JP6150014B2 - Strain measuring method and strain measuring system - Google Patents

Description

  The present invention relates to a strain measuring method and a strain measuring system.

  In Patent Document 1, as a method of detecting a crack in a longitudinal welded portion of a high-temperature pipe for a thermal power plant, the amount of strain fluctuation that varies with the pressure inside the tube in the vicinity of the longitudinal welded portion and on the same circumference as the portion concerned. Is measured with a strain gauge, the difference between the strain fluctuations at these two locations is obtained, and a plurality of sample tubes having the same shape as the high-temperature pipe to be inspected are prepared. Form cracks, measure the difference in strain variation in the pipe base near the longitudinal weld and the same circumference as the high temperature pipe to be inspected, and numerically analyze the presence or absence of cracks and crack depth. Measure the presence and depth of cracks in the longitudinal welds of high-temperature pipes by calculating the length and comparing the amount of strain fluctuation in high-temperature pipes with the relationship between the crack depth obtained by numerical analysis and the difference in strain fluctuations about It has been described.

  In Patent Document 2, an optical strain gauge that is attached to a measurement object, can reflect light, and includes a plurality of reflection surfaces whose angles change with strain deformation of the measurement object, and a plurality of reflection surfaces Angle change of multiple reflective surfaces by irradiating light, detecting reflected light reflected from multiple reflective surfaces, and comparing reflected light reflected from multiple reflective surfaces before and after strain deformation of the measurement object An optical strain measurement device is disclosed that includes an angle measurement unit that measures the distortion and a strain calculation unit that calculates the strain of the measurement object from the angle change measured by the angle measurement unit.

JP 2002-286444 A JP 2011-163896 A

  As disclosed in Patent Document 1, measurement of cracks in piping for thermal power plants is performed using a strain gauge that utilizes a change in electrical resistance value according to the strain amount of metal or semiconductor. However, since piping such as boiler piping in a thermal power plant has a high temperature of 600 ° C. or higher, there is a problem that the output of the strain cage is not stable particularly during operation of the actual machine and sufficient measurement accuracy cannot be obtained.

  The present invention has been made in view of the above problems, and provides a strain measuring method and a strain measuring system capable of accurately measuring the strain generated on the surface of the object to be measured with a simple configuration. It is aimed.

One aspect of the present invention for achieving the above object is a method for measuring strain generated on the surface of the object to be measured, wherein the structure is different from the object to be measured that is separated from the surface of the object to be measured by a predetermined distance. The first laser displacement meter and the second laser displacement meter are fixed , and the first reflector and the second reflector are arranged in the vicinity of the measurement target portion on the surface of the object to be measured, and the reflection surfaces of both of the structures are the same. The first laser displacement meter is arranged adjacent to the direction, and the reflection surface of the first reflector is in accordance with the amount of displacement of the first reflector due to the strain generated on the surface of the object to be measured. The second laser displacement meter has a shape in which the distance between the second reflector and the second reflector is changed even if the first reflector is displaced due to the distortion generated on the surface of the object to be measured. The distance between and the first laser displacement meter is directed from the light emitting portion toward the first reflector. The amount of change in the first path that is the path of the first laser light when the first laser light emitted in this way is reflected by the reflecting surface of the first reflector and is incident on the light receiving portion of the first laser displacement meter. Is measured by the first laser displacement meter, and the second laser light emitted from the light emitting portion of the second laser displacement meter toward the second reflector is reflected by the reflecting surface of the second reflector, and the first laser displacement meter reflects the second laser beam. The amount of change in the second path, which is the path of the second laser light, when incident on the light receiving portion of the two-laser displacement meter is measured by the second laser displacement meter, and the amount of change in the first path and the second Based on the difference from the amount of change in the path, the strain generated in the measurement target part is obtained.

  According to the present invention, the distortion generated on the surface of the object to be measured can be accurately measured with a simple configuration using a laser displacement meter and a reflector. In addition, since the laser displacement meter (including the light emitting unit and the light receiving unit) is provided at a location away from the object to be measured, it is not affected by heat even when the object to be measured becomes high temperature, and laser displacement is performed at room temperature. The strain can be measured with high accuracy. In addition, a structure using a displacement measured based on a laser beam reflected by a reflector having a slope-shaped reflecting surface and a displacement measured based on a laser beam reflected by a reflector having a planar reflecting surface is used. Since the error caused by the change in the distance between the object and the object to be measured is corrected, the strain can be measured with high accuracy. In addition, since the laser displacement meter (including the light emitting unit and the light receiving unit) can be installed in any structure in the building, the installation location is highly flexible, and the present invention can be applied to various environments.

