True triaxial complex stress loading equipment capable of realizing multiple shear modes

Abstract

The invention provides true triaxial complex stress loading equipment capable of realizing multiple shear modes, and relates to the technical field of mechanical property testing, the true triaxial complex stress loading equipment comprises annular torsion shear, direct shear and true triaxial shear loading methods and devices, and the scheme comprises the following steps: processing a notch in a sample in advance, and reserving a connecting part; the mandrel is arranged to prevent the side wall of the sample from being distorted and deformed inwards in the twisting process; then, respectively applying opposite twisting forces along the diameter to the first edge and the second edge through a twisting device, so that the upper test sample is twisted relative to the lower test sample, and a plurality of anti-deformation surfaces are also arranged on the twisting device; comprising an upper half shear box, a lower half shear box, a front pressing block and a rear pressing block which form an interlocked structure; the upper half shear box pushes the front pressing block to move when normal stress is applied, the front pressing block pushes the lower half shear box to move when lateral force is applied, the lower half shear box pushes the rear pressing block to move when normal stress is applied, and the rear pressing block pushes the upper half shear box to move when lateral force is applied. The two main body experiment devices are connected through a middle transmission device and control respective work. Therefore, the various-mode shear loading method and the various-mode shear loading device provided by the invention can enable the to-be-tested sample to realize different shear modes and to be in a stable shear loading state when the different samples are subjected to torsional shear.

Description

Technical Field

[0001] The invention relates to the technical field of rock mechanics experiments, and in particular to a true triaxial complex stress loading device capable of realizing multiple shear modes, which is suitable for rock mass shear tests under true triaxial stress. Background Art

[0002] Indoor shear tests of rocks are widely used in deep rock engineering, energy development and geophysical research. For example, structural plane slip causes structurally controlled damage to deep rock engineering, fault shear causes wellbore instability during deep oil and gas development, and deep fault creep causes earthquakes. The mechanism research of these disasters is generally carried out through indoor experiments.

[0003] Since the size of rocks used for indoor tests is limited and the size of the loading head of the test device is relatively large, it is generally difficult to directly perform shear tests on rock samples through the loading piston. Shear tests are generally performed using a shear box as the force transmission medium.

[0004] According to the different forms of shear boxes, shear tests can be divided into two types: cylindrical three-dimensional shear boxes and square direct shear boxes. The cylindrical shear box takes into account the influence of confining pressure on the shear mechanical properties of rock, but this shear box generally uses hydraulic oil loading to apply normal confining pressure, making it difficult to conduct shear tests on steady normal stiffness. Currently, the square direct shear box is more commonly used, which can simultaneously conduct tests on steady normal stress or steady normal stiffness.

[0005] However, deep rock mass is in a three-dimensional stress space, and any object is subject to forces from three orthogonal directions of X, Y, and Z. For shear tests, the three principal stresses can be called shear force, normal force, and lateral force. When the rock mass slips along the structural surface, the structural surface and the rock mass are always in a true triaxial stress state. Whether it is a cylindrical three-dimensional shear box or a square direct shear box, the two shear box designs make the stress state of the rock sample unable to reflect the true triaxial stress state, and at least two faces of the rock sample are always in an air-free state, which is inconsistent with reality. Therefore, it is necessary to develop a shear device suitable for testing hard rock under true triaxial stress. Summary of the invention

[0006] In view of the above-mentioned problems, the present invention aims to provide a true triaxial complex stress loading device that can realize multiple shear modes. The stability of sample fixation is improved by clamping the inner and outer walls of the sample with strong glue in combination with round nails. Torsional stress is loaded by a pulley group in combination with a torsion motor, and the torque transmission path is designed to reduce the torque loss caused by slight deformation of the rock sample under the action of torque, thereby improving the accuracy of applying torque to the rock sample.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A true triaxial complex stress loading device capable of realizing multiple shear modes comprises an upper shear fixing mechanism and a lower shear torsion mechanism, and is characterized in that: the upper shear fixing mechanism is slidably connected to the lower shear torsion mechanism, and both the upper shear fixing mechanism and the lower shear torsion mechanism are provided with sample end fixing components for clamping and fixing hollow rock samples, and the lower shear torsion mechanism is also provided with two sets of torque applying components, and the torque applying components apply torque to the hollow rock sample by means of a pulley group combining a fixed pulley and a movable pulley.

