JP6842084B2 - Portable 3-axis stress measuring device - Google Patents

Description

The present invention relates to a portable triaxial stress measuring device.

Conventionally, in a device that measures local stress on the crystal surface such as residual stress and concentrated stress by using X-ray diffraction, the sin ² Ψ method as a simple method or the back surface from a single obliquely incident X-ray is used as a method for obtaining the stress. The cosα method using a diffraction ring measured by the reflection method is often used (see, for example, Non-Patent Document 1). However, the sin ² Ψ method and the cos α method can measure only biaxial plane stress in principle, and cannot measure the triaxial stress state including the stress in the depth direction as a tensor.

Therefore, as a device capable of measuring triaxial stress by X-ray diffraction, a device using a 2D method (two dynamic method) has been developed by Bruker AXS (for example, Non-Patent Document 2). Or see 1). In the 2D method, as shown in FIG. 5, the crystal sample 51 was rotated around three axes at various rotation angles of ω, Ψ, and φ, and various combinations of ω, Ψ, and φ were obtained for each rotation angle. The optimum triaxial stress can be obtained by performing multiple regression analysis based on a large number of azimuth strains obtained from the diffraction ring. However, the device using this 2D method is a large stationary device, and since it is necessary to cut out the crystal sample 51 to be measured and place it on the sample stage, it has a long and large structure that is easily affected by processing strain. There are problems such as not being applicable to products and not being able to be incorporated into production lines.

In order to solve these problems, as a method of obtaining triaxial stress without moving the sample to be measured, measurement is performed from 3 or 4 directions using a portable X-ray diffraction device, and the cosα method is used. Based on this, a stress measuring method for obtaining triaxial stress has been developed (see, for example, Patent Document 1 or 2).

The X-ray diffracted ring data detected by the diffracted light receiver such as an imaging plate is irradiated with laser light while rotating the diffracted light receiver, and the laser light irradiation position and reflected light are emitted by the present inventor. An X-ray diffractometer that reads by detecting the intensity and obtains the stress by using the cosα method has been developed (see, for example, Patent Document 3).

Japanese Patent No. 5339253 Japanese Unexamined Patent Publication No. 2014-13203 Japanese Patent No. 5505361

Japan Society for Conservation, ed., "X-ray stress measurement with a two-dimensional detector", Yokendo, October 27, 2015 B. B. He, “Two-Dimensional X-Ray Diffraction”, John Wiley & Sons, 2009

In the stress measuring method described in Patent Document 1 or 2, in order to measure the triaxial stress, it is necessary to change the X-ray irradiation direction and the detection direction of the diffractive ring three or four times, and each time, the X-ray irradiation device or A device for detecting a diffraction ring such as an imaging plate must be accurately moved and installed so that the X-ray irradiation position becomes a predetermined position and the X-ray irradiation angle becomes a predetermined angle. Therefore, there is a problem that it is practically very difficult to perform measurement without lowering the measurement accuracy.

The present invention has been made by paying attention to such a problem, and provides a portable triaxial stress measuring device capable of easily obtaining triaxial stress without moving a measurement target while maintaining measurement accuracy. The purpose is.