Another aspect of the present invention is the measurement method described above, wherein a third laser displacement meter and a fourth laser displacement meter are attached to a structure different from the measurement object that is separated from the surface of the measurement object by a predetermined distance. Fixing, in the vicinity of the measurement target part of the surface of the object to be measured, the third reflector and the fourth reflector are both arranged adjacent to each other with the reflecting surface facing the direction of the structure, The set of the first reflector and the second reflector and the set of the third reflector and the fourth reflector are arranged so as to sandwich the measurement target portion therebetween, and the reflection surface of the third reflector Exhibits a shape in which the distance from the third laser displacement meter changes according to the amount of displacement of the third reflector due to the strain generated on the surface of the object to be measured. Even if the fourth reflector is displaced due to the strain generated on the surface of the object to be measured, the reflecting surface is not in contact with the fourth laser displacement meter. The third laser displacement has a shape in which the distance does not change, and the third laser light emitted from the light emitting portion of the third laser displacement meter toward the third reflector is reflected by the reflecting surface of the third reflector. The amount of change in the third path, which is the path of the third laser light when entering the light receiving part of the meter, is measured by the third laser displacement meter, and the fourth reflection from the light emitting part of the fourth laser displacement meter. A fourth laser beam that is a path of the fourth laser beam when the fourth laser beam emitted toward the body is reflected by the reflecting surface of the fourth reflector and is incident on the light receiving portion of the fourth laser displacement meter. Is measured by the fourth laser displacement meter, and the value obtained by subtracting the amount of change of the second route from the amount of change of the first route, and the amount of change of the fourth route from the amount of change of the third route. By subtracting And determining the distortion caused to the target site.

  According to the present invention, the displacement measured by the pair of the first reflector and the second reflector, and the displacement measured by the pair of the third reflector and the fourth reflector, which are arranged with the measurement target part interposed therebetween. Based on the amount, the absolute amount of strain generated on the surface of the object to be measured can be obtained with high accuracy.

  Another aspect of the present invention is the measurement method described above, wherein the distance between the reflection surface of the first reflector and the second laser displacement meter changes linearly along the direction in which the distortion occurs. The reflecting surface of the second reflector is a planar shape parallel to the direction in which the distortion occurs, and the reflecting surface of the third reflector is along the direction in which the distortion occurs. The distance between the third laser displacement meter and the third laser displacement meter has a slope shape that changes linearly, and the reflection surface of the fourth reflector has a planar shape parallel to the direction in which the distortion occurs.

  The reflecting surface of the first reflector and the reflecting surface of the second reflector are made of, for example, a metal plate or a ceramic plate.

  The reflecting surface of the first reflector and the reflecting surface of the second reflector have, for example, a structure in which sapphire glass is coated on the surface of a metal film that has been mirror-finished.

  Moreover, the reflective surface of the said 1st reflector thru | or a 4th reflector is comprised by the metal plate or the ceramic plate, for example.

  The reflective surfaces of the first to fourth reflectors have a structure in which sapphire glass is coated on the surface of a mirror-finished metal film.

  The object to be measured is, for example, a high-temperature pipe of a thermal power plant, and the structure is a part of a building in which the thermal power plant is accommodated.

  In addition, the subject which this application discloses, and its solution method are clarified by the column of the form for inventing, and drawing.

  According to the present invention, distortion generated on the surface of the object to be measured can be accurately measured with a simple configuration.

1 is a diagram illustrating a schematic configuration of a strain measurement system 1. FIG. It is the perspective view which expanded and drew the 1st reflector 12 and the 2nd reflector 22. FIG. It is the perspective view which expanded and drew the 3rd reflector 32 and the 4th reflector 42. FIG. 2 is a configuration diagram of a laser displacement meter 100 shown as an example of a first laser displacement meter 10, a second laser displacement meter 20, and a third laser displacement meter 30. FIG. It is a figure explaining the measurement principle of a laser displacement meter. It is a figure explaining the measuring method of distortion.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a strain measurement system 1 described as an embodiment. The strain measuring system 1 measures the strain generated on the surface of the object 2 to be measured, which becomes a high temperature at the time of measurement, such as a steel boiler reburning steam pipe (hereinafter also referred to as high temperature piping) of a thermal power plant. In a thermal power plant, for the purpose of extending the life of the power generation facility, strain generated on the pipe surface due to creep damage or the like is measured at any time during operation of the power generation facility.