[0009] Furthermore, the upper shear fixing mechanism includes four retractable supporting legs, a first mounting plate is fixed on the top of the four supporting legs, a circular first through hole is opened in the center of the first mounting plate, an octagonal through hole is opened on the top of the first through hole, the inscribed circle diameter of the octagonal through hole is larger than the diameter of the first through hole, a sample end fixing assembly corresponding to the upper shear fixing mechanism is clamped in the octagonal through hole, and the bottom of the sample end fixing assembly passes through the first through hole.

[0010] Furthermore, the sample end fixing assembly includes an octagonal plate corresponding to the octagonal through hole, and two groups of sample outer wall fixing assemblies are slidably provided on the octagonal plate, and each group of the sample outer wall fixing assemblies includes two symmetrically arranged sliding rods, and an arc-shaped clamping ring is fixed to the bottom of each sliding rod, and the connecting line of the four clamping rings is a circular structure, and a plurality of fixing nails are provided on the inner side of the clamping ring; a sliding limit through hole for the sliding of the sliding rod is opened on the octagonal plate, and the sliding rod passes through the sliding limit through hole, and the clamping ring is located below the octagonal plate, and two groups of driving assemblies for driving the sliding rod to move are provided between the four sliding rods.

[0011] Further, each group of the driving components includes two mutually perpendicular driving rods, the two driving rods are cross-arranged up and down, and the two driving rods are connected by a fixed block, both ends of each driving rod are threaded through the corresponding sliding rods, and the end of each driving rod is fixed with external teeth, and the ends of the two driving rods corresponding to each other in the two groups of driving components are connected by an annular toothed belt, and the annular toothed belt is meshed with the external teeth;

[0012] The driving rod comprises a first screw rod and a second screw rod with opposite rotation directions, each of the first screw rod and the second screw rod is fixedly connected via a connecting shaft, and the connecting shaft is rotatably connected to the fixed block.

[0013] Furthermore, a sample inner wall fixing assembly is slidably provided on the octagonal plate, and the structure of the sample inner wall fixing assembly is the same as that of the sample outer wall fixing assembly, but the size is smaller than that of the sample outer wall fixing assembly; and the sliding rod in the sample inner wall fixing assembly and the sliding rod in the sample outer wall fixing assembly are alternately arranged along the circumference, and the fixing pins on the sample inner wall fixing assembly are located on the outer walls of the clamping rings corresponding to each other.

[0014] Furthermore, the lower shear and torsion mechanism includes a middle plate and two side plates, the upper shear fixing mechanism is slidably mounted on the middle plate, and the two groups of torque application assemblies are respectively mounted on the two side plates; a support ring is fixedly provided at the top center of the middle plate, a torsion disk is rotatably sleeved on the support ring, and the torsion disk is also provided with a first through hole and an octagonal through hole that are connected up and down, the sample end fixing assembly corresponding to the lower shear and torsion mechanism is clamped in the octagonal through hole, and the installation direction of the sample end fixing assembly corresponding to the lower shear and torsion mechanism is opposite to the installation direction of the sample end fixing assembly corresponding to the upper shear and torsion mechanism.

[0015] Furthermore, the torsion disk is a circular disk structure with two sides symmetrically cut off, and two parallel grooves are provided on the two arc-shaped sides of the torsion disk, and the first fixing columns for fixing the slide rope are fixed on the two opposite corners of the two arc-shaped sides of the torsion disk; the first support columns for installing the torque application assembly are fixed on the two opposite corners of the two side panels.

[0016] Furthermore, the torque application assembly includes a bottom mounting block fixedly mounted on the top of the first support column, and an F-shaped support member fixedly mounted on the side panel, the end of the bottom mounting block away from the first support column is fixedly connected to the top of the middle rod of the F-shaped support member; torsion motors are mounted on the left and right sides of the bottom mounting block, the two torsion motors have different heights, and a hollow pulley is mounted on the output shaft of each torsion motor; an inverted Z-shaped support column is also fixedly mounted on the top of the bottom mounting block, a top mounting block is fixedly mounted on the top of the inverted Z-shaped support column, and two second fixed columns with different heights are respectively fixedly mounted between the inverted Z-shaped support column and the bottom mounting block and the top mounting block, and the second fixed column is also used to fix the slide rope; a pulley group for connecting the slide rope is provided between the bottom mounting block, the top mounting block and the F-shaped support member.

