JP5804469B2 - Multi-axis load test apparatus and method - Google Patents

Description

  The present invention relates to a multiaxial load test apparatus and method for structural materials used for structures, members, parts, and the like.

  Metal materials are listed as typical structural materials used for structures, members, parts, etc., but when metal materials are used as structural materials, various tests are conducted to verify the durability required as structural materials. Has been done. Among the mechanical tests, tensile tests, compression tests, bending tests, torsion tests, and other tests are performed to measure the mechanical strength by applying various loads to the material. Fatigue tests are conducted to analyze the fracture phenomena that occur in materials.

  In a load test in which a mechanical load is applied to a material, various load states are realized inside the material by applying a load such as an axial load, a bending load, or a torsion load to the material. The load state inside the material is generally expressed in the state of stress and strain. However, when the direction of principal stress or principal strain acts only in one axial direction, it is called a uniaxial state. When acting in a plurality of axial directions, it is called a multiaxial state. And it is known that the load state in an actual structural material is a multiaxial state in most cases.

  Therefore, in order to verify the mechanical strength related to the structural material, it is necessary to perform a test while setting the structural material in a multiaxial state. As a method for testing a structural material in such a multiaxial state, for example, Patent Document 1 includes a rotary bending load load mechanism, a torsion load load mechanism, and an axial load load mechanism that operate independently of each other. A fatigue testing device is described that can be operated to act alone or in combination with a plurality of mechanisms. Further, in Patent Document 2, the tensile load and the compressive load in the axial direction of a thin hollow cylindrical test piece, the torsional load around the axis of the test piece, and the internal and external pressure loads from the inside and outside of the test piece are described. A multi-axis load testing machine that applies loads by combining various types of loads is described. Moreover, as a test apparatus for applying an internal pressure or an external pressure to a cylindrical test piece, for example, in Patent Document 3, the end of a steel pipe is attached so as to protrude outward from the pressure vessel, and is drilled in the pressure vessel. In addition, an external pressure load test apparatus is described in which water is supplied from an external pressure water supply port to apply an external pressure to the steel pipe.

JP 50-142279 A JP-A-57-072042 Japanese Patent Laid-Open No. 2001-074624

  In the piping section of a power plant or chemical plant, a mechanical load due to the movement of internal fluid or a change in pressure and a thermal load due to a change in temperature of the internal fluid result in a complicated load state. It is known that a state of non-proportional load in which the direction of principal stress and principal strain changes with time inside the pipe body is known. In the non-proportional load state, the strength of the structural material is more likely to decrease than in the proportional load state in which the directions of principal stress and principal strain are fixed. It is desirable to perform a load test in a non-proportional load state.

  In the test apparatus described in the above-mentioned patent document, it is difficult to set a complex load state such as a non-proportional load state close to an actual use state although it can be set to a multi-axis state. For example, in Patent Document 2, an axial load, a torsional load, and an internal / external pressure load are applied to a hollow cylindrical test piece. The internal pressure and the external pressure are measured from an external hydraulic device to the inside of the test piece. The load state is set by supplying oil to the outside and applying hydraulic pressure. For this reason, piping for supplying hydraulic pressure is required, but it is difficult to set the internal pressure and the external pressure to high pressure because it cannot be in a high pressure state higher than the strength of the piping. Also, when changing the internal pressure and external pressure, it is difficult to change the internal pressure and external pressure accurately at high speed because the hydraulic control is performed through the piping, and it is possible to perform a precise load test in a load state close to the actual use state. There are difficulties.

  Accordingly, an object of the present invention is to provide a multi-axis load test apparatus and method that can perform a load test with high accuracy in a multi-axis state.

