Metal material biaxial load testing device and method

Abstract

The invention discloses a metal material biaxial load testing device and method, and relates to the field of metal sample tensile testing, the metal material biaxial load testing device comprises a cross fixed slide rail, a temperature control box, a metal sample, a fixed assembly, a tensile assembly and a transmission assembly; wherein the cross-shaped fixed sliding rail comprises two track plates, the temperature control box is arranged at the intersection of the two track plates, and avoiding openings are formed in the surfaces, in the vertical direction, of the temperature control box; the metal sample is arranged in the temperature control box, the ends of the metal sample extend out of the corresponding receding openings respectively, the fixing assembly is connected with the end, extending out of the receding openings, of the metal sample and slides on the cross-shaped fixing sliding rail, and the stretching assembly is connected with the side, away from the metal sample, of the fixing assembly and is arranged on the cross-shaped fixing sliding rail. The stretching assembly has sliding freedom in the length direction of the track plate, the transmission assembly comprises a pressure plate and a telescopic rod, one end of the telescopic rod is hinged to the face, away from the track plate, of the stretching assembly, and the other end of the telescopic rod is hinged to one face of the pressure plate. The scheme has the effect of reducing the biaxial loading cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal specimen tensile testing, in particular to a biaxial load testing device and method for metal materials. BACKGROUND

[0002] In engineering practice, mechanical parts, building components and the like often bear bi-directional stress, while the traditional uniaxial load testing can only simulate unidirectional stress, and it is difficult to restore the real working condition, so the biaxial load testing device is derived. The core function of the biaxial load testing device is to simulate the mechanical environment of the material under the action of biaxial load, accurately measure the strength, stiffness, plastic deformation and failure mode of the material, and provide key data support for engineering structure design and material performance evaluation.

[0003] The existing biaxial load testing device adopts a cross-shaped specimen with a multi-actuator cylinder loading structure, and its basic implementation mode is as follows: two or more independent actuator cylinders are connected to the X-axis and Y-axis direction clamps respectively, the clamps are fixed with the ear area of the cross-shaped specimen, and the biaxial tension is applied to the specimen by the synchronous movement of the actuator cylinders; some devices simulate the temperature environment, and a single-sided electric heating wire heating module is arranged outside the test area to roughly monitor the environmental temperature through a temperature sensor; the mechanical parameters are obtained by recording the tension value through a tension sensor installed at the clamp, the strain measurement is mainly achieved by using an extensometer, and the crack propagation observation is completed by offline photography or microscope observation after the test.

[0004] However, the existing technology has the following defects: 1. The biaxial testing device and the uniaxial testing device are independent of each other, if the testing type needs to be switched, the specimen needs to be disassembled and the whole set of clamping and loading mechanism needs to be replaced, and the purchase cost of the special biaxial loading machine is much higher than that of the uniaxial loading equipment, which is difficult for small and medium-sized laboratories to afford.

[0005] 2. When using multiple independent actuator cylinders for loading, the control delay of each actuator cylinder easily leads to the deviation of the X / Y axis loading ratio, it is difficult to accurately simulate the non-proportional biaxial stress state, and the device compatibility is poor, the switching test of uniaxial, proportional biaxial and non-proportional biaxial cannot be completed under the same clamping device, the test efficiency is low and the data consistency is poor.

[0006] 3. The existing device has insufficient ability to reproduce the engineering stress state, it can only provide simple biaxial tension, it cannot accurately match the actual stress distribution of the tested component, and the mechanical parameter acquisition is incomplete, it can only obtain the basic force-displacement curve, it is difficult to obtain the key parameters such as biaxial yield surface and multi-axial stress-strain relationship to support the establishment of high-precision constitutive model, which leads to the limitation of material performance evaluation.

[0007] 4. The existing temperature control module cannot integrate an effective temperature control system, which limits its applicability. SUMMARY

[0008] To this end, the application provides a metal material biaxial load testing device and method to solve the problem of high purchase cost of special biaxial loading machines in the prior art.

[0009] To achieve the above-mentioned purpose, the application provides the following technical solutions: In a first aspect, a metal material biaxial load testing device includes a cross fixed slide rail, a temperature control box, a metal sample, a fixing assembly, a stretching assembly, and a transmission assembly. The cross fixed slide rail includes two vertically intersecting track plates, and the two track plates intersect and pass through at the center. The temperature control box is arranged at the intersection of the two track plates, and four faces of the temperature control box in the vertical direction are each provided with an avoiding opening. The metal sample is cross-shaped and arranged in the temperature control box, with the ends respectively extending out of the corresponding avoiding openings. A plurality of long grooves are arranged on the metal sample, and a circular groove is arranged at the center, and a cross-shaped crack is arranged at the center of the circular groove. The fixing assembly is connected to one end of the metal sample extending out of the avoiding opening and slides on the cross fixed slide rail. The stretching assembly is connected to the other end of the fixing assembly away from the metal sample and arranged on the cross fixed slide rail, and the stretching assembly has a sliding degree along the length direction of the track plate. The transmission assembly includes a pressing plate and an extension rod, one end of the extension rod is hinged to the top surface of the stretching assembly, and the other end is hinged to one side of the pressing plate. The length direction of one of the track plates of the cross fixed slide rail is the X-axis direction, and the length direction of the other track plate is the Y-axis direction.

[0010] Optionally, the fixing assembly includes a fixed clamping block, a lock washer, a fixed pressing plate, and a compression screw. The side of the fixed clamping block close to the metal sample is provided with a fixed opening, and the top is provided with a mounting hole. The mounting hole and the fixed opening are in communication, and one end of the metal sample extends into the fixed opening. The lock washer is arranged on the side of the mounting hole away from the fixed opening, and a connecting hole is formed in the lock washer. The fixed pressing plate is arranged in the fixed opening and located on the metal sample. The side of the fixed pressing plate away from the metal sample is provided with a plurality of threaded grooves. One end of the compression screw passes through the connecting hole, the mounting hole, and then extends into the fixed opening, and is threadedly connected with the threaded grooves. The compression screw is used to fix the metal sample in the fixed opening.