  As shown in the figure, the DUT 2 has a crack 3 that has occurred in the past and a weld 4 that is formed when the crack 3 is repaired. Although the surface of the object to be measured 2 is covered with the heat insulating material 5, the heat insulating material 5 is removed and the surface of the object to be measured 2 is exposed in a partial region in the vicinity of the welded portion 4 which is a strain measurement target portion. I am letting.

  A set of a first reflector 12 and a second reflector 22 (hereinafter referred to as a first reflection) on one side of the welded portion 4 so as to sandwich the welded portion 4 on the surface of the workpiece 2 near the welded portion 4. (Also referred to as a body set)), a set of the third reflector 32 and the fourth reflector 42 (hereinafter also referred to as a second reflector set) is disposed on the other side of the welded portion 4. Each of the first reflector 12 to the fourth reflector 42 has a reflective surface that faces the direction of the building structure 6 (roof, beam, wall, etc.) in which the thermal power plant is accommodated, for example. .

  The light emitting unit 11 and the light receiving unit 13 of the first laser displacement meter 10 and the light emission of the second laser displacement meter 20 are located on the surface of the DUT 2 at a position away from the first reflector set by a predetermined distance in the + z direction. The unit 21 and the light receiving unit 23 are provided. In addition, the light emitting unit 31 and the light receiving unit 33 of the third laser displacement meter 30 and the fourth laser displacement meter 40 are located at a position on the surface of the DUT 2 that is a predetermined distance away from the second reflector set in the + z direction. A light emitting unit 41 and a light receiving unit 43 are provided. The first to fourth laser displacement meters 10, 20, 30 and 40 are all fixed at predetermined positions of the structure 6.

  The reflection surface 12a of the first reflector 12 has a shape in which the distance from the first laser displacement meter 10 changes according to the amount of displacement of the first reflector 12 due to the strain generated on the surface of the DUT 2. On the other hand, the reflection surface 22a of the second reflector 22 has a distance from the second laser displacement meter 20 even if the second reflector 22 is displaced due to the strain generated on the surface of the object 2 to be measured. It has a shape that does not change.

  FIG. 2 is an enlarged perspective view of the first reflector 12 and the second reflector 22 provided on the surface of the part to be measured 2 while maintaining the respective arrangement states. As shown in the figure, the upper surface (reflecting surface 12a) of the first reflector 12 is linearly formed at a predetermined angle along the direction in which the surface of the DUT 2 is distorted (the direction along the y-axis). The slope shape is inclined, and the upper surface (reflecting surface 22a) of the second reflector 22 is a planar shape parallel to the direction in which the surface of the DUT 2 is distorted. As shown in the figure, in this example, the first reflector 12 has a triangular prism shape, and the second reflector 22 has a rectangular parallelepiped shape. In this example, it is assumed that the angle formed by the upper surface (reflection surface 12a) of the first reflector 12 and the upper surface (reflection surface 22a) of the second reflector 22 is α.

  In this example, the first reflector 12 is configured as a separate block from the object 2 to be measured. However, the first reflection 12 is formed by forming a reflecting surface with the surface of the object 2 to be inclined. The body 12 may be configured as a part of the DUT 2. Similarly, in this example, the second reflector 22 is configured as a separate block from the DUT 2, but the second reflector 22 is formed by using the surface of the DUT 2 as a reflecting surface. You may comprise as a part of to-be-measured object 2. FIG.

  The reflection surface 32 a of the third reflector 32 has a shape in which the distance from the third laser displacement meter 30 changes according to the amount of displacement of the third reflector 32 due to the strain generated on the surface of the DUT 2. On the other hand, the reflection surface 42a of the fourth reflector 42 has a distance from the fourth laser displacement meter 40 even if the fourth reflector 42 is displaced due to the strain generated on the surface of the object 2 to be measured. It has a shape that does not change.