A multi-axis load test apparatus according to the present invention is a multi-axis load test apparatus that applies a load to a specimen made of a structural material to perform a load test in a multi-axis state, and is axial with respect to the specimen. An axial pressure applying unit for applying a load to the test piece, a pressure hole for storing a working fluid around the test piece accommodated in the accommodation hole, and a test hole containing the test piece, and the test piece An external pressure applying unit that applies an external pressure to the outer periphery of the specimen by the working fluid by increasing or decreasing the volume of the working space formed between the accommodation hole and the specimen by moving the shaft in the axial direction; It has. Further, based on an axial pressure detection sensor for detecting an axial load applied to the specimen, an external pressure detection sensor for detecting an external pressure applied to the specimen, and a detection signal from the axial pressure detection sensor. An axial pressure control circuit that feedback-controls the axial pressure application unit, and an external pressure control circuit that feedback-controls the external pressure application unit based on a detection signal from the external pressure detection sensor. Furthermore, an internal pressure application unit is provided which is attached to the axial pressure application unit and applies an internal pressure to the sample by a working fluid stored in an internal space of the sample. Furthermore, a torsion applying unit is provided which is attached to the external pressure applying unit and applies a torsional load to the test body connected and fixed to the operating body by rotating the operating body of the external pressure applying unit.

A multiaxial load test method according to the present invention is a multiaxial load test method in which a load test is performed in a multiaxial state by applying a load to a specimen made of a structural material, and a housing formed in a pressure vessel portion. The specimen is accommodated in the hole, the working fluid is stored around the specimen accommodated in the accommodation hole, and the specimen is moved in the axial direction to be formed between the accommodation hole and the specimen. By increasing or decreasing the volume of the working space , an external pressure is applied to the outer periphery of the specimen by the working fluid, and a load test is performed by applying a load to the specimen in the axial direction. Furthermore, feedback control is performed so that the external pressure applied based on a detection signal from an external pressure detection sensor for detecting the external pressure applied to the specimen matches a set condition, and an axial load applied to the specimen Based on the detection signal from the shaft pressure detection sensor that detects the feedback, feedback control is performed so that the axial load matches the set condition.

  By having the above-described configuration, the present invention can perform a load test with high accuracy in a multi-axis state.

It is a schematic block diagram regarding embodiment which concerns on this invention. It is the elements on larger scale regarding a pressure vessel part. It is a block block diagram regarding the operation control of embodiment described in FIG.

  Hereinafter, embodiments according to the present invention will be described in detail. FIG. 1 is a schematic configuration diagram relating to an embodiment of the present invention. In the multi-axis load test apparatus, a support frame 2 is erected on the upper surface of a base 1, and an upper mount 3 and a lower mount 4 are supported on the support frame 2. A pressure vessel portion 5 is supported and fixed to the support frame 2 substantially in the middle between the upper mounting base 3 and the lower mounting base 4.

  An axial pressure application unit 6 for applying an axial load is supported and fixed on the upper surface of the upper mounting base 3, and an internal pressure application unit 7 is provided above the axial pressure application unit 6. The axial pressure application section 6 is formed such that a cylinder section 60 that stores hydraulic fluid for hydraulic oil is formed so that the axial direction is along the axial pressure application direction (vertical direction). Is slidable in the axial pressure application direction (vertical direction). An operating body 62 is extended on the axial pressure application side of the piston portion 61, and the operating body 62 penetrates downward from the mounting holes formed in the cylinder portion 60 and the mounting base 3 and can move in the axial pressure applying direction. Is attached. Further, a connecting body 63 extends upward on the opposite side of the piston portion 61 from the axial pressure application side, and the distal end portion of the connecting body 63 is inserted into the internal pressure application portion 7 as described later.

  Inside the cylinder portion 60, hydraulic oil is supplied from an unillustrated hydraulic pump to the upper and lower working spaces of the piston portion 61 via an oil passage 64. And by controlling the hydraulic pressure of the hydraulic fluid to the upper working space and the hydraulic pressure of the hydraulic fluid to the lower working space, the piston 61 is moved up and down and the hydraulic pressure is applied to the specimen 100 via the working body 62. Axial pressure is applied.

  The internal pressure application unit 7 is formed such that a cylinder unit 70 that stores hydraulic fluid for hydraulic oil is formed so that the axial direction is along the axial pressure application direction (vertical direction), and a piston unit 71 is provided in the cylinder unit 70. It is slidable in the axial pressure application direction (vertical direction). An oil reservoir 72 is formed inside the piston portion 71, and the connecting body 63 is attached to an attachment hole formed in the piston portion 71 along the axial pressure application direction downward from the oil reservoir 72. Is slidably inserted. The connecting body 63, the piston portion 61, and the operating body 62 are formed so that a communication oil path 73 penetrates along the central axis. The communication oil path 73 is connected to an internal space of the specimen 100 described later and an oil reservoir. The unit 72 communicates with the unit 72.