[0011] Optionally, the stretching assembly includes a sliding block, a roller, and a tension sensor. The sliding block is arranged on the side of the fixed clamping block away from the metal sample and is slidingly connected to the track plate. The roller has at least two, and is arranged on the side of the sliding block close to the track plate in a spaced manner and is rotationally connected with the sliding block. One end of the tension sensor is connected with the sliding block, and the other end is connected with the fixed clamping block.

[0012] Optionally, the telescopic rod comprises a first rod body, a transmission shaft, an external threaded cylinder and a second rod body; one end of the first rod body is hingedly connected to one side of the pressing plate, and the other end is coaxially provided with an adjusting motor, and the driving end of the adjusting motor extends away from the first rod body; one end of the transmission shaft is coaxially connected with the driving end of the adjusting motor; the external threaded cylinder is sleeved on the transmission shaft, one end is rotationally connected with the end of the first rod body, and the other end is connected with the end of the transmission shaft away from the first rod body; one end of the second rod body is hingedly connected with the sliding block, and the other end is sleeved on the external threaded cylinder and is threadedly connected with the external threaded cylinder.

[0013] Optionally, the temperature control box comprises a lower box body, an upper box body, an upper cover plate and heating wires; the lower box body is provided with escape openings on the periphery of the four sides, and an electric plug is arranged at the top corners; the upper box body is provided with an electric socket at the bottom corners, and the electric plug is detachably connected in the electric socket; the upper cover plate is arranged on the side of the upper box body away from the lower box body; two of the four heating wires are arranged on the two vertically opposite inner walls of the lower box body, and the other two heating wires are arranged on the two vertically opposite inner walls of the upper box body; the two surfaces of the lower box body provided with the heating wires are perpendicular to the two surfaces of the upper box body provided with the heating wires.

[0014] Optionally, it further comprises a monitoring assembly, and the monitoring assembly comprises a camera and a temperature sensor; the camera is arranged on the side of the upper cover plate close to the upper box body; and the temperature sensor is arranged on one of the inner walls of the upper box body.

[0015] Optionally, the upper cover plate is made of transparent high-temperature-resistant material.

[0016] Optionally, the pressing plate is provided with a hinged seat, the top of the sliding block is provided with a hinged seat, and the two ends of the telescopic rod are respectively hingedly connected with the hinged seats.

[0017] Optionally, the hinged seat comprises a mounting plate, a support plate and a hinge shaft; the mounting plate is connected to the pressing plate and the sliding block; the two support plates are vertically arranged on the mounting plate; the hinge shaft is connected to the two support plates at both ends, and the end of the telescopic rod is rotationally connected with the hinge shaft.

[0018] In a second aspect, the application provides a metal material biaxial load testing method, which is applied to the metal material biaxial load testing device of any one of the above-mentioned embodiments, and the method comprises the following steps: Step 1: sample installation 101: measuring the size of the metal sample, mainly including the diameter of the central circular groove, the length and depth of the long groove, and the thickness of the plate; 102: Place the metal sample in the temperature control box, and the four ends of the metal sample extend from the four escape ports. First, move the two fixed clamping blocks and the slide block in the X-axis direction to the side of the metal sample. Place the metal sample on both sides of the fixed clamping block, tighten the compression screw, and then fix it by pressing the fixed tablet. Then, also operate the fixation in the Y-axis direction; 103: Adjust the metal sample to be located in the center of the temperature control box; 104: After fixing the position, close the cover plate of the temperature control box, and ensure that the camera is above the metal sample; Step 2: Biaxial proportional stretching 201: Use the temperature control box combined with heating wires as the temperature control unit to heat the cross-shaped metal sample. Monitor the temperature change in real time and feedback through the temperature sensor. The temperature control box compensates the internal temperature according to the feedback to ensure that the temperature is maintained within the required constant range; 202: The four stretching directions are connected through the telescopic rod and the pressing plate. When the stretching testing machine is compressed downward, the adjusting motor in the first rod body drives the transmission shaft to rotate, causing the connected external threaded cylinder to be forced to retract into the second rod body along the threaded direction; 203: The fixed clamping blocks in the four directions are stretched simultaneously. The tension sensor connected to the fixed clamping block monitors the tension in real time, and the stretching stops when the preset requirement is met; 204: The camera is used to observe the biaxial cracking crack path of the metal sample in real time and capture and record; Step 3: Biaxial non-proportional stretching 301: If non-proportional biaxial stretching is required, adjust the telescopic rod retraction ratio in each direction through the adjusting motor: the X-axis direction is controlled by the adjusting motor, the transmission shaft rotates to make the telescopic rod retract more and the slide block displace less, and the Y-axis direction telescopic rod retracts less and the slide block displaces more, so that the metal sample receives different proportions of tension in different directions; 302: Monitor the tension during the stretching process through the tension sensor, and stop when the requirement is met. At the same time, observe and record the cracking crack path under non-proportional stretching through the camera; Step 4: Uniaxial stretching If uniaxial stretching test is required, only need to replace the metal sample with a one-letter-shaped metal sample, and stretch the two ends of the one-letter-shaped metal sample along the X-axis or Y-axis direction; Step 5: Obtain material mechanical property parameters 501: Record the entire loading process of the metal sample through the camera, including stretching deformation, damage, and cracking, to retain data for subsequent analysis; 502: Observe the deformation law of the metal sample under different stretching states and different temperatures in real time, and obtain the force-displacement curve and strain parameters.