  FIG. 3 is an enlarged perspective view of the third reflector 32 and the fourth reflector 42 provided on the surface of the part 2 to be measured while maintaining the respective arrangement states. As shown in the figure, the upper surface (reflecting surface 32a) of the third reflector 32 is linearly formed at a predetermined angle along the direction in which the surface of the DUT 2 is distorted (the direction along the y-axis). The upper surface (reflective surface 42a) of the fourth reflector 42 has a planar shape parallel to the direction in which the surface of the DUT 2 is distorted. As shown in the figure, in this example, the third reflector 32 has a triangular prism shape, and the fourth reflector 42 has a rectangular parallelepiped shape. In this example, it is assumed that the angle formed by the upper surface (reflecting surface 32a) of the third reflector 32 and the upper surface (reflecting surface 42a) of the fourth reflector 42 is α.

  In this example, the third reflector 32 is configured as a separate block from the object to be measured 2, but by forming a reflective surface with the surface of the object to be measured 2 as a slope shape, the third reflection is formed. The body 32 may be configured as a part of the DUT 2. Similarly, in this example, the fourth reflector 42 is configured as a separate block from the device under test 2, but the surface of the device under test 2 is used as a reflecting surface, so that the fourth reflector 42 is formed. You may comprise as a part of to-be-measured object 2. FIG.

  The first laser displacement meter 10 and the first reflector 12 constitute a first measurement system. In the first measurement system, the first laser displacement meter 10 emits laser light (hereinafter referred to as first laser light) emitted from the light emitting unit 11 of the first laser displacement meter 10 toward the first reflector 12. Changes in the path of the first laser beam (hereinafter referred to as the first path) when the light is reflected by the upper surface (reflection surface 12a) of the first reflector 12 and is incident on the light receiving unit 13 of the first laser displacement meter 10. Measure the amount. The first laser displacement meter 10 measures the amount of change in the first path using a diffuse reflection component generated by the first laser beam being reflected by the upper surface (reflection surface 12a) of the first reflector 12. .

  The second laser displacement meter 20 and the second reflector 22 constitute a second measurement system. In the second measurement system, the second laser displacement meter 20 emits laser light (hereinafter referred to as second laser light) emitted from the light emitting unit 21 of the second laser displacement meter 20 toward the second reflector 22. Changes in the path of the second laser light (hereinafter referred to as the second path) when the light is reflected by the upper surface (reflection surface 22a) of the second reflector 22 and is incident on the light receiving unit 23 of the second laser displacement meter 20. Measure the amount. The second laser displacement meter 20 changes the first path by using a regular reflection component or a diffuse reflection component generated when the second laser beam is reflected by the upper surface (reflection surface 22a) of the second reflector 22. Measure the amount.

  The third laser displacement meter 30 and the third reflector 32 constitute a third measurement system. In the third measurement system, the third laser displacement meter 30 emits laser light (hereinafter referred to as third laser light) emitted from the light emitting unit 31 of the third laser displacement meter 30 toward the third reflector 32. Changes in the path of the third laser light (hereinafter referred to as the third path) when the light is reflected by the upper surface (reflecting surface 32a) of the third reflector 32 and is incident on the light receiving unit 33 of the third laser displacement meter 30. Measure the amount. The third laser displacement meter 30 measures the amount of change in the third path by using a diffuse reflection component that is generated when the third laser light is reflected by the upper surface (reflection surface 32a) of the third reflector 32. .

  The fourth laser displacement meter 40 and the fourth reflector 42 constitute a fourth measurement system. In the fourth measurement system, the fourth laser displacement meter 40 emits laser light (hereinafter referred to as fourth laser light) emitted from the light emitting portion 41 of the fourth laser displacement meter 40 toward the fourth reflector 42. Changes in the path of the fourth laser light (hereinafter referred to as the fourth path) when the light is reflected by the upper surface (reflection surface 42a) of the fourth reflector 42 and is incident on the light receiving unit 43 of the fourth laser displacement meter 40. Measure the amount. The fourth laser displacement meter 40 changes the first path by using a regular reflection component or a diffuse reflection component that is generated when the fourth laser beam is reflected by the upper surface (reflection surface 42a) of the fourth reflector 42. Measure the amount.