  Inside the cylinder portion 70, hydraulic oil is supplied from an unillustrated hydraulic pump to the working spaces on both the upper and lower sides of the piston portion 71 via an oil passage 74. Then, by controlling the hydraulic oil pressure to the upper working space and the hydraulic oil pressure to the lower working space, the piston part 71 is moved up and down to move the oil storage part 72 up and down with respect to the coupling body 63. Can be.

  In a state where the oil reservoir 72 is filled with hydraulic oil, when the oil reservoir 72 moves downward with respect to the coupling body 63, the tip of the coupling body 63 is further inserted into the oil reservoir 72 and the oil is stored. The volume in the reservoir 72 is reduced, and the hydraulic oil corresponding to the reduced volume flows through the communication oil passage 73 and flows out into the internal space of the specimen 100. Moreover, when the oil storage part 72 moves upward with respect to the connection body 63, the insertion part in the oil storage part 72 in the front-end | tip part of the connection body 63 becomes short, and the part in the oil storage part 72 is equivalent to it. The volume increases, and the hydraulic oil in the specimen 100 flows through the communication oil passage 73 and flows into the oil reservoir 72. Therefore, by moving the piston part 71 up and down, the working oil is circulated between the oil storage part 72 and the internal space of the specimen 100 to apply an internal pressure to the specimen 100.

  An accommodation hole 50 for accommodating the specimen 100 is formed in the pressure vessel portion 5 so as to penetrate the central portion. FIG. 2 is a partially enlarged view of the pressure vessel unit 5. The specimen 100 has a substantially cylindrical shape and is narrowed so that the central portion is thin. The lower support portion 101 and the upper support portion 102 are formed thick, and although not shown, a groove for mounting a sealing O-ring is formed. Further, the outer diameter of the lower support portion 101 is set to be larger than that of the upper support portion 102. An internal space 104 is formed in the specimen 100 along the central axis with a predetermined inner diameter. As for the shape of the specimen 100, the outer dimensions and thickness may be set so that a load state corresponding to the multiaxial load state generated in the structural material is applied.

  The accommodation hole 50 is formed in a circular shape so as to substantially coincide with the outer diameter of the lower support portion 101 of the specimen 100 at the lower portion, and the diameter of the accommodation hole 50 increases toward the upper portion of the upper support portion 102 of the specimen 100. A working space for storing hydraulic oil for applying an external pressure to the working part 103 of the specimen 100 is formed in a circular shape wider than the outer diameter. The upper opening of the accommodation hole 50 is sealed with a lid 51, and a mounting hole 51 a is formed at the center of the lid 51 so as to substantially match the outer diameter of the upper support portion 102 of the specimen 100. .

  And by arranging the lower support portion 101 of the specimen 100 in close contact with the lower part of the accommodation hole 50 and arranging the upper support portion 102 of the test specimen 100 in close contact with the mounting hole 51a, the hydraulic oil is disposed. The working space to be stored is set in a watertight state around the working portion 103 of the specimen 100. The lid 51 is provided with a pair of communication passages 51b and 51c communicating with the working space. The hydraulic fluid is supplied from one communication passage, and the internal air is supplied from the other communication passage. By pulling out, the working space can be filled with hydraulic oil. Then, one of the communication passages is closed with a sealing plug or the like in a state where the hydraulic oil is filled, and an external pressure detection sensor described later is attached to the other communication passage, whereby the applied external pressure can be detected.