[0019] Optionally, the step of obtaining the force-displacement curve comprises the following steps: S1: obtaining the displacement Dx and the force Fx of the X-axis at a certain moment during the stretching process; S2: obtaining the displacement Dy and the force Fy of the Y-axis at a certain moment during the stretching process; S3: obtaining the maximum displacement Dxmax and the maximum force Fxmax of the X-axis when the metal sample is broken; S4: obtaining the maximum displacement Dymax and the maximum force Fymax of the Y-axis when the metal sample is broken; S5: drawing the force-displacement curve according to the displacement Dx, the force Fx, the displacement Dy, the force Fy, the maximum displacement Dxmax, the maximum force Fxmax, the maximum displacement Dymax and the maximum force Fymax.

[0020] Optionally, the step of obtaining the strain parameter comprises the following steps: S1: first, sticking strain gauges on the preset measurement points in the central circular groove area of the metal sample; S2: directly reading the strain ex of the X-axis and the strain ey of the Y-axis of the metal sample at the middle position under the action of the biaxial load through the strain gauges.

[0021] Compared with the prior art, the application has at least the following beneficial effects: the cross-shaped fixed sliding rail provides an integrated reference for X and Y bidirectional loading, solves the problem of independence and switching requiring disassembly and modification of the existing single and double-axis testing device, and reduces the equipment purchase and use cost; the temperature control box is adapted to the cross-shaped sample installation through the avoiding opening, and realizes the integration of the sample fixing and temperature control functions; the long groove of the cross-shaped metal sample can guide stress concentration, the circular groove further strengthens the stress concentration effect, the cross-shaped crack provides a preset starting point for crack propagation observation, and solves the problem that the existing crack observation needs to be completed offline and the data is discontinuous; the fixed assembly can not only realize firm fixing of the sample, but also can slide along the sliding rail with the stretching assembly, avoids the fixed structure hindering the stretching displacement, and ensures the loading stability; the sliding freedom of the stretching assembly cooperates with the transmission assembly, can realize X and Y bidirectional synchronous or asynchronous stretching, and solves the proportion deviation problem caused by the loading delay of the multiple actuators; the hinged design of the telescopic rod allows small angle self-adaptation, avoids additional bending moment in the force transmission process, ensures that the pulling force accurately acts on the sample in the axial direction, improves the loading force transmission efficiency, and the overall structure realizes the integration of biaxial loading, temperature control and crack observation, and provides a basis for accurately simulating the material mechanical property testing under actual working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more intuitively illustrate the prior art and the present application, nine exemplary drawings are given below. It should be understood that the specific shapes, configurations shown in the drawings should not be considered as limiting conditions for implementing the present application; for example, based on the technical concepts and exemplary drawings disclosed in the present application, those skilled in the art can easily make routine adjustments or further optimizations on the increase / decrease / assignment of certain units, specific shapes, positional relationships, connection methods, size ratio relationships, etc.

[0023] Figure 1 A perspective view of the metal material biaxial load testing device of the present application; Figure 2 An exploded view of the fixed clamping block of the metal material biaxial load testing device of the present application; Figure 3 An exploded view of the metal material biaxial load testing device of the present application without the cross-shaped fixed slide rail and transmission assembly; Figure 4 A planar sectional view of the middle extension rod of the metal material biaxial load testing device of the present application; Figure 5 A perspective view of the middle temperature control box of the metal material biaxial load testing device of the present application; Figure 6 A bottom plan view of the upper box body of the metal material biaxial load testing device of the present application; Figure 7 A perspective view of the monitoring assembly of the metal material biaxial load testing device of the present application; Figure 8 A planar top view of the metal sample of the metal material biaxial load testing device of the present application; Figure 9 A perspective view of Figure 3 An enlarged view of part A.

[0024] Explanation of reference signs: 1, cross fixed slide rail; 2, temperature control box; 201, upper cover plate; 202, upper box body; 2021, electric socket; 203, lower box body; 2031, electric plug; 2032, avoiding port; 204, heating wire; 3, fixing assembly; 301, fixed clamping block; 3011, fixed port; 3012, mounting hole; 302, compression screw; 303, lock washer; 3031, connecting hole; 304, fixed pressing piece; 3041, threaded groove; 4, stretching assembly; 401, tension sensor; 402, sliding block; 403, roller; 5, transmission assembly; 501, pressing plate; 502, telescopic rod; 5021, first rod body; 5022, adjusting motor; 5023, transmission shaft; 5024, external thread cylinder; 5025, second rod body; 6, metal sample; 601, long slot; 602, circular groove; 603, cross-shaped crack; 7, hinged seat; 701, mounting plate; 702, support plate; 703, hinged shaft; 8, monitoring assembly; 801, camera; 802, temperature sensor. DETAILED DESCRIPTION

[0025] The application will be further described in detail below with reference to the accompanying drawings.

[0026] In the description of the application: unless otherwise specified, the meaning of "a plurality of" is two or more. The terms "first", "second", "third" and the like in the present application are intended to distinguish the objects referred to, and do not have a special meaning in the technical connotation aspect (for example, it should not be understood as emphasizing importance or order, etc.). The expressions such as "include", "contain", "have" and the like also mean "not limited to" (some units, components, materials, steps, etc.).

[0027] The terms such as "upper", "lower", "left", "right", "intermediate" and the like referred to in the present application are generally used for the purpose of intuitive understanding with reference to the drawings, and are not an absolute limitation on the positional relationship in the actual product. Change of these relative positional relationships, without departing from the technical concept disclosed in the present application, is also considered within the scope of the present application.

