
... Half mirror 7 ... CCD camera applicant Harada Electronics Co., Ltd. applicant
Kiyoshi Suyama Agent Patent Attorney Suyama Sa - Figure 3

Claims (1)

[Claims] (1) A laser beam emitting means disposed at a reference point, a plurality of half mirrors disposed on the object to be measured along the optical path of the laser beam emitted from the laser beam emitting means, and being inclined with respect to this optical path; A strain measuring device comprising: solid-state imaging means disposed in the optical path of the laser beam reflected from the half mirror.