  An operating body 62 is connected and fixed to the upper support portion 102 of the specimen 100 set so as to protrude upward from the lid 51, and a communication oil path 73 formed in the inside of the operating body 62 and the specimen. 100 internal spaces 104 are connected and communicated. In addition, the abutting body 52 is attached to the lower surface of the lower support portion 101 of the specimen 100 set so as to protrude downward from the pressure vessel portion 5. A communication path 52a is formed in the contact body 52 so as to connect to and communicate with the internal space 104 of the specimen 100, and one end of the communication path 52a is opened to the outside to serve as a supply port. Although not shown in FIG. 1, a flow pipe that communicates between the oil reservoir 72 and the outside is provided in the internal pressure application unit 7, and hydraulic oil is introduced from the supply port of the communication path 52 a to thereby create the internal space 104. Is circulated so as to flow into the oil reservoir 72 through the communication oil passage 73 and to let the hydraulic oil flow out from the flow pipe. And after setting the oil storage part 72, the communicating oil path 73, the internal space 104, and the inside of the communicating path 52a to the state where the air filled with the hydraulic fluid escaped, the communicating path 52a and the flow pipe are sealed with a stopper. In this way, the oil reservoir 72, the communication oil passage 73, and the entire internal space 104 can be set to be filled with hydraulic oil.

  An external pressure application unit 8 for applying external pressure is supported and fixed on the lower surface of the lower mounting base 4, and a torsion application unit 9 for applying a torsion load is provided below the external pressure application unit 8. Yes. The external pressure application unit 8 is formed such that a cylinder unit 80 that stores hydraulic fluid for hydraulic oil is formed so that the axial direction is along the axial pressure application direction (vertical direction), and a piston unit 81 is provided in the cylinder unit 80. It is slidable in the axial pressure application direction (vertical direction). An operating body 82 is extended on the axial pressure application side of the piston portion 81, and the operating body 82 penetrates upward from mounting holes formed in the cylinder portion 80 and the lower mounting base 4 and moves in the axial pressure application direction. It is attached as possible. The working body 82 is connected and fixed to the abutting body 52 via the connecting body 83 at the upper end portion thereof. Further, on the side opposite to the axial pressure application side of the piston portion 81, a rotational drive body 91 of the torsion application portion 9 is connected and fixed and extends downward.

  Inside the cylinder portion 80, hydraulic oil is supplied from an unillustrated hydraulic pump to the upper and lower working spaces of the piston portion 81 via an oil passage 84. Then, by controlling the hydraulic oil pressure to the upper working space and the hydraulic oil pressure to the lower working space, the piston 81 is moved up and down to connect the connecting body 83 and the contact body 52 via the operating body 82. The hydraulic pressure is applied to the specimen 100 connected to.

  When the specimen 100 is actuated to be pushed up by the external pressure application unit 8, the lower support part 101 of the specimen 100 enters the working space of the pressure vessel 5 and acts as much as the lower support part 101 enters. The volume of the space is reduced. On the other hand, as the specimen 100 is raised, the volume of the working space increases as the upper support portion 102 moves upward, but the outer diameter of the lower support portion 101 is larger than the outer diameter of the upper support portion 102. The volume decrease due to the entry of the lower support portion 101 becomes larger, and the volume of the entire working space decreases as the specimen 100 rises. Further, the volume of the entire working space increases as the specimen 100 is lowered. Therefore, by moving the specimen 100 up and down by the external pressure application unit 8, the hydraulic pressure of the hydraulic oil filled inside can be adjusted by increasing or decreasing the volume of the working space, and the outer circumference of the working part 103 of the specimen 100 can be adjusted. It is possible to adjust the applied external pressure.

  Since the housing hole 50 formed in the pressure vessel portion 5 is filled with the hydraulic oil and the external pressure is applied to the action portion 103 by the vertical movement of the specimen 100, the external pressure is applied with a small amount of hydraulic oil. Therefore, the device can be made compact and the safety of the device can be improved. Further, since the external pressure can be directly changed by the vertical movement of the specimen 100, it is possible to set the pressure to a high pressure, and it is possible to change the external pressure at high speed and accurately. In addition, since the amount of hydraulic oil is small and does not enter or exit from the outside, temperature control becomes easy, various test conditions can be set with high accuracy, and a multiaxial load test of a wide range of structural materials can be performed.

  The torsion applying unit 9 is provided with an oil reservoir 90 around the rotary drive body 91, and the rotary drive body 91 is set to be slidable in the axial direction with respect to the oil reservoir 90. Then, hydraulic oil is supplied to the oil reservoir 90 from the outside by a hydraulic pump or the like, and the rotary drive body 91 is rotated about the axis. For example, a blade-like working part is formed around the rotary driving body 91 in the working space formed in the oil reservoir 90, and the pressure of the working oil is applied to the working part to It can be rotated around its axis.