  Each of the first to fourth reflectors 12, 22, 32, and 42 has a property that the side facing the object to be measured 2 has stable properties (not deformed or melted) even at high temperatures (about 600 ° C.). It is composed of materials. In addition, the reflection surfaces 12a, 22a, 32a, and 42a of the first reflector 12, the second reflector 22, the third reflector 32, and the fourth reflector 42 are all made of materials that are difficult to attach water droplets or the like. It is configured using. These reflecting surfaces 12a, 22a, 32a, 42a are made of, for example, a metal plate (SUS plate, platinum plate, etc.), a ceramic plate, or the like. As the laser displacement meter (first to fourth laser displacement meters 10, 20, 30, 40), for example, a time difference type laser displacement meter or a part of a highly accurate triangulation type laser displacement meter is used. The reflective surfaces 12a, 22a, 32a, and 42a of the first reflector 12, the second reflector 22, the third reflector 32, and the fourth reflector 42 are mirror-finished metal films (platinum film or the like). The surface of the metal film may be coated with sapphire glass or the like to prevent corrosion or contamination.

  FIG. 4 shows an example of a laser displacement meter (first to fourth laser displacement meters 10, 20, 30, 40) (hereinafter referred to as a laser displacement meter 100). As shown in the figure, the laser displacement meter 100 includes a processor 111, an input device 112, an output device 113, a laser drive circuit 114, a light emitting element 115, a light receiving element 116, a displacement detection circuit 117, and an optical element 118.

  The processor 111 is configured using, for example, a microcomputer, an MPU (Micro Processing Unit), a CPU (Central Processing Unit), and the like, and inputs information detected by the overall control of the laser displacement meter and the displacement detection circuit 117. Various arithmetic processes are performed. The input device 112 is a user interface (such as operation buttons and a touch panel) that accepts various input operations on the laser displacement meter 100. The output device 113 is a user interface (such as a liquid crystal panel) that outputs various measurement results.

  The laser drive circuit 114 includes a circuit (such as an ACC (Automatic Current Control) circuit or an APC (Automatic Power Control) circuit) that generates a drive current for the light emitting element 115.

  The light emitting element 115 is a constituent element of the above-described light emitting units 11, 21, 31, 41, and is configured using, for example, a semiconductor laser element (laser diode or the like). The light receiving element 116 is a component of the light receiving units 13, 23, 33, and 43 described above, and is configured using a PSD (Position Sensitive Detector), a CMOS (Complementary Metal Oxide Semi-conductor), or the like.

  The displacement detection circuit 117 includes an amplification circuit for a signal output from the light receiving device 116 and outputs information indicating the displacement of the DUT 2. The optical element 118 includes, for example, a light projecting lens that condenses the laser light emitted from the light emitting element 115 and a light receiving lens that condenses the laser light incident on the light receiving element 116.

  Next, the measurement principle (triangular distance measuring method) of the laser displacement meter 100 will be described with reference to FIG. In the figure, the laser light emitted from the light emitting element 115 is condensed by the light projecting lens 118 and irradiated to the object 2 to be measured. Laser light (regular reflection component or diffuse reflection component) reflected from the DUT 2 is collected by the light receiving lens 118 and forms a spot on the light receiving surface of the light receiving element 116. Since the spot moves when the DUT 2 moves, information indicating the displacement of the DUT 2 can be obtained by detecting the position of the spot. The above measurement principle is only an example, and the laser displacement meter 100 may be based on another measurement principle.

  Next, with reference to FIG. 6, a specific method for measuring strain generated in the measurement target portion, which is performed by the strain measurement system 1 having the above configuration, will be described.

  The measurement of the strain generated on the surface of the DUT 2 is performed by executing measurements by the first to fourth measurement systems at any time and performing the calculation described below based on the measurement results.

  First, the first path described above is emitted from the light emitting portion 11 of the first laser displacement meter 10, enters the first reflector 12, is reflected by the first reflector 12, and is received by the light receiving portion 13 of the first laser displacement meter 10. Is the path (= d1) of the first laser light incident on the.

  The second path described above is emitted from the light emitting unit 21 of the second laser displacement meter 20, enters the second reflector 22, is reflected by the second reflector 22, and is received by the light receiving unit 23 of the second laser displacement meter 20. This is the path (= d2) of the second laser light incident on.

  The third path described above is emitted from the light emitting unit 31 of the third laser displacement meter 30, enters the third reflector 32, is reflected by the third reflector 32, and is the light receiving unit 33 of the third laser displacement meter 30. Is the path of the third laser light incident on (= d3).