[0028] The technical scheme of the present application will be described below with reference to the embodiments shown in the drawings: Figures 1 to 9 The technical scheme of the present application will be described below with reference to the embodiments shown in the drawings: The embodiment of the present application provides a kind of metal material biaxial load testing device, such as Figures 1-9As shown, it comprises a cross fixed slide rail 1, a temperature control box 2, a metal sample 6, a fixing assembly 3, a stretching assembly 4, a transmission assembly 5; wherein the cross fixed slide rail 1 comprises two vertically intersecting track plates, the two track plates intersect at the center and are through; the temperature control box 2 is arranged at the intersection of the two track plates, and four faces of the temperature control box 2 in the vertical direction are each provided with an avoiding port 2032; the metal sample 6 is cross-shaped, arranged in the temperature control box 2, and the ends thereof respectively extend out of the corresponding avoiding port 2032, the metal sample 6 is provided with a plurality of long grooves 601 and a circular groove 602 at the center, and the circular groove 602 is provided with a cross-shaped crack 603 at the center; the fixing assembly 3 is connected with one end of the metal sample 6 extending out of the avoiding port 2032 and slides on the cross fixed slide rail 1; the stretching assembly 4 is connected with one end of the fixing assembly 3 away from the metal sample 6 and arranged on the cross fixed slide rail 1, and the stretching assembly 4 has a sliding degree along the length direction of the track plate; the transmission assembly 5 comprises a pressing plate 501 and an extension rod 502, one end of the extension rod 502 is hinged to one side of the stretching assembly 4 away from the track plate, and the other end is hinged to one side of the pressing plate 501; wherein the length direction of one track plate of the cross fixed slide rail 1 is the X-axis direction, and the length direction of the other track plate is the Y-axis direction.

[0029] Specifically, the cross fixed slide rail 1 provides an integrated reference for X, Y bidirectional loading, solves the problem of independence and switching requiring disassembly and modification of the existing single and double-axis testing device, and reduces the equipment purchase and use cost; the temperature control box 2 is adapted to the cross-shaped sample installation through the avoiding port 2032, realizes the integration of sample fixing and temperature control functions; the long groove 601 of the cross-shaped metal sample 6 can guide stress concentration, the circular groove 602 further strengthens the stress concentration effect, and the cross-shaped crack 603 provides a preset starting point for crack propagation observation, solves the problem that the existing crack observation needs to be completed offline and the data is discontinuous; the fixing assembly 3 can not only realize firm fixing of the sample, but also slide along the slide rail with the stretching assembly 4, avoids the fixed structure hindering the stretching displacement, and ensures the loading stability; the sliding degree of the stretching assembly 4 cooperates with the transmission assembly 5, can realize X, Y bidirectional synchronous or asynchronous stretching, and solves the proportion deviation problem caused by the loading delay of the multi-actuator cylinder; the hinged design of the two ends of the extension rod 502 allows small angle self-adaptation, avoids additional bending moment in the force transmission process, ensures that the pulling force accurately acts on the sample in the axial direction, improves the loading force transmission efficiency, and the overall structure realizes the integration of biaxial loading, temperature control and crack observation, and provides a basis for accurately simulating material mechanical property testing under actual working conditions.

[0030] In the example embodiment, reference is made to Figure 2The fixed assembly 3 comprises a fixed clamping block 301, a lock washer 303, a fixed pressing plate 304 and a pressing screw 302. The fixed clamping block 301 is provided with a fixed port 3011 on the side close to the metal sample 6, and is provided with a mounting hole 3012 on the top. The mounting hole 3012 is communicated with the fixed port 3011, and one end of the metal sample 6 extends into the fixed port 3011. The lock washer 303 is arranged on the side of the mounting hole 3012 away from the fixed port 3011, and is provided with a connecting hole 3031. The fixed pressing plate 304 is arranged in the fixed port 3011 and located on the metal sample 6. The fixed pressing plate 304 is provided with a plurality of threaded grooves 3041 on the side away from the metal sample 6. One end of the pressing screw 302 extends into the fixed port 3011 through the connecting hole 3031 and the mounting hole 3012 in sequence, and is threadedly connected with the threaded grooves 3041. The pressing screw 302 is used for fixing the metal sample 6 in the fixed port 3011.

[0031] Specifically, the fixed clamping block 301 realizes positioning of the end of the sample through the fixed port 3011. The mounting hole 3012 provides an installation channel for the pressing screw 302. The communication design ensures that the screw can directly act on the fixed pressing plate 304, avoiding lateral deviation of the sample during stretching. The lock washer 303 can offset the loosening of the pressing screw 302 caused by stretching vibration, solve the problem that the existing fixed structure is easy to loosen during stretching and affects the test precision, and ensure the stability of the fixation. The fixed pressing plate 304 cooperates with the pressing screw 302 through the threaded grooves 3041, and can uniformly transmit the pressure of the screw to the surface of the sample, avoiding direct pressure injury to the surface of the metal sample 6, and the detachable design facilitates the mounting and dismounting of the sample. The threaded connection mode of the pressing screw 302 realizes detachable fixation, and the tightening force can be adjusted according to the thickness of the sample, which is suitable for different specifications of metal samples 6, solves the problems of poor universality and complicated mounting and dismounting of the existing fixed mode, improves the sample replacement efficiency, and the four-layer fixed structure cooperates to ensure the stability of the sample during stretching, avoid damage to the sample, and provide protection for the test data precision.

[0032] In the example embodiment, referring to Figure 3 The stretching assembly 4 comprises a sliding block 402, a roller 403 and a tension sensor 401. The sliding block 402 is arranged on the side of the fixed clamping block 301 away from the metal sample 6 and is slidingly connected to the track plate. The roller 403 is at least two, is arranged on the side of the sliding block 402 close to the track plate and is rotationally connected with the sliding block 402. One end of the tension sensor 401 is connected with the sliding block 402, and the other end is connected with the fixed clamping block 301.

[0033] Specifically, the slider 402 serves as a moving carrier of the stretching assembly 4, and sliding along the track plate ensures that the stretching direction is completely consistent with the X and Y axes, avoiding additional stress caused by direction deviation and improving the accuracy of the loading direction; the roller 403 converts the sliding friction between the slider 402 and the track plate into rolling friction, greatly reducing the sliding resistance, avoiding distortion of the monitoring value of the tension sensor 401 caused by excessive resistance, and solving the problem of the influence of the sliding resistance of the existing stretching assembly 4 on the loading accuracy; the tension sensor 401 is directly connected in series in the stretching force transmission path, which can monitor the instantaneous tension in the stretching process in real time. Compared with the existing indirect monitoring of the force of the chuck, the data lag is smaller and the accuracy is higher, which can provide real-time data support for precise control of the tension to reach the preset value. The overall structure realizes the cooperation of low-resistance sliding and real-time tension monitoring, which not only ensures the accuracy of the loading direction, but also can real-time feedback the tension data, solves the problems of inaccurate tension monitoring and loading control lag in the existing technology, and lays a foundation for biaxial loading proportional control.