[0017] Further, the pulley block includes a fixed pulley assembly and a movable pulley assembly, the fixed pulley assembly includes a fixed pulley shaft fixedly arranged between the bottom mounting block and the top mounting block, a fixed pulley sleeve is fixedly sleeved on the fixed pulley shaft, the cross section of the fixed pulley sleeve is an I-shaped, and the fixed pulley sleeve is fixedly provided with two circles of first sliding clamps along the circumferential direction, and the two first sliding clamps are rotatably connected to the hollow pulley;

[0018] The movable pulley assembly includes a movable pulley sleeve slidably arranged between the top rod and the middle rod of the F-shaped support member. The cross-section of the movable pulley sleeve is also I-shaped, and first sliding grooves are provided on the two horizontal parts of the I-shaped movable pulley sleeve. A sliding ring is slidably arranged in each of the first sliding grooves, and an external hanging protrusion for connecting the sliding rope is fixed on the sliding ring; two circles of second sliding clamps are provided on the vertical section of the I-shaped movable pulley sleeve, and the hollow pulley is also rotatably connected to the two second sliding clamps.

[0019] Furthermore, the pulley block is connected to two different types of sliding ropes, and there are two first types of sliding ropes, one end of which is connected to the external protrusion of the sliding ring, and the other end is connected to the first fixed columns corresponding to each other on the torsion disk, and the two first types of sliding ropes are respectively clamped in the grooves on the side walls of the torsion disk corresponding to each other;

[0020] The second type of pulley also has two ends, one end of which is connected to the hollow pulley installed on the output shaft of the torsion motor, and the other end passes around the hollow pulley installed on the corresponding movable pulley sleeve, and then passes around the hollow pulley installed on the corresponding fixed pulley sleeve, and finally fixed on the corresponding second fixed column.

[0021] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention has the following improvements:

[0022] 1. The hollow torsional shear test device for rock in the present invention aims at the problem that the current hollow torsional shear performance test of rock cannot achieve efficient and convenient measurement. The outer wall and the inner wall of the end of the sample are fixed at the same time by the inner wall fixing component structure of the sample and the outer wall fixing component of the sample, and the fixing nails can penetrate into the strong glue layer during fixing, thereby improving the reliability of the fixation of the end of the sample; in addition, the torsional force is loaded on the sample by the pulley group in conjunction with the torsional motor, and the design of the torque transmission path is combined to reduce the torque loss caused by the slight deformation of the rock sample under the action of torque, thereby improving the accuracy of applying torque to the rock sample.

[0023] 2. In the present invention, when fixing the end of the sample, the rock samples with different diameters can be clamped and fixed by moving the two symmetrically arranged sliding rods toward each other or away from each other, and the telescopic design of the support legs can adjust the distance between the upper shear fixing mechanism and the lower shear torsion mechanism, which is suitable for rock samples of different lengths; the parallel arrangement of the two sets of drive assemblies can improve the stability of the sliding rod during the sliding process, and the two sets of drive assemblies are connected by an annular toothed belt. Only one drive rod in one set of the drive assemblies needs to be rotated to achieve synchronous rotation of the two sets of drive assemblies, which is simple to operate and efficient.

[0024] 3. In the present invention, a torsional shear force is applied to the sample through the cooperation of a pulley block and a torsion motor. A fixed pulley sleeve and a hollow pulley rotatably connected thereto form a fixed pulley assembly, which can play a role in fine-tuning the torque. A movable pulley sleeve and a hollow pulley rotatably connected thereto and a sliding ring form a movable pulley assembly. The movable pulley assembly moves along the F-shaped support member, which can play an effect of amplifying the force. Under the constraint of the groove on the outer wall of the torsion disk, the slide cable can be separated from the torsion disk along the tangential direction of the groove. After the sample is angularly deformed due to the torque, the torsion disk is deformed with the sample, but the slide cable still moves away from the sample along the tangential direction of the groove. The force arm of the force applied by the slide cable will not change, and the torque applied to the sample will remain unchanged, thereby avoiding the situation where the experimental results are inaccurate due to the change in the actual torque applied to the sample after the sample is angularly deformed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the multifunctional shear testing device for rock of the present invention;