In order to achieve the above object, the portable triaxial stress measuring device according to the present invention includes an X-ray irradiation unit that irradiates a measurement target with X-rays and a diffracted light of the X-rays diffracted by the measurement target. The measurement target that irradiates the X-ray with a constant irradiation angle of the X-ray to the surface of the measurement target and a measurement unit having a diffraction light receiving unit provided so as to be able to detect a diffraction ring that is an image of the above. When the measurement unit is rotated relative to the measurement target by the rotation mechanism provided so as to be able to rotate the measurement unit relative to the measurement target and the rotation mechanism. It has a stress acquisition unit for obtaining the triaxial stress of the measurement target from the diffraction ring of the X-ray detected at a plurality of different rotation positions, and the diffraction light receiving unit has the X-ray irradiation unit in the center. An imaging plate for detecting the diffracted ring, which has a through hole for passing X-rays emitted from the through hole and is rotatably provided around the central axis of the through hole, and the diffracted X-ray. It has a front plate arranged on the upstream side of the imaging plate with respect to the traveling direction and provided so as to cover the imaging plate, and a rotation control unit that rotates the imaging plate in accordance with rotation by the rotation mechanism. The front plate has a slit provided so as to extend outward from the central axis of rotation of the imaging plate, and the measuring unit rotates the imaging plate with the rotation control unit while rotating the slit. The diffraction ring is detected by the imaging plate, and the diffraction ring detected by the imaging plate is read from the imaging plate while rotating the imaging plate by the rotation control unit. The stress acquisition unit is characterized in that the triaxial stress of the measurement target is obtained from the data of the diffraction ring read by the measurement unit.

In the portable triaxial stress measuring device according to the present invention, the X-ray diffraction ring can be obtained at a plurality of different rotation positions while rotating the measurement unit relative to the measurement target by the rotation mechanism. At this time, since the measurement unit is rotated in a state where the X-ray irradiation angle with respect to the surface to be measured is constant, it corresponds to the case where ω and Ψ are fixed and only φ is rotated in FIG. The optimum triaxial stress can be obtained from the diffracted rings obtained at a plurality of different rotation positions of φ by performing multiple regression analysis in the same manner as in the 2D method by the stress acquisition unit.

In the portable triaxial stress measuring device according to the present invention, the measurement target may be rotated with respect to the measurement unit by the rotation mechanism, but it is preferable to rotate the measurement unit with respect to the measurement target. When the measuring unit is rotated, the triaxial stress can be obtained without moving the measurement target. In addition, by making it portable, it is possible to perform measurement at a place where a measurement target exists without cutting out a sample from the measurement target. As a result, it is possible to perform measurement even at a joint portion between members, which has been difficult to measure so far. Further, it is possible to eliminate the influence of the stress applied to the sample at the time of cutting out and obtain a more accurate triaxial stress.

Further, in the portable 3-axis stress measuring device according to the present invention, the measuring unit can be easily rotated and moved to each measuring position by the rotating mechanism to perform the measurement, so that the accuracy is lowered due to the deviation of the mounting position of the measuring unit. This can be prevented, and the triaxial stress can be easily obtained while maintaining the measurement accuracy.

In the portable triaxial stress measuring device according to the present invention, the measuring unit includes an X-ray irradiation unit and a diffraction / light receiving unit capable of detecting a diffraction ring from a measurement target by X-rays emitted from the X-ray irradiation unit. Anything may be used as long as it is possessed, and a commercially available X-ray stress measuring device or the like may be used.

In the portable triaxial stress measuring device according to the present invention, it is preferable that the X-ray irradiation unit is configured to be cooled by air cooling. In this case, the X-ray irradiation unit can have a simpler configuration, can be downsized, and can be more easily transported, as compared with the case where the X-ray irradiation unit is cooled by water cooling or the like.

When the front plate is provided, the slits may be one or a pair, and may be provided symmetrically with respect to the central axis of rotation of the imaging plate. Further, the slit is preferably formed in a fan shape within a range of a predetermined central angle with respect to the central axis of rotation of the imaging plate. When there is one slit, the angle interval for measuring the diffraction ring (rotation angle interval of φ in FIG. 5) when the measurement unit is rotated relative to the measurement target by the rotation mechanism is Δφ (for example, 15 degrees). Then, the central angle of the fan-shaped slit is also set to Δφ (15 degrees), and the imaging plate is rotated by Δφ (15 degrees) by the rotation control unit as the measuring unit is rotated by Δφ (15 degrees). Rotate by (15 degrees). As a result, a part of the diffraction ring corresponding to the angle of φ is exposed to the imaging plate by Δφ (15 degrees). When the measurement unit makes one round, the diffraction ring for one round of φ is exposed on the imaging plate. Therefore, the data of this diffractive ring is read corresponding to the angle of φ, and the multiple regression analysis is performed to perform the multiple regression analysis. Axial stress can be obtained.