  The piston 81 and the actuating body 82 are also rotated together by the rotation operation of the rotation driving body 91, and the lower support portion 101 of the specimen 100 is connected from the actuating body 82 via the connecting body 83 and the contact body 52. Acts to rotate around the axis. Since the upper support portion 102 of the specimen 100 is connected and fixed to the operating body 62, the upper support portion 102 is fixed to the action portion 103 of the specimen 100 with the upper support portion 102 being fixed against rotation about the axis. A torsional load accompanying the rotation operation of the side support portion 101 around the axis is applied.

  Although not shown, a plurality of strain gauges that detect axial strain, circumferential strain, and torsional strain are pasted and accommodated on the outer peripheral surface of the action portion 103 of the specimen 100. Based on the detection signal from the strain gauge, a change due to the load of the specimen 100 during the load test can be detected in real time. In addition, an axial pressure detection sensor S1 such as a load cell is attached to the lower surface of the upper mounting base 3 in order to detect the axial load, so that the axial load applied by the axial pressure application unit 6 is always detected. It has become. An external pressure detection sensor S2 such as a pressure gauge is attached to the opening of the communication passage 51c of the lid 51 that communicates with the accommodation hole 50 of the pressure vessel 5, so that the oil pressure in the accommodation hole 50 is always detected. It has become. The operating body 62 is formed with a communication passage communicating with the communication oil passage 73 in a direction orthogonal to the axial direction, and an internal pressure detection sensor S3 such as a pressure gauge is attached to an opening portion of the communication passage. . The internal pressure detection sensor S3 always detects the hydraulic pressure in the internal space 104 of the specimen 100. In addition, a torsion detection sensor S4 that detects the amount of torsion using a shaft / torque force meter or the like is disposed inside the connection body 83, and the torsion load applied to the specimen 100 is always detected. Yes. In addition, it can detect also about the load of an axial direction by using an axis | shaft torque torque meter.

  When setting the specimen 100 in the test apparatus, first, the specimen 100 is inserted into the accommodation hole 50 of the pressure vessel portion 5, and the lower support portion 101 of the specimen 100 is connected to the upper surface of the contact body 52. The upper support portion 102 is connected and fixed to the lower surface of the operating body 62. Then, the working oil is injected into the internal space 104 of the specimen 100 and the working oil is injected into the accommodation hole 50 so that the inside and the outside of the action portion 103 of the specimen 100 are filled with the working oil.

  Next, the internal pressure application unit 7 is operated to move the piston unit 71 downward, and is operated until the pressure in the internal space 104 of the specimen 100 reaches a predetermined internal pressure. Then, the external pressure application unit 8 is operated to move the piston unit 81 upward so that the specimen 100 is pushed up by the operating body 82 and operates until the pressure in the working space in the accommodation hole 50 reaches a predetermined external pressure. Let At that time, the operating body 62 of the axial pressure applying unit 6 is operated so as to rise in conjunction with the ascending operation of the operating body 82. Further, the internal pressure generated in the internal pressure application unit 7 changes with the movement of the operating body 62, but is maintained at a predetermined internal pressure by performing feedback control based on the detection signal of the internal pressure detection sensor S3.

  In a state where the internal pressure and the external pressure are set to predetermined pressures, the axial pressure application unit 6 is operated to move the piston unit 61 downward, and the sample 100 is operated until a predetermined axial pressure is applied. At that time, the specimen 100 is pushed down, but the external pressure application unit 8 maintains the predetermined external pressure by performing feedback control based on the detection signal of the external pressure detection sensor S2. Similarly, the internal pressure generated in the internal pressure application unit 7 changes as the operating body 62 moves, but is maintained at a predetermined internal pressure by feedback control.

  With the internal pressure, the external pressure, and the axial pressure set to predetermined pressures, the torsion applying section 9 is operated to rotate the rotary drive body 91, and the lower support section 101 of the specimen 100 is rotated about the axis by a predetermined twist amount. Operate to rotate.