[0026] Figure 2 It is a torsional shear test device;

[0027] Figure 3 It is a schematic diagram of the rotary actuator of the present invention;

[0028] Figure 4 The energy power transmission device of the present invention;

[0029] Figure 5 The true triaxial shearing device of the present invention is Figure 1 Detailed structure diagram of the cavity interior;

[0030] Figure 6 This is a diagram of the prefabricated shape structure of the sample of the present invention;

[0031] Figure 7 This is a diagram of the structure of the sample grouping quick experiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the process flow of the multifunctional sample shearing device of the present invention;

[0033] Description of the accompanying drawings: 1. Specimen end fixing assembly; 101-octagonal plate, 1011-sliding limit through hole, 102-sliding rod, 103-clamping ring, 104-fixing nail, 105-driving rod, 106-fixing block, 107-external teeth, 108-annular toothed belt 2. Lifting cylinder; 3. Lifting cylinder; 4. Tray; 5. Fixed guide rail; 6. Upper pipe; 7. Lower pipe; 8. Torsion transmission device; 9. Pipe packaging body to be tested; 10. Dynamic workbench; 11. Vertical fixed guide rail; 12. Cylinder; 13. Linking disc; 14. Fixed pin; 15. Support rolling element; 16. Metal mesh cavity; 17. Guide plate; 18. Rotating cylinder; 19. Conveyor track; 20. Fixer; 21. Rotating small gear; 22. Rotating large gear; 23. Telescopic device; 24. Column; 25. Movable metal partition; 26. Liftable bracket; 27. Sample storage cavity DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The purpose of the present invention is to provide a true triaxial complex stress loading device capable of realizing multiple shear modes, so as to solve the problems existing in the prior art and realize the integration of multiple shear modes.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Embodiment 1

[0038] This embodiment provides a method for direct shear loading of a pipe in the circumferential direction. Figure 2 As shown, including:

[0039] Step 1: The pipe to be inspected is divided into an upper pipe 6 and a lower pipe 7 along the axial direction by an annular dividing line located on the side wall of the pipe to be inspected 9. The plane where the annular dividing line is located is perpendicular to the axis of the pipe. A first notch extending from the annular dividing line to the upper pipe 6 is provided on the side wall of the pipe to be inspected 9. A second notch extending from the annular dividing line to the lower pipe 7 is provided on the pipe to be inspected 9. The upper pipe 6 and the lower pipe 7 are connected only by the connecting portion, as shown in FIG. Figure 2 The number of connecting parts can be one or more.

[0040] Step 2: insert the mandrel into the pipe 9 to be tested and the outer wall of the mandrel is against the inner wall of the pipe 9 to be tested, so as to prevent the side wall of the pipe 9 to be tested from twisting. There may be an appropriate gap between the outer wall of the mandrel and the inner wall of the pipe 9 to be tested, so as to facilitate the insertion of the mandrel into the pipe 9 to be tested or the sleeve of the pipe 9 to be tested on the mandrel;

[0041] Step 3: One edge of the first notch is located on one side of the connecting portion along the circumferential dividing line, which is the first edge; one edge of the second notch is located on the other side of the connecting portion along the circumferential dividing line, which is the second edge; the length directions of the first edge and the second edge are respectively parallel to the axial direction of the pipe, and the pipe 9 to be tested is twisted around the axis of the pipe 9 to be tested by a twisting device; the shear surface on the twisting device 2 can abut against the first edge and the second edge and can apply opposite and circumferential twisting forces to the first edge and the second edge respectively; the twisting device is provided with a plurality of anti-deformation surfaces, each of which abuts against the remaining edges of the first notch and the second notch 1 except the first edge and the second edge;

[0042] When the solution in the first embodiment is used to twist a sample with a similar shape, the edges of the first notch and the second notch can be prevented from being deformed, so that the pipe 9 to be tested is always in a stable circumferential pure shear loading state during the torsional deformation process, which is suitable for pure shear loading experiments of thin-walled pipes or samples of similar shapes. Hyperbolic shear can also be achieved by changing the shape of the sample and the cavity.