Further, when the slits are composed of a pair, for example, when the measurement unit is rotated relative to the measurement target by the rotation mechanism, the angle interval for measuring the diffraction ring is Δφ (for example, 15 degrees), and it is fan-shaped. The central angle of the slit is set to Δφ / 2 (7.5 degrees), and the imaging plate is rotated by Δφ (15 degrees) relative to the measurement unit by the rotation mechanism. Rotate by / 2 (7.5 degrees). As a result, a part of the diffraction ring corresponding to the angle of φ is exposed to the imaging plate by Δφ / 2 (7.5 degrees). When the measurement unit is rotated once, the diffraction ring for φ1 circumference is exposed on the imaging plate. Therefore, the triaxial stress of the measurement target can be obtained by reading the data of this diffraction ring and performing multiple regression analysis. .. Further, at this time, since each slit corresponds to the −η direction and the + η direction of the imaging plate, the triaxial stress can be obtained with high accuracy.

In addition, when the front plate is provided, the measurement unit detects the diffraction ring through the slit while rotating the imaging plate, so that the influence of parts other than the slit can be eliminated and high-quality diffraction ring data can be obtained. Obtainable. The measuring unit is preferably configured by attaching a front plate to the X-ray diffractometer described in Patent Document 3.

In the portable triaxial stress measuring device according to the present invention, the X-ray irradiation unit is configured to irradiate the X-ray through a collimator having one or more pores having a diameter of 0.1 to 2 mm. Is preferable. In this case, it is possible to irradiate a desired local area to be measured with X-rays while suppressing a decrease in the intensity of X-rays. The collimator may be a pinhole type, but is preferably a total reflection type or a capillary type.

The portable triaxial stress measuring device according to the present invention may have an angle adjusting mechanism provided so as to be able to adjust the irradiation angle of the X-ray with respect to the surface to be measured. In this case, the angle adjustment mechanism can adjust the X-ray irradiation angle (the angle of Ψ in FIG. 5) to a desired angle to obtain the triaxial stress of the measurement target. In order to obtain a more accurate triaxial stress, the X-ray irradiation angle is preferably an angle of incidence with respect to the surface to be measured, which is 30 to 70 degrees.

According to the present invention, it is possible to provide a portable triaxial stress measuring device capable of easily obtaining triaxial stress without moving a measurement target while maintaining measurement accuracy.

It is a vertical cross-sectional view which shows the use state of the portable triaxial stress measuring apparatus of embodiment of this invention. It is a side view which shows the internal structure of the measuring unit, and the stress acquisition part of the portable triaxial stress measuring apparatus shown in FIG. (A) Front view showing the imaging plate and the front plate of the portable triaxial stress measuring device shown in FIG. 1, (b) Front view showing the diffraction ring exposed to the imaging plate, (c) Deformation of the front plate. It is a front view which shows an example. It is a graph of _{the residual stress σ xx} of the sample surface with respect to the X-ray irradiation angle which shows the stress measurement result by the portable triaxial stress measuring apparatus shown in FIG. It is a perspective view which shows the relationship between a sample, a coordinate axis, and angles ω, φ, Ψ in stress measurement by an X-ray stress measuring apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show a portable triaxial stress measuring device according to an embodiment of the present invention.
As shown in FIGS. 1 and 2, the portable 3-axis stress measuring device 10 is configured to be portable and includes a measuring unit 11, a support portion 12, and a stress acquisition portion 13.

As shown in FIG. 2, the measuring unit 11 includes an X-ray irradiation unit 21, a diffraction light receiving unit 22, and a data reading unit 23. The measuring unit 11 may be configured by using a commercially available portable X-ray residual stress measuring device (for example, "μ-X360" manufactured by Pulsetec Industrial Co., Ltd.). The X-ray irradiation unit 21 is configured to irradiate X-rays through a plurality of total reflection type collimators having one or more pores having a diameter of 0.1 to 2 mm. Further, the X-ray irradiation unit 21 is configured to be cooled by air cooling.