  As described above, the axial pressure application unit 6, the internal pressure application unit 7, the external pressure application unit 8 and the torsion application unit 9 are independently operated, and each application unit is feedback-controlled based on the detection signal of each detection sensor. Thus, a predetermined pressure state or a twisted state can be maintained, and any complicated stress state can be easily realized. In addition, since it is configured to be pressed in the axial direction by the axial pressure application unit 6 from one side of the specimen 100 and to be pressed in the opposite direction from the axial pressure application unit 6 by the external pressure application unit 8 from the other side. The shaft pressure and the external pressure can be set to a predetermined pressure state by feedback control while the specimen 100 is stable.

  Then, the load test can be stably performed in various multiaxial states by applying an axial load, a torsional load, and an internal / external pressure load to the action part 103 of the specimen 100 with high accuracy. Further, even when a fatigue test is performed, by controlling the operation of each application unit independently, each load can be accurately and independently changed repeatedly, and a highly accurate fatigue test can be performed. It is also possible to change the load by increasing the response speed, and it is possible to perform a load test with a wide range of condition settings.

  FIG. 3 is a block configuration diagram relating to operation control of the embodiment described in FIG. 1. The multi-axis load test apparatus includes an apparatus main body 200 and a control apparatus 300, and the apparatus main body 200 has already been described in detail with reference to FIGS. The control device 300 includes a control unit 310 that controls the entire device, an input unit 311 that inputs setting data and the like necessary for a load test, a display unit 312 that displays test results and the like, programs and data necessary for controlling the device, and the like. And a transmission / reception unit 314 that receives a detection signal from a strain gauge and a detection sensor and transmits a control signal to the control circuit of each application unit. Further, in order to control the operation of each application unit, an axial pressure control circuit 320 that controls the operation of the axial pressure application unit 6, a torsion control circuit 321 that controls the operation of the torsion application unit 9, and an external pressure that controls the operation of the external pressure application unit 8 A control circuit 322 and an internal pressure control circuit 323 for controlling the operation of the internal pressure application unit 7 are provided, and a switching circuit 330 for switching to feedback control by axial pressure and torsion or feedback control by strain is provided.

  The control unit 310 includes a condition setting unit 310a, a detection data processing unit 310b, and an analysis unit 310c. In the condition setting unit 310a, input data from the input unit 311 and setting data and detection data stored in the storage unit 313 are included. Then, a condition setting for performing a load test is performed based on the calculation data and the like, and a control signal corresponding to the setting condition is transmitted to each control circuit via the transmission / reception unit 314. In the detection data processing unit 310b, the strain gauges S5 and S6 provided in the action unit 103 of the specimen 100, the detection sensors S2 and S3 that detect the external pressure and the internal pressure, and the detection sensors S1 and S4 that detect the axial pressure and the torsion amount. Data processing is performed based on the transmitted detection data, and various stress components (axial principal stress, circumferential principal stress, shear stress, etc.) acting on the specimen 100, various strain components (axial strain, circumferential strain, Shear strain etc. are calculated. The obtained detection data and calculation data are stored in the storage unit 313. The analysis unit 310c analyzes data based on test results such as detection data and calculation data stored in the storage unit 313.

  The external pressure control circuit 322 performs feedback control so that the detection signal of the external pressure detection sensor S2 is input and the external pressure matches the set condition. The internal pressure control circuit 323 performs feedback control so that the detection signal of the internal pressure detection sensor S3 is input and the internal pressure matches the set condition. The shaft pressure control circuit 320 and the torsion control circuit 321 perform feedback control based on the feedback signal from the switching circuit 330. In the case of feedback control using shaft pressure and torsion, a detection signal from the shaft pressure detection sensor S1 is input to the shaft pressure control circuit 320, and feedback control is performed so that the shaft pressure matches the set condition, and detection by the torsion detection sensor S4. A signal is input to the torsion control circuit 321 and feedback control is performed so that the torsion amount matches the set condition. In the case of feedback control using strain, a detection signal from the strain gauge S5 that detects strain in the axial direction is input to the shaft pressure control circuit 320, and feedback control is performed so that the shaft pressure matches the set condition. A detection signal of the strain gauge S6 that detects strain is input to the torsion control circuit 321 and feedback control is performed so that the torsion amount matches the set condition.