[0043] Embodiment 2

[0044] This embodiment provides a true triaxial shearing method, such as Figures 1 to 7 As shown, including:

[0045] Step 1: Place the rock sample into a shear box and install the deformation sensor between the rock sample and the shear box;

[0046] Step 2: Place the shear box containing the rock sample into the center of the test box 27;

[0047] Step 3: Push the lateral auxiliary push-pull frame 108 away from the annular frame 106, take out the test box 27 and place it at the center of the lateral auxiliary push-pull frame 103;

[0048] Step 4: Push the lateral auxiliary push-pull frame 103 into the annular frame 104, and make the rock sample be at the geometric center of the annular frame, the center line of the upper through hole and the lower through hole of the annular frame is perpendicular to the horizontal plane; the center line of the left through hole and the right through hole of the annular frame is parallel to the horizontal plane, and the intersection of the two center lines is the geometric center point of the annular frame;

[0049] Step 5: Start the power system ( Figure 3 ), by implementing displacement control on the left cutting upward loading cylinder, the left cutting downward loading cylinder, the right cutting upward loading cylinder, the right cutting downward loading cylinder, the front side upward loading cylinder, the front side downward loading cylinder, the rear side upward loading cylinder, the rear side downward loading cylinder, the upper normal loading cylinder and the lower normal loading cylinder (controlled by the vertical fixed guide rail 11, and multiple vertical fixing devices are arranged along the ring, which can be precisely controlled), the centering clamping of the rock sample is completed;

[0050] Step 6: Start the cooling water device to circulate the cooling water in the force transfer plates of the left-cut upward loading cylinder, the left-cut downward loading cylinder, the right-cut upward loading cylinder, the right-cut downward loading cylinder, the upper normal loading cylinder and the lower normal loading cylinder (also controlled by the vertical fixed guide rail 11 respectively);

[0051] Step 7: Start the test chamber ( Figure 7 ), and preset pressure;

[0052] Step 8: Through force control, the left cutting upward loading cylinder, the left cutting downward loading cylinder, the right cutting upward loading cylinder, the right cutting downward loading cylinder, the front side upward loading cylinder, the front side downward loading cylinder, the rear side upward loading cylinder, the rear side downward loading cylinder, the upper normal loading cylinder and the lower normal loading cylinder are subjected to force control at a constant loading rate, so that the six boundary surfaces of the rock sample are in the hydrostatic pressure state of τ = σ, p = σ n Increase to normal stress σ n1 The target value of , where τ is the shear stress, σ p is the lateral stress, σ n is the normal stress;

[0053] Step 9: Servo control the upper normal loading cylinder and the lower normal loading cylinder to ensure that the normal stress remains unchanged; then, force control is performed on the left cut upward loading cylinder, the left cut downward loading cylinder, the right cut upward loading cylinder, the right cut downward loading cylinder, the front side upward loading cylinder, the front side downward loading cylinder, the rear side upward loading cylinder, and the rear side downward loading cylinder at a constant loading rate to increase the stress on the shear surface and the lateral surface to the lateral stress σ p1 Target value of

[0054] Step 10: Servo control the front upward loading cylinder, the front downward loading cylinder, the rear upward loading cylinder, the rear downward loading cylinder, the upper normal loading cylinder and the lower normal loading cylinder to ensure that the lateral stress and the normal stress remain unchanged; then, force control is performed on the left cut upward loading cylinder, the left cut downward loading cylinder, the right cut upward loading cylinder and the right cut downward loading cylinder at a constant loading rate through force control to increase the stress of the shear surface to the original rock stress τ0;

[0055] Step 11: Servo controls the front upward loading cylinder, the front downward loading cylinder, the rear upward loading cylinder, the rear downward loading cylinder, the upper normal loading cylinder and the lower normal loading cylinder to ensure that the lateral stress and the normal stress remain unchanged; at the same time, the servo controls the left downward loading cylinder and the right upward loading cylinder to ensure that the rock sample is subjected to stress in the shear direction, and the lower left section and the upper right section maintain the original rock stress τ0, and then, through displacement control, the shear force of the left upward loading cylinder and the right downward loading cylinder is increased at a constant loading rate until the residual strength is reached;

[0056] Step 12: The computer interface is connected to the force sensor 1011 and the displacement sensor 105 respectively, and the real-time signal is fed back to the computer through the force sensor and the displacement sensor, and the displacement and force value data and the macroscopic failure mode of the rock sample are recorded by the computer.