The diffraction light receiving unit 22 is arranged on the X-ray irradiation direction side of the X-ray irradiation unit 21, and has a rotary table 22a, an imaging plate 22b, a front plate 22c, and a rotation control unit 22d. The rotary table 22a and the imaging plate 22b have a disk shape of the same size, and each has a through hole in the center. The front plate 22c is fixed to the housing of the measurement unit 11, and is coaxial with the through holes of the rotary table 22a and the imaging plate 22b when X-rays are irradiated from the X-ray irradiation unit 21 (when the diffraction ring is detected). It has a through hole of 22 g. The rotary table 22a, the imaging plate 22b, and the front plate 22c are arranged in this order from the X-ray irradiation unit 21 so as to be perpendicular to the X-rays emitted from the X-ray irradiation unit 21.

The imaging plate 22b is coaxially and integrally rotatably attached to the surface of the rotary table 22a on the side opposite to the X-ray irradiation unit 21. The front plate 22c is arranged parallel to the imaging plate 22b with a gap between the front plate 22c and the imaging plate 22b. As shown in FIG. 3A, the front plate 22c has one slit 22e provided so as to extend outward from the center thereof. The slit 22e is formed in a fan shape within a range of a predetermined central angle.

The rotation control unit 22d is arranged between the X-ray irradiation unit 21 and the rotary table 22a. The rotation control unit 22d supports them through the through holes of the rotary table 22a and the imaging plate 22b, and moves them integrally to obtain a data detection position (the position of the solid line in FIG. 2) and a data reading position. It can be positioned at (the position of the alternate long and short dash line in FIG. 2). The rotation control unit 22d is configured so that the rotary table 22a can be rotated around the central axis of each through hole and the rotation angle thereof can be controlled. As a result, the rotation control unit 22d can control the rotation angle of the imaging plate 22b via the rotation table 22a. The diffraction light receiving unit 22 extends through the center of each through hole of the rotation control unit 22d, the rotary table 22a, and the imaging plate 22b so that the X-rays emitted from the X-ray irradiation unit 21 at the data detection position pass through. It has an X-ray passage hole 22f. As a result, the diffraction light receiving unit 22 can irradiate the X-rays emitted from the X-ray irradiation unit 21 at the data detection position to the outside of the measurement unit 11 from the X-ray passage hole 22f through the through hole 22g of the front plate 22c. It has become.

When the measurement unit 11 irradiates the measurement target 1 with X-rays from the X-ray irradiation unit 21 through the X-ray passage hole 22f and the through hole 22g of the front plate 22c at the data detection position, the measurement unit 11 is diffracted by the measurement target 1. The X-ray diffracted ring can be detected by the imaging plate 22b. At this time, the measurement unit 11 passes through the slit 22e of the front plate 22c arranged on the upstream side of the imaging plate 22b with respect to the traveling direction of the diffracted X-rays while rotating the imaging plate 22b by the rotation control unit 22d. , The diffractive ring is configured to be detected by the imaging plate 22b.

The data reading unit 23 positions the rotary table 22a and the imaging plate 22b at the data reading position by the rotation control unit 22d, then irradiates a laser beam from the data reading unit 23, and rotates the rotary table 22a by the rotation control unit 22d. It is moved and the intensity of the reflected light generated at the laser beam irradiation position is detected together with the rotation angle and the moving position. Since the intensity of the reflected light corresponds to the intensity of the diffracted light of X-rays and the rotation angle and the moving position are the laser beam irradiation positions, the intensity of the reflected light, the rotation angle and the moving position are the data of the diffraction ring. As a result, the data reading unit 23 is configured to read the data of the diffraction ring detected by the imaging plate 22b.