  Further, the above-described fourth path is emitted from the light emitting portion 41 of the fourth laser displacement meter 40, enters the fourth reflector 42, is reflected by the fourth reflector 42, and is the light receiving portion 43 of the fourth laser displacement meter 40. This is the path (= d4) of the fourth laser light incident on.

  Here, when distortion occurs in the DUT 2, the first reflector group and the second reflector group are displaced along the y-axis direction. In this case, the upper surface (reflection surface 12a) of the first reflector 12 is a straight line at a predetermined angle α with respect to the direction along the direction in which the surface of the DUT 2 is distorted (the direction along the y axis). Therefore, when the first reflector set is displaced in the y-axis direction, the path (= d1) of the first laser light changes. On the other hand, since the upper surface (reflecting surface 22a) of the second reflector 22 has a planar shape parallel to the direction in which the surface of the DUT 2 is distorted, the first reflector set is displaced in the y-axis direction. The path of the second laser beam (= d2) does not change. Therefore, the displacement amount in the y-axis direction of the first reflector group can be obtained from the following equation.

Amount of displacement of the first reflector set in the y-axis direction × tan α
= ((Displacement amount of first laser beam path (= Δd1)
-Amount of displacement of the path of the second laser beam (= Δd2))
... Formula 1

  In Equation 1, the displacement of the path of the second laser beam (= Δd2) is subtracted from the displacement of the path of the first laser beam (= Δd1). Even when the distance changes for some reason such as a change in temperature, the displacement amount of the first reflector set in the y-axis direction can be obtained with high accuracy.

  On the other hand, the upper surface (reflecting surface 32a) of the third reflector 32 is linear at a predetermined angle α with respect to the direction along the direction in which the surface of the DUT 2 is distorted (the direction along the y-axis). Therefore, the path (= d3) of the third laser light changes with the displacement of the second reflector set in the y-axis direction. On the other hand, since the upper surface (reflecting surface 42a) of the fourth reflector 42 has a planar shape parallel to the direction in which the surface of the DUT 2 is distorted, the second reflector set is displaced in the y-axis direction. The path of the fourth laser beam (= d4) does not change. Therefore, the amount of displacement in the y-axis direction of the second reflector set can be obtained from the following equation.

Amount of displacement of the second reflector set in the y-axis direction × tan α
= (Displacement amount of path of third laser beam (= Δd3)
-Amount of displacement of the path of the fourth laser beam (= Δd4))
... Formula 2

  In Equation 2, the displacement amount (= Δd4) of the path of the fourth laser beam is subtracted from the displacement amount (= Δd3) of the path of the third laser beam. Even when the distance changes for some reason such as a change in temperature, the amount of displacement of the second reflector set in the y-axis direction can be obtained with high accuracy.

  The absolute amount of strain generated on the surface of the DUT 2 is the sum of the displacement amount of the first reflector set in the y-axis direction and the displacement amount of the second reflector set in the y-axis direction. It can be obtained from the following equation using Equation 2.

Absolute amount of strain x tan α
= (Displacement amount of first laser beam path (= Δd1))
-Amount of displacement of the path of the second laser beam (= Δd2))
+ (Path displacement of the third laser beam (= Δd3)
-Amount of displacement of the path of the fourth laser beam (= Δd4))
... Formula 3

  As described above, according to the strain measurement system 1 of the present embodiment, the strain generated on the surface of the object to be measured can be accurately measured with a simple configuration using the laser displacement meter and the reflector. . In addition, a laser displacement meter (including the light emitting unit and light receiving unit) is provided at a location away from the object to be measured, so even if the object to be measured is at a high temperature, it is not affected by heat, and laser displacement is performed at room temperature. The strain can be measured with high accuracy. In addition, a structure using a displacement measured based on a laser beam reflected by a reflector having a slope-shaped reflecting surface and a displacement measured based on a laser beam reflected by a reflector having a planar reflecting surface is used. Since the error caused by the change in the distance between the object and the object to be measured is corrected, the strain can be measured with high accuracy. Further, since the laser displacement meter (including the light emitting unit and the light receiving unit) can be installed in any structure in the building, the installation location is highly flexible, and the strain measurement system 1 of the present embodiment has various environments. Can be applied to.

  By the way, the above description is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be changed and improved without departing from the spirit thereof, and the present invention includes equivalents thereof. For example, in the strain measurement system 1 described above, a laser displacement meter is used to measure the path change, but the path change may be measured using a laser distance meter.