[0034] In the example embodiment, referring to Figure 1 and Figure 4 , the telescopic rod 502 includes a first rod body 5021, a transmission shaft 5023, an outer threaded cylinder 5024, and a second rod body 5025; one end of the first rod body 5021 is hinged to one side of the pressing plate 501, and the other end is coaxially provided with an adjusting motor 5022, and the driving end of the adjusting motor 5022 is arranged in a direction away from the first rod body 5021; one end of the transmission shaft 5023 is coaxially connected with the driving end of the adjusting motor 5022; the outer threaded cylinder 5024 is sleeved on the transmission shaft 5023, one end of which is rotatably connected with the end of the first rod body 5021, and the other end is connected with the end of the transmission shaft 5023 away from the first rod body 5021; one end of the second rod body 5025 is hinged with the slider 402, and the other end is sleeved on the outer threaded cylinder 5024 and is threadedly connected with the outer threaded cylinder 5024.

[0035] Specifically, the first rod body 5021 provides a mounting carrier for the adjusting motor 5022, which is adapted to the movement of the pressing plate 501 through the hinged design of the pressing plate 501, the adjusting motor 5022 provides a precise power source for the extension and retraction of the telescopic rod 502, solves the problem of delay caused by independent driving of the existing multi-actuating cylinder, and realizes independent and precise control of a single rod body; the transmission shaft 5023 transmits the rotary motion of the adjusting motor 5022 to the external thread cylinder 5024, ensures the transmission of power without loss, and provides a basis for subsequent motion conversion; the external thread cylinder 5024 can rotate around the end of the first rod body 5021, and rotates synchronously with the transmission shaft 5023, and through the threaded structure, the rotary motion is converted into the linear motion of the second rod body 5025, realizing the controllable adjustment of the length of the telescopic rod 502; the second rod body 5025 is hinged to the sliding block 402, and the threaded connection allows the second rod body 5025 to extend and retract axially along the external thread cylinder 5024 when the external thread cylinder 5024 rotates, thereby adjusting the total length of the telescopic rod 502 and realizing the quantifiable control of the tensile force transmission. The whole is driven by electricity and threaded transmission structure, which can independently control the retraction ratio of the X, Y axial telescopic rod 502, solves the problem that the existing technology cannot accurately simulate the non-proportional biaxial stretching, and provides core power support for the simulation of different proportional biaxial stress states.

[0036] In the example embodiment, referring to Figure 5 and Figure 6 The temperature control box 2 comprises a lower box body 203, an upper box body 202, an upper cover plate 201, and heating wires 204. The lower box body 203 is provided with avoiding openings 2032 on the circumferential surface, and an electric plug 2031 is arranged at the top corners. The upper box body 202 is provided with electric plug holes 2021 at the bottom corners, and the electric plug 2031 is detachably connected in the electric plug holes 2021. The upper cover plate 201 is arranged on the side of the upper box body 202 away from the lower box body 203. Two of the four heating wires 204 are arranged on the vertically opposite inner walls of the lower box body 203, and the other two heating wires 204 are arranged on the vertically opposite inner walls of the upper box body 202. The two surfaces of the lower box body 203 provided with the heating wires 204 are perpendicular to the two surfaces of the upper box body 202 provided with the heating wires 204.

[0037] Specifically, the avoiding opening 2032 of the lower box body 203 is matched with the requirement of the end of the metal sample 6 to extend out, and the electric plug 2031 provides detachable electrical connection for the installation of the upper box body 202, which facilitates the opening and closing of the upper box body 202 to place or take out the sample, and solves the problem of complicated installation and removal of the existing temperature control box 2; the upper box body 202 is matched with the electric plug 2031 of the lower box body 203 through the electric plug hole 2021, so as to realize quick assembly and disassembly, and at the same time, to provide a power supply channel for the heating wire 204, thereby ensuring the sealing and power supply safety of the temperature control box 2; the upper cover plate 201 can seal the top of the temperature control box 2, reduce the heat loss in the box, and ensure the temperature stability, and at the same time, provide an installation carrier for the monitoring assembly 8; the four heating wires 204 heat the inside of the temperature control box 2 from four perpendicular directions of X-axis direction and Y-axis direction, so as to make the temperature field in the box evenly distributed, solve the problem of uneven temperature caused by single-side heating of the existing device, ensure the temperature consistency of each part of the metal sample 6, improve the temperature control precision, and realize detachable sealing and four-direction uniform heating of the overall structure, which not only facilitates the installation and removal of the sample, but also can accurately maintain the constant temperature in the box.

[0038] It should be noted that the lower box body 203 is provided with a power line which can be directly connected to a power supply to supply power to the heating wire 204.

[0039] In the example embodiment, referring to Figure 7 Further comprising a monitoring assembly 8, the monitoring assembly 8 comprises a camera 801 and a temperature sensor 802; wherein the camera 801 is arranged on one side of the upper cover plate 201 close to the upper box body 202; and the temperature sensor 802 is arranged on one of the inner walls of the upper box body 202.

[0040] Specifically, the camera 801 is arranged on the inner side of the upper cover plate 201 and faces the metal sample 6, which can observe the whole process of crack initiation, expansion and fracture in the central region of the sample in real time, dynamically capture the crack path, and provide real-time and complete data for crack propagation rule analysis; and the temperature sensor 802 is arranged on the inner wall of the upper box body 202, which can monitor the temperature in the temperature control box 2 in real time, and feed back the temperature data to the temperature control system of the temperature control box 2, so as to ensure that the temperature is always maintained in the constant range required by the experiment during the test process, and improve the comprehensiveness and reliability of the test data.