After detecting the diffraction ring by the imaging plate 22b at the data detection position, the measurement unit 11 positions the rotary table 22a, the imaging plate 22b and the front plate 22c at the data reading position by the rotation control unit 22d, and the measurement unit 11 positions the diffraction ring at the data reading position. It is configured to read the detected diffraction ring data.

As shown in FIG. 1, the support portion 12 has a support body 24, a rotation mechanism 25, and an angle adjustment mechanism 26 so as to be able to support the measurement unit 11. The support 24 has a dome shape and is configured to be able to be installed on the measurement target 1 so as to cover the measurement position. The rotation mechanism 25 is attached to the central portion inside the support 24. The rotation mechanism 25 has a rotation portion 25a that can be rotated to a set rotation angle with a rotation shaft that coincides with the central axis of the support portion 12. The angle adjusting mechanism 26 has an elongated arc shape, one end of which is fixed to the rotating portion 25a, and the other end of the angle adjusting guide rail 26a provided so as to extend toward the edge of the support 24, and a housing of the measuring unit 11. The body can be attached, and the angle changing portion 26b is provided so as to be movable along the angle adjusting guide rail 26a.

The measurement unit 11 is attached to the angle changing portion 26b of the angle adjusting mechanism 26 so that the intersection of the central axis of the support portion 12 and the optical axis of the X-rays emitted from the measuring unit 11 matches the surface of the measurement target 1. Has been done. The support portion 12 is measured by the rotation mechanism 25 in a state where the incident angle of X-rays with respect to the surface of the measurement position of the measurement target 1 is constant about the axis perpendicular to the surface of the measurement position of the measurement target 1. The measuring unit 11 is rotatably provided with respect to 1. Further, the support portion 12 is provided with an angle adjusting mechanism 26 so that the irradiation angle of X-rays from the X-ray irradiation unit 21 with respect to the surface of the measurement position of the measurement target 1 can be adjusted. As a result, when the rotation mechanism 25 is rotated, the X-rays emitted from the measurement unit 11 are around the central axis of the support portion 12 at a set incident angle while the X-ray incident point on the surface of the measurement target 1 is fixed. The direction of incidence changes.

As shown in FIG. 2, the stress acquisition unit 13 is composed of a computer and is connected to the data reading unit 23 and the rotation control unit 22d of the measurement unit 11. The stress acquisition unit 13 measures from the data of the X-ray diffraction ring detected and read at a plurality of different rotation positions when the measurement unit 11 is rotated relative to the measurement target 1 by the rotation mechanism 25. It is configured to obtain the triaxial stress of object 1.

Next, the action will be described.
The portable 3-axis stress measuring device 10 uses a rotating mechanism 25 to rotate the measuring unit 11 with respect to the measurement target 1 (rotation of φ in FIG. 5), and at a plurality of different rotation positions, the X-ray diffractometric ring is rotated. Obtainable. From the diffracted rings at a plurality of different φ rotation positions thus obtained, the optimum triaxial stress can be obtained by performing multiple regression analysis by the stress acquisition unit 13 in the same manner as in the 2D method.

In a specific example, the portable triaxial stress measuring device 10 performs measurement while rotating the measuring unit 11 by the rotating mechanism 25 in a state where the X-ray irradiation angle is adjusted and fixed by the angle adjusting mechanism 26. At this time, when the measurement unit 11 is rotated by the rotation mechanism 25, the angle interval for measuring the diffraction ring (rotation angle interval of φ in FIG. 5) is set to 15 degrees, and the central angle of the slit 22e of the front plate 22c is also 15 degrees. The rotation control unit 22d rotates the imaging plate 22b by 15 degrees in accordance with the rotation mechanism 25 rotating the measuring unit 11 by 15 degrees. As a result, a part of the diffraction ring corresponding to the angle of φ is exposed to the imaging plate 22b by 15 degrees. As shown in FIG. 3 (b), when the measurement unit 11 is rotated once, the diffraction ring for one cycle of φ is exposed on the imaging plate 22b. Therefore, the data of this diffraction ring is read corresponding to the angle of φ. Optimal triaxial stress can be obtained by performing multiple regression analysis. In this way, the portable triaxial stress measuring device 10 can obtain the triaxial stress without moving the measurement target 1.