DESCRIPTION OF SYMBOLS 1 Strain measuring system, 2 to-be-measured object, 3 crack, 4 welding part, 5 heat insulating material, 6 structure, 10 1st laser displacement meter, 11 light emission part, 12 1st reflector, 13 light-receiving part, 20 2nd laser Displacement meter, 21 Light emitting part, 22 Second reflector, 23 Light receiving part, 30 Third laser displacement meter, 31 Light emitting part, 32 Third reflector, 33 Light receiving part, 40 Fourth laser displacement meter, 41 Light emitting part, 42 4th reflector, 43 light-receiving part, 100 laser displacement meter

Claims (11)

A method for measuring strain generated on the surface of an object to be measured,
Fixing the first laser displacement meter and the second laser displacement meter to a structure different from the object to be measured that is separated from the surface of the object to be measured by a predetermined distance;
In the vicinity of the measurement target site on the surface of the object to be measured, both the first reflector and the second reflector are arranged adjacent to each other with the reflecting surface facing the direction of the structure,
The reflecting surface of the first reflector has a shape in which the distance from the first laser displacement meter changes according to the amount of displacement of the first reflector due to the strain generated on the surface of the object to be measured. Present,
The reflective surface of the second reflector exhibits a shape in which the distance from the second laser displacement meter does not change even when the first reflector is displaced due to strain generated on the surface of the object to be measured.
The first laser light emitted from the light emitting portion of the first laser displacement meter toward the first reflector is reflected by the reflecting surface of the first reflector and is incident on the light receiving portion of the first laser displacement meter. A change amount of the first path which is a path of the first laser light in a case is measured by the first laser displacement meter,
The second laser light emitted from the light emitting portion of the second laser displacement meter toward the second reflector is reflected by the reflecting surface of the second reflector and is incident on the light receiving portion of the second laser displacement meter. A change amount of a second path which is a path of the second laser light in a case is measured by the second laser displacement meter,
A strain measurement method for obtaining strain generated in the measurement target part based on a difference between the change amount of the first route and the change amount of the second route. The strain measurement method according to claim 1,
Fixing the third laser displacement meter and the fourth laser displacement meter to a structure different from the object to be measured that is separated from the surface of the object to be measured by a predetermined distance;
In the vicinity of the measurement target site on the surface of the object to be measured, the third reflector and the fourth reflector are both arranged adjacent to each other with the reflecting surface directed toward the structure,
The set of the first reflector and the second reflector and the set of the third reflector and the fourth reflector are arranged so that the measurement target part is sandwiched therebetween,
The reflective surface of the third reflector has a shape in which the distance from the third laser displacement meter changes according to the amount of displacement of the third reflector due to the strain generated on the surface of the object to be measured. Present,
The reflective surface of the fourth reflector exhibits a shape in which the distance from the fourth laser displacement meter does not change even when the fourth reflector is displaced due to distortion generated on the surface of the object to be measured,
The third laser light emitted from the light emitting portion of the third laser displacement meter toward the third reflector is reflected by the reflecting surface of the third reflector and is incident on the light receiving portion of the third laser displacement meter. A change amount of a third path which is a path of the third laser light in a case is measured by the third laser displacement meter,
The fourth laser light emitted from the light emitting portion of the fourth laser displacement meter toward the fourth reflector is reflected by the reflecting surface of the fourth reflector and is incident on the light receiving portion of the fourth laser displacement meter. The amount of change in the fourth path, which is the path of the fourth laser light in the case, is measured by the fourth laser displacement meter,
By calculating the sum of the value obtained by subtracting the change amount of the second route from the change amount of the first route and the value obtained by subtracting the change amount of the fourth route from the change amount of the third route. Strain measurement method to obtain the strain generated in the target part. The strain measuring method according to claim 2,
The reflection surface of the first reflector has a slope shape that is inclined so that a distance between the second laser displacement meter and the second laser displacement meter changes linearly along a direction in which the distortion occurs.
The reflection surface of the second reflector has a planar shape parallel to the direction in which the distortion occurs,
The reflective surface of the third reflector has a slope shape in which the distance between the third laser displacement meter and the third laser displacement meter changes linearly along the direction in which the distortion occurs.
The reflection surface of the fourth reflector has a planar shape parallel to the direction in which the distortion occurs. A measurement system for strain generated on the surface of an object to be measured,