[0041] In the example embodiment, the upper cover plate 201 is made of transparent high-temperature-resistant material.

[0042] Specifically, the transparent material of the upper cover plate 201 ensures that the camera 801 arranged on the inner side of the upper cover plate 201 can clearly observe the crack change and deformation of the sample in the central region through the cover plate, without the need to open the cover plate for observation; and the high-temperature-resistant material makes the upper cover plate 201 adapt to the high-temperature environment of hundreds of degrees Celsius that may exist in the temperature control box 2, and avoids deformation, melting or damage of the cover plate due to high temperature.

[0043] In this embodiment, the upper cover plate 201 can be quartz glass.

[0044] In the example embodiment, referring to Figure 3 , the pressing plate 501 is provided with a hinged seat 7, the top of the sliding block 402 is provided with a hinged seat 7, and the two ends of the telescopic rod 502 are respectively hinged to the hinged seats 7.

[0045] Specifically, the hinged seat 7 provides a stable hinged fulcrum for the telescopic rod 502. Compared with directly hinging on the surface of the pressing plate 501 or the sliding block 402, the hinged seat 7 can increase the stress area, avoid damage to the pressing plate 501 or the sliding block 402 due to local stress concentration, and improve the structural carrying capacity; at the same time, the arrangement of the hinged seat 7 ensures that the telescopic rod 502 can rotate flexibly during force transmission, adapts to the relative movement of the pressing plate 501 and the sliding block 402 during stretching, avoids force transmission loss or jamming caused by angle limitation, ensures that the pulling force can be accurately transmitted to the sample along the axial direction, improves the structural stability and service life of the transmission assembly 5, and provides structural support for the accuracy of biaxial loading.

[0046] In the example embodiment, referring to Figure 9 , the hinged seat 7 includes a mounting plate 701, a support plate 702, and a hinged shaft 703; wherein the mounting plate 701 is connected to the pressing plate 501 and the sliding block 402; two support plates 702 are symmetrically arranged on the mounting plate 701; the hinged shaft 703 is connected to the two support plates 702 at both ends, and the end of the telescopic rod 502 is rotatably connected to the hinged shaft 703.

[0047] Specifically, the mounting plate 701 increases the contact area of the hinged seat 7 with the pressing plate 501 and the sliding block 402 by being connected to the pressing plate 501 and the sliding block 402, disperses the stress, avoids deformation or damage of the pressing plate 501 or the sliding block 402 due to local stress concentration, and ensures firm fixation of the hinged seat 7; the two symmetrically arranged support plates 702 provide two-point support for the hinged shaft 703, which can greatly improve the bending resistance of the hinged shaft 703 compared with single-point support, avoid bending deformation of the hinged shaft 703 caused by large tension during stretching, and ensure the stability of the hinged structure; the hinged shaft 703 is connected to the support plate 702 at both ends, and the end of the telescopic rod 502 is rotatably connected to the hinged shaft 703, which ensures that the telescopic rod 502 can rotate flexibly around the hinged shaft 703, adapts to the change of the movement posture of the pressing plate 501 and the sliding block 402 during loading, avoids loading deviation caused by poor rotation, and further ensures the reliability of the transmission assembly 5.

[0048] In some embodiments, the present application provides a metal material biaxial loading test method, which is applied to the metal material biaxial loading test device of any one of the embodiments of the present application, and the method comprises the following steps: Step 1: Sample installation 101: Size measurement of metal sample 6, mainly including the diameter of the central circular groove 602, the length and depth of the long groove 601, and the thickness of the plate; 102: Place the metal sample 6 in the temperature control box 2, with the four ends of the metal sample 6 extending from the four escape ports 2032 respectively. First, move the two fixed clamping blocks 301 and the sliding block 402 in the X-axis direction to the side of the metal sample 6, place the metal sample 6 on both sides of the fixed clamping block 301, tighten the compression screw 302, and press and fix it through the fixed pressing plate 304. Then, the same operation is performed in the Y-axis direction; 103: Adjust the metal sample 6 to be located in the center of the temperature control box 2; 104: After fixing the position, close the upper cover plate 201 of the temperature control box 2, and ensure that the camera 801 is located above the metal sample 6; Step 2: Biaxial proportional stretching 201: Use the temperature control box 2 combined with the heating wire 204 as the temperature control unit to heat the cross-shaped metal sample 6. Real-time monitor the temperature change through the temperature sensor 802 and feedback. The temperature control box 2 compensates the internal temperature according to the feedback to ensure that the temperature is maintained within the required constant range; 202: The four stretching directions are connected through the telescopic rod 502 and the pressing plate 501. When the stretching tester is compressed downward, the built-in adjustment motor 5022 in the first rod body 5021 drives the transmission shaft 5023 to rotate, causing the connected external threaded cylinder 5024 to be forced to retract into the second rod body 5025 along the threaded direction; 203: The fixed clamping blocks 301 in the four directions are stretched simultaneously. The real-time monitoring of the tension is realized through the tension sensor 401 connected with the fixed clamping block 301. The stretching is stopped after reaching the preset requirement; 204: Real-time observation of the biaxial cracking crack path of the metal sample 6 through the camera 801 and capture recording; Step 3: Biaxial non-proportional stretching 301: If non-proportional biaxial stretching is required, adjust the proportion of telescopic rod 502 retraction in each direction through the adjustment motor 5022: the X-axis direction is controlled by the adjustment motor 5022, the transmission shaft 5023 rotates to make the telescopic rod 502 retract more and the sliding block 402 displace less, and the Y-axis direction telescopic rod 502 retracts less and the sliding block 402 displaces more, so that the metal sample 6 receives different proportions of tension in different directions; 302: During the stretching process, the tension is monitored through the tension sensor 401, and the stretching is stopped after reaching the requirement. At the same time, the cracking crack path under non-proportional stretching is observed and recorded through the camera 801; Step 4: Uniaxial stretching If uniaxial stretching test is required, only need to replace the metal sample 6 with a one-letter-shaped metal sample 6, and stretch the two ends of the one-letter-shaped metal sample 6 along the X-axis or Y-axis direction. Step 5: Obtain the mechanical property parameters of the material 501: Record the tensile deformation, damage and cracking of the metal sample 6 during the entire loading process through the camera 801, and retain the data for subsequent analysis; 502: Real-time observation of the deformation law of the metal sample 6 under different tensile states and different temperatures, and obtain the force-displacement curve and strain parameters.