Further, the portable triaxial stress measuring device 10 can perform measurement at a place where the measurement target 1 exists without cutting out a sample from the measurement target 1. Thereby, the influence of the stress applied to the sample at the time of cutting out can be eliminated, and a more accurate triaxial stress can be obtained. In addition, it is possible to measure at joints between members such as welding and brazing interfaces, and the tips of cracks, which have been difficult to measure until now. In this way, the portable 3-axis stress measuring device 10 can be used for improving the yield of the production line and diagnosing the life of infrastructure such as bridges, tunnels, and nuclear power plants.

Further, since the portable 3-axis stress measuring device 10 can easily rotate and move the measuring unit 11 to each measurement position while the X-ray incident point is fixed by the rotating mechanism 25, the measuring unit 11 can perform the measurement. It is possible to prevent the accuracy from being lowered due to the deviation of the installation position, and it is possible to easily obtain the triaxial stress while maintaining the measurement accuracy. Further, the angle adjusting mechanism 26 can adjust the X-ray irradiation angle (angle of Ψ in FIG. 5) to a desired angle to obtain the triaxial stress of the measurement target 1.

Since the portable 3-axis stress measuring device 10 detects the diffraction ring through the slit 22e while rotating the imaging plate 22b in the measuring unit 11, it is possible to eliminate the influence of the portion other than the slit 22e, and the quality is high. Data of the diffractive ring can be obtained. Further, in the portable 3-axis stress measuring device 10, since the X-ray irradiation unit 21 is air-cooled, the X-ray irradiation unit 21 can be made simpler and smaller than the one that is cooled by water cooling. It can be made easier to carry.

As shown in FIG. 3C, the slits 22e of the front plate 22c may be paired and provided symmetrically with respect to the center of the front plate 22c. In this case, for example, when the measurement unit 11 is rotated by the rotation mechanism 25 and the angle interval for measuring the diffraction ring is 15 degrees, the central angle of each slit 22e of the front plate 22c is 7.5 degrees. The rotation control unit 22d rotates the imaging plate 22b by 7.5 degrees as the rotation mechanism 25 rotates the measurement unit 11 by 15 degrees relative to the measurement target 1. As a result, a part of the diffraction ring corresponding to the angle of φ is exposed to the imaging plate 22b by 7.5 degrees. When the measurement unit 11 makes one round, the diffraction ring for one round of φ is exposed on the imaging plate 22b. Therefore, the data of this diffractive ring is read corresponding to the angle of φ, and the measurement target is performed by performing multiple regression analysis. The triaxial stress of 1 can be obtained. Further, at this time, since each slit 22e corresponds to the −η direction and the + η direction of the imaging plate 22b, the triaxial stress can be obtained with high accuracy.

Further, the portable triaxial stress measuring device 10 does not have to have the front plate 22c. In this case, when the measurement unit 11 is rotated by the rotation mechanism 25, one diffraction ring is detected at each rotation position where the diffraction ring is measured, so that each time the diffraction ring is detected at each rotation position, diffraction is performed. Read the ring data. When the measurement unit 11 is rotated once, data of a plurality of diffraction rings corresponding to a plurality of rotation positions for one rotation can be obtained. Therefore, the triaxial stress of the measurement target 1 is determined based on the data of the plurality of diffraction rings. Can be sought.

The triaxial stress was measured on a columnar sample of SCM420 (chromoly molybdenum steel) using the portable triaxial stress measuring device 10. A residual compressive stress was previously applied to one surface of the SCM420 sample by heat treatment, and the residual compressive stress was measured. The measurement was performed at a plurality of angles at which the X-rays were incident on the surface of the sample from 25 degrees to 75 degrees, and the triaxial stress was determined at each angle. At this time, the rotation angle at each incident angle was set to 15 degrees. The measurement results of the residual compressive stress are shown in Table 1 and FIG. Table 1 shows the triaxial stresses when the X-ray incident angles are 25 degrees, 35 degrees, 45 degrees, and 65 degrees. Further, FIG. 4 shows only _{the residual stress σ xx on the surface.}

For comparison, Table 1 shows the results of calculating the triaxial stress by the 2D method using a stationary X-ray stress measuring device manufactured by Bruker AXS for the same sample. And shown in FIG. Further, the result of obtaining the surface stress by ^{the sin 2 Ψ method is shown in FIG.}

_{As shown in FIG. 4, it was confirmed that the residual stress σ xx} obtained from the portable triaxial stress measuring device 10 showed a value close to that obtained by other methods. In the portable triaxial stress measuring device 10, it is considered that the X-ray irradiation angle τ should be in the range of 30 degrees to 70 degrees.

1 Measurement target 10 Portable 3-axis stress measuring device 11 Measuring unit 21 X-ray irradiation unit 22 Diffraction light receiving unit 22a Rotation table 22b Imaging plate 22c Front plate 22d Rotation control unit 22e Slit 22f X-ray passage hole 22g Through hole 23 Data reading Part 12 Support part 24 Support 25 Rotation mechanism 25a Rotation part 26 Angle adjustment mechanism 26a Angle adjustment guide rail 26b Angle change part 13 Stress acquisition part

51 Crystal sample

Claims (5)

A measurement unit having an X-ray irradiation unit that irradiates an X-ray to a measurement target and a diffraction light receiving unit that can detect a diffraction ring that is an image of the diffracted light of the X-rays diffracted by the measurement target. When,
With the X-ray irradiation angle with respect to the surface of the measurement target constant, the measurement unit is relative to the measurement target with the axis perpendicular to the surface of the measurement target to be irradiated with the X-ray as the center. A rotating mechanism that can be rotated
From the diffraction rings of the plurality of detected at different rotational positions were the X-ray when the measuring units are relatively rotated by the rotation mechanism, and a stress obtaining unit for obtaining a triaxial stress of the measurement object ,
The diffraction receiving unit has a through hole in the central portion for passing X-rays emitted from the X-ray irradiation unit, and detects the diffraction ring rotatably provided about the central axis of the through hole. An imaging plate for this purpose, a front plate arranged on the upstream side of the imaging plate with respect to the traveling direction of the diffracted X-rays and provided so as to cover the imaging plate, and a rotation according to the rotation mechanism. It has a rotation control unit that rotates the imaging plate.
The front plate has a slit provided so as to extend outward from the central axis of rotation of the imaging plate.
While rotating the imaging plate by the rotation control unit, the measurement unit detects the diffraction ring by the imaging plate through the slit, and detects the diffraction ring detected by the imaging plate in the rotation control unit. Is configured to read from the imaging plate while rotating the imaging plate.
The stress acquisition unit is a portable triaxial stress measuring device , characterized in that the triaxial stress of the measurement target is obtained from the data of the diffractive ring read by the measuring unit. The portable triaxial stress measuring device according to claim 1, wherein the X-ray irradiation unit is configured to be cooled by air cooling. The portable triaxial stress measuring device according to claim 1 or 2 , wherein the slits are composed of a pair and are provided symmetrically with respect to the central axis of rotation of the imaging plate. Any one of claims 1 to 3 , wherein the X-ray irradiation unit is configured to irradiate the X-ray through a collimator having one or more pores having a diameter of 0.1 to 2 mm. The portable triaxial stress measuring device according to the section. The portable triaxial stress measuring device according to any one of claims 1 to 4 , further comprising an angle adjusting mechanism provided so as to be able to adjust the irradiation angle of the X-ray with respect to the surface of the measurement target.