The device under test a predetermined distance away from the surface of the object Ru fixed to different structures, a first laser displacement gauge and a second laser displacement gauge,
A first reflector and a second reflector, both of which are arranged adjacent to the measurement target portion of the surface of the object to be measured, with the reflecting surfaces thereof facing toward the structure,
With
The reflecting surface of the first reflector has a shape in which the distance from the first laser displacement meter changes according to the amount of displacement of the first reflector due to the strain generated on the surface of the object to be measured. Present,
The reflective surface of the second reflector exhibits a shape in which the distance from the second laser displacement meter does not change even when the first reflector is displaced due to strain generated on the surface of the object to be measured.
The first laser displacement meter reflects the first laser light emitted from the light emitting portion of the first laser displacement meter toward the first reflector by the reflection surface of the first reflector, thereby causing the first laser displacement meter to Measuring the amount of change of the first path, which is the path of the first laser light, when entering the light receiving portion of the meter,
The second laser displacement meter reflects the second laser light emitted from the light emitting portion of the second laser displacement meter toward the second reflector by the reflection surface of the second reflector, thereby causing the second laser displacement meter. A strain measurement system for measuring a change amount of a second path, which is a path of the second laser light, when being incident on a light receiving portion of a meter. The strain measurement system according to claim 4,
Wherein Ru is secured to a different structure from that of the object to be measured a predetermined distance away from the surface of the object to be measured, and a third laser displacement meter and fourth laser displacement meter,
A third reflector and a fourth reflector, which are arranged adjacent to each other on the surface of the object to be measured, with their reflecting surfaces facing the direction of the structure,
Further comprising
The set of the first reflector and the second reflector and the set of the third reflector and the fourth reflector are arranged so as to sandwich the measurement target portion therebetween,
The reflective surface of the third reflector has a shape in which the distance from the third laser displacement meter changes according to the amount of displacement of the third reflector due to the strain generated on the surface of the object to be measured. Present,
The reflective surface of the fourth reflector exhibits a shape in which the distance from the fourth laser displacement meter does not change even when the fourth reflector is displaced due to distortion generated on the surface of the object to be measured,
The third laser displacement meter reflects the third laser light emitted from the light emitting portion of the third laser displacement meter toward the third reflector by the reflecting surface of the third reflector, thereby causing the third laser displacement meter to Measuring the amount of change of the third path, which is the path of the third laser light, when entering the light receiving portion of the meter,
The fourth laser displacement meter reflects the fourth laser light emitted from the light emitting portion of the fourth laser displacement meter toward the fourth reflector by the reflection surface of the fourth reflector, thereby causing the fourth laser displacement meter. Measure the amount of change of the fourth path, which is the path of the fourth laser light when entering the light receiving portion of the meter,
Strain measurement system. The strain measurement system according to claim 5,
The reflection surface of the first reflector has a slope shape that is inclined so that a distance between the second laser displacement meter and the second laser displacement meter changes linearly along a direction in which the distortion occurs.
The reflection surface of the second reflector has a planar shape parallel to the direction in which the distortion occurs,
The reflective surface of the third reflector has a slope shape in which the distance between the third laser displacement meter and the third laser displacement meter changes linearly along the direction in which the distortion occurs.
The reflection surface of the fourth reflector has a planar shape parallel to the direction in which the distortion occurs. The strain measurement system according to claim 4,
The reflective surface of the first reflector and the reflective surface of the second reflector are made of a metal plate or a ceramic plate.
Strain measurement system. The strain measurement system according to claim 4,
The reflective surface of the first reflector and the reflective surface of the second reflector have a structure in which a sapphire glass is coated on the surface of a mirror-finished metal film,
Strain measurement system. The strain measurement system according to claim 5,
The reflection surface of the first reflector to the fourth reflector is composed of a metal plate or a ceramic plate.
Strain measurement system. The strain measurement system according to claim 5,
The reflective surfaces of the first reflector to the fourth reflector have a structure in which sapphire glass is coated on the surface of a mirror-finished metal film,
Strain measurement system. The strain measurement system according to any one of claims 4 to 10,
The measurement object is a high-temperature pipe of a thermal power plant, and the structure is a part of a building in which the thermal power plant is accommodated.

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