[0057] Embodiment 3

[0058] This embodiment provides a process method that combines multiple shear loading modes, such as Figure 8 As shown, including:

[0059] Step 1: Determine the specimen loading shape and loading mode, including torsional shear, triaxial shear and hyperbolic shear. Torsional shear and hyperbolic shear require the specimen to be a cylindrical specimen of 50×100mm or 25×50mm; triaxial shear requires the specimen to be a cubic specimen of 100×100×100mm.

[0060] Step 2: Conduct an experiment, select a shearing device, adjust and install the sample to conduct the experiment. The specific process is shown in Example 1 and Example 2. Compare the obtained data with the actual data to see whether it meets the expectations. If it does not meet the expectations, return to adjust the model formula and shearing mode;

[0061] Step 3: If the expected result is achieved, determine whether to repeat the experiment. If so, repeat step 2.

[0062] Step 4: If there is no need to repeat the experiment, end the experiment and analyze the data.

[0063] Step 5: Change the stress path as needed and repeat steps 1 to 5.

[0064] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A true triaxial complex stress loading device capable of realizing multiple shear modes, comprising a testing machine frame, the testing machine frame comprising columns and beams, characterized in that: A vertical actuator and an angular actuator are installed on the crossbeam. The action output end of the vertical actuator is connected to the upper pressure plate. A double shear actuator and a single shear actuator are respectively arranged on the left and right sides of the testing machine frame. The single shear actuator and the double shear actuator have different heights. The action output end of the single shear actuator is detachably connected to the dynamic workbench through a latch; the angular actuator is connected to the torsional shear transposition to realize torsional shear.

2. A true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 1, characterized in that: The pressing plate is connected with an angle actuator.

3. A true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 1, characterized in that: The maximum output force of the vertical actuator is 60MN.

4. The true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 1, characterized in that: The maximum output force of the single shear actuator is 20MN.

5. The true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 1, characterized in that: The maximum output force of the double shear actuator is 4MN.

6. The true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 2, characterized in that: The maximum output force of the rotary actuator is 1.8MN.

7. The true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 1, characterized in that: The double shear actuator is a static double shear actuator used to perform static double shear tests on rubber bearings.

8. The true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 1, characterized in that: A plurality of force sensors arranged in parallel are arranged between the action output end of the vertical actuator and the upper pressing plate.

9. The true triaxial complex stress loading device capable of realizing multiple shear modes according to claim 1, characterized in that: The angular actuator is connected to a plurality of arc-shaped (hyperbolic) shearing devices to drive them to act on the sample.

10. A true triaxial complex stress loading device capable of realizing multiple shear modes according to any one of claims 1 to 8, characterized in that: The true three-axis complex stress loading equipment that can realize multiple shear modes also includes a feeding conversion mechanism, which includes a fixed guide rail and a lifting guide rail arranged on the left and right, and the lifting guide rail is driven by the guide rail lifting mechanism. The feeding conversion mechanism also includes a feeding trolley that can be guided and moved on the fixed guide rail and the lifting guide rail. The upper side of the feeding trolley is used to place a rubber support. During the lifting process of the lifting guide rail, it rises to a high position to dock with the fixed guide rail and descends to a low position to place the feeding trolley on the dynamic workbench. The feeding conversion mechanism also includes a detachable connection structure for detachably connecting the dynamic workbench to the lower side of the feeding trolley. A support table is provided on the testing machine frame, and the bottom of the dynamic workbench and the feeding trolley both have a support matching portion for supporting and matching with the support table. The double shear actuator can move along the fixed guide rail and be fixed after moving into place. The single shear actuator is located on the right side of the double shear actuator, and the action output end of the single shear actuator is provided with a pin shaft connection structure for detachably connecting with the feeding trolley. Power can be transmitted to the torsion actuator through the transmission device in the middle of the experimental instrument to drive the arc shearing device to rotate. A cover is arranged outside the entire torsion shearing device, and a supporting cavity is arranged below the cover.

Images