  In the embodiment described above, a load is applied by hydraulic pressure using hydraulic oil in the pressure vessel section 5, the axial pressure application section 6, the external pressure application section 8 and the torsion application section 9, but by a method other than hydraulic pressure. A load may be applied and is not particularly limited. For example, a device such as a pressure applying device using a working fluid such as gas or a pressure applying device that operates by electromagnetic action can be used.

  Moreover, since the pressure vessel part 5, the axial pressure application part 6, the internal pressure application part 7, the external pressure application part 8 and the torsion application part 9 are detachably attached to the upper mounting base 3 and the lower mounting base 4, various By appropriately attaching each part according to the load test, it is possible to easily change to a device configuration adapted to the load test. For example, if the apparatus is configured by attaching the axial pressure application unit 6, the internal pressure application unit 7, the external pressure application unit 8 and the torsion application unit 9, it is possible to perform a load test combining internal pressure load, axial load and torsion load. Thus, if the internal pressure application unit 7 is omitted, it is possible to perform a load test combining an axial load and a torsional load. In this case, both the axial load and the torsional load can be detected by using a shaft / torque force meter as the torsion detection sensor S4.

  Further, in the present invention, the load test can be performed by forming the outer shape of the specimen 100 in various shapes other than the cylindrical shape. For example, the load test can be performed even in the case of a prismatic shape or a rectangular tube shape. Is possible. And even in the case of a solid body having no internal space, a load test for applying a load other than the torsional load and the internal pressure load can be performed.

DESCRIPTION OF SYMBOLS 1 ... Base, 2 ... Support frame, 3 ... Upper mounting base, 4 ... Lower mounting base, 5 ... Pressure vessel part, 6 ... Axial pressure application part, 7 ... -Internal pressure application unit, 8 ... external pressure application unit, 9 ... torsion application unit, 50 ... accommodation hole, 100 ... specimen, S1 ... axial pressure detection sensor, S2 ... external pressure detection Sensor, S3 ... Internal pressure detection sensor, S4 ... Torsion detection sensor

Claims (6)

A multi-axis load test apparatus that applies a load to a specimen made of a structural material and performs a load test in a multi-axis state, and an axial pressure application unit that applies a load in an axial direction to the specimen; An accommodation hole for accommodating the specimen is formed and a pressure vessel portion for storing a working fluid around the specimen accommodated in the accommodation hole; and the accommodation hole by moving the specimen in the axial direction A multi-axis load testing apparatus comprising: an external pressure application unit configured to apply an external pressure to an outer periphery of the specimen by the working fluid by increasing or decreasing a volume of a working space formed between the specimen and the specimen .   An axial pressure detection sensor for detecting an axial load applied to the specimen, an external pressure detection sensor for detecting an external pressure applied to the specimen, and the shaft based on a detection signal from the axial pressure detection sensor The multi-axis load test according to claim 1, further comprising: an axial pressure control circuit that feedback-controls the pressure application unit; and an external pressure control circuit that feedback-controls the external pressure application unit based on a detection signal from the external pressure detection sensor. apparatus.   The multiaxial load test apparatus according to claim 1, further comprising an internal pressure application unit that is attached to the axial pressure application unit and applies an internal pressure to the test sample by a working fluid stored in an internal space of the test sample.   The torsion application part which applies the torsional load to the said test body which is attached to the said external pressure application part and rotates the action body of the said external pressure application part and is fixedly connected to the said operation body is provided. The multi-axis load test apparatus according to claim 1. A multi-axial load test method for applying a load to a specimen made of a structural material and performing a load test in a multi-axial state, wherein the specimen is accommodated in an accommodation hole formed in a pressure vessel portion. The working fluid is stored around the specimen accommodated in the hole, and the specimen is moved in the axial direction to increase or decrease the volume of the working space formed between the accommodation hole and the specimen. Thus, a multiaxial load test method in which an external pressure is applied to the outer periphery of the specimen by the working fluid, and a load test is performed by applying a load to the specimen in the axial direction.   Based on the detection signal from the external pressure detection sensor that detects the external pressure applied to the specimen, feedback control is performed so that the external pressure applied matches the set condition, and the axial load applied to the specimen is detected. The multi-axis load test method according to claim 5, wherein feedback control is performed based on a detection signal from an axial pressure detection sensor that performs an axial load so as to match a set condition.

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