[0049] It should be noted that in the experimental process, the tensile testing machine, tension sensor 401, adjusting motor 5022, camera 801, temperature sensor 802, tensile testing machine and temperature control box 2 are all connected to the controller through hard-wired direct connection, and all operations during the entire experimental process are performed by the controller. Hard-wired direct connection can ensure signal synchronization and reduce delay. The brands used by the above-mentioned devices are as follows.

[0050] Device name Brand / model Controller Yutai AI-808P Tension sensor 401 BHR-4C 300kN of China Aviation Measurement Adjusting motor 5022 IS620N+MS1H series of Huichuan Camera 801 Hikvision MV-CA050-10GC Temperature sensor 802 ADAM-4018+PT100 of RENHUA Tensile testing machine MTS-C64.305 of Taixinrong In some embodiments, obtaining the force-displacement curve comprises the following steps: S1: Obtain the displacement Dx and force Fx of the metal sample 6 in the X-axis direction at a certain moment during the tensile process; S2: Obtain the displacement Dy and force Fy of the metal sample 6 in the Y-axis direction at a certain moment during the tensile process; S3: Obtain the maximum displacement Dxmax and maximum force Fxmax of the metal sample 6 in the X-axis direction when the metal sample 6 is damaged; S4: Obtain the maximum displacement Dymax and maximum force Fymax of the metal sample 6 in the Y-axis direction when the metal sample 6 is damaged; S5: Draw the force-displacement curve according to the displacement Dx, force Fx, displacement Dy, force Fy, maximum displacement Dxmax, maximum force Fxmax, maximum displacement Dymax and maximum force Fymax.

[0051] In some embodiments, obtaining the strain parameters comprises the following steps: S1: First, paste strain gauges on the preset measurement points in the central circular groove 602 area of the metal sample 6; S2: Directly read the strain ex in the X-axis direction and the strain ey in the Y-axis direction of the metal sample 6 at the middle position under the action of the biaxial load through the strain gauges.

[0052] The technical features of the above embodiments can be combined in any way (as long as the combination of these technical features does not exist contradictory), in order to make the description simple, not all possible combinations of the technical features in the above embodiments are described; these embodiments which are not explicitly written, should also be considered as the scope of the present application.

[0053] The application is described in detail above by general description and specific embodiments. It should be understood that based on the technical concept of the application, some conventional adjustments or further innovations can be made to the specific embodiments; as long as the technical concept of the application is not deviated, the technical solutions obtained by the conventional adjustments or further innovations also fall within the protection scope of the claims of the application.

Claims

1. A biaxial load testing apparatus for a metallic material, characterized by, The utility model relates to a kind of metal tensile test device, including: Cross fixed slide rail (1), including two vertically intersecting track plates, two The track plate center meets and penetrates; Temperature control box (2), be located at two The track plate meeting place, and four faces of the temperature control box (2) in vertical direction are all equipped with avoiding mouth (2032); Metal sample (6), it is cross-shaped, be located in the temperature control box (2), and end part is respectively from the avoiding mouth (2032) corresponding to stretch out, the metal sample (6) is equipped with several long slot (601), and center is equipped with circular groove (602), the circular groove (602) center is equipped with cross-shaped crack (603); Fixed assembly (3), with the metal sample (6) one end of stretch out the avoiding mouth (2032) is connected, and slide on the cross fixed slide rail (1); Stretching assembly (4), with the fixed assembly (3) one end of away from the metal sample (6) is connected, and be located on the cross fixed slide rail (1), the stretching assembly (4) can slide along the track plate length direction; Transmission assembly (5), including pressure plate (501) and telescopic rod (502), the telescopic rod (502) one end with the stretching assembly (4) top surface articulates, the other end with the pressure plate (501) one side articulates; Wherein, the cross fixed slide rail (1) one track plate length direction is X axis direction, another track plate length direction is Y axis direction.

2. The biaxial loading testing device of a metallic material according to claim 1, wherein The fixed assembly (3) includes: Fixed clamping block (301), near the metal sample (6) one side is equipped with fixed mouth (3011), and top is equipped with mounting hole (3012), the mounting hole (3012) and the fixed mouth (3011) are communicated, and one end of the metal sample (6) is inserted into the fixed mouth (3011); Lock washer (303), be located at the mounting hole (3012) away from the fixed mouth (3011) one side, the lock washer (303) is opened and is equipped with connecting hole (3031); Fixed pressing piece (304), be located in the fixed mouth (3011), and with the metal sample (6) abuts, the fixed pressing piece (304) away from the metal sample (6) one side is equipped with several threaded grooves (3041); Compression screw (302), one end is inserted into the fixed mouth (3011) after sequentially passing through connecting hole (3031), mounting hole (3012), and is threadedly connected with the threaded groove (3041), the compression screw (302) is used for fixing the metal sample (6) in the fixed mouth (3011).

3. The biaxial loading testing device of a metallic material according to claim 2, wherein The stretching assembly (4) includes: Slide block (402), be located at the fixed clamping block (301) away from the metal sample (6) one side, and slide connection is established in the track plate; Roller (403), at least two, along the sliding direction perpendicular to the slide block (402) interval be located on the slide block (402) near the track plate one side, and with the slide block (402) rotationally connected; A tension sensor (401) is connected to the slider (402) at one end and to the fixed clamping block (301) at the other end.

4. The biaxial loading testing device of a metallic material according to claim 3, wherein The telescopic rod (502) comprises: A first rod body (5021) is hingedly connected to one side of the pressing plate (501) at one end and coaxially provided with an adjusting motor (5022) at the other end, and the driving end of the adjusting motor (5022) extends away from the first rod body (5021); A transmission shaft (5023) is coaxially connected to the driving end of the adjusting motor (5022) at one end; An external threaded cylinder (5024) is sleeved on the transmission shaft (5023), rotatably connected to the end of the first rod body (5021) at one end, and connected to the end of the transmission shaft (5023) away from the first rod body (5021) at the other end; A second rod body (5025) is hingedly connected to the slider (402) at one end and sleeved on the external threaded cylinder (5024) at the other end, and threadedly connected with the external threaded cylinder (5024).

5. The biaxial loading testing apparatus of claim 1, wherein, The temperature control box (2) comprises: A lower box body (203) is provided with four escape openings (2032) on the four circumferential surfaces, and an electric plug (2031) is arranged at the top corners; An upper box body (202) is provided with an electric socket (2021) at the bottom corners, and the electric plug (2031) is detachably connected in the electric socket (2021); An upper cover plate (201) is arranged on the side of the upper box body (202) away from the lower box body (203); Four heating wires (204) are arranged on the vertically opposite inner walls of the lower box body (203) and the upper box body (202), respectively; The two surfaces of the lower box body (203) provided with the heating wires (204) are perpendicular to the two surfaces of the upper box body (202) provided with the heating wires (204).

6. The biaxial loading testing device of a metallic material according to claim 5, wherein Further comprising a monitoring assembly (8), the monitoring assembly (8) comprises: A camera (801) is arranged on the side of the upper cover plate (201) close to the upper box body (202); A temperature sensor (802) is arranged on one of the inner walls of the upper box body (202).

7. The biaxial loading testing device of a metallic material according to claim 5, wherein The upper cover plate (201) is made of transparent high-temperature-resistant material.

8. The biaxial loading testing device of a metallic material according to claim 4, wherein The pressing plate (501) is provided with a hinge seat (7), the top of the slider (402) is provided with a hinge seat (7), and the two ends of the telescopic rod (502) are hingedly connected to the hinge seats (7), respectively.

9. The biaxial loading testing device of a metallic material according to claim 8, wherein The hinge seat (7) comprises: A mounting plate (701) is connected to the pressing plate (501) and the slider (402); Two support plates (702) are symmetrically arranged on the mounting plate (701); A hinge shaft (703) is connected to the two support plates (702) at both ends, and the ends of the telescopic rod (502) are rotatably connected to the hinge shaft (703).

10. A method for testing biaxial loads on metallic materials, characterized in that, The method is applied to the metal material biaxial load testing device of any one of claims 1-9, and the method comprises the following steps: Step 1: sample installation 101: Size measurement of the metal sample (6), mainly including the diameter of the central circular groove (602), the length and depth of the long groove (601), and the thickness of the plate; 102: Place the metal sample (6) in the temperature control box (2), with the four ends of the metal sample (6) extending from the four avoiding openings (2032), first move the two fixed clamping blocks (301) and the sliding block (402) in the X-axis direction to the side of the metal sample (6), place the metal sample (6) on both sides in the fixed clamping block (301), tighten the compression screw (302), and then fix it by pressing the fixed pressing plate (304), then operate the same in the Y-axis direction; 103: Adjust the metal sample (6) to be located in the center of the temperature control box (2); 104: After fixing the position, close the cover plate (201) of the temperature control box (2), and ensure that the camera (801) is located above the metal sample (6); Step 2: Biaxial proportional stretching 201: Use the temperature control box (2) combined with the heating wire (204) as the temperature control unit to heat the cross-shaped metal sample (6); monitor the temperature change in real time through the temperature sensor (802) and feedback, and the temperature control box (2) compensates the internal temperature according to the feedback to ensure that the temperature is maintained in the constant range required by the experiment; 202: The four stretching directions are connected through the telescopic rod (502) and the pressing plate (501), when the stretching tester is compressed downward, the built-in adjusting motor (5022) in the first rod body (5021) drives the transmission shaft (5023) to rotate, making the connected external threaded cylinder (5024) forced to shrink into the second rod body (5025) along the threaded direction; 203: The fixed clamping blocks (301) in the four directions are stretched at the same time, and the tension of the stretching is monitored in real time through the tension sensor (401) connected with the fixed clamping block (301), and the stretching is stopped when the preset requirement is reached; 204: Real-time observation of the biaxial cracking crack path of the metal sample (6) through the camera (801) and capture recording; Step 3: Biaxial non-proportional stretching 301: If non-proportional biaxial stretching is required, adjust the proportion of telescopic rod (502) retraction in each direction through the adjusting motor (5022): the X-axis direction is controlled by the adjusting motor (5022), the transmission shaft (5023) rotates to make the telescopic rod (502) shrink more and the sliding block (402) displace less, and the Y-axis direction telescopic rod (502) shrinks less and the sliding block (402) displaces more, so that the metal sample (6) is subjected to different proportions of tension in different directions; 302: During the stretching process, the tension is monitored through the tension sensor (401), and the stretching is stopped when the requirement is reached, and the cracking crack path under non-proportional stretching is observed and recorded through the camera (801); Step 4: Uniaxial stretching If uniaxial stretching test is required, only the metal sample (6) is replaced by a one-letter metal sample (6), and the two ends of the one-letter metal sample (6) are fixed in the X-axis direction or Y-axis direction for stretching; Step 5: Obtain the mechanical properties of the material 501: Record the whole process of tensile deformation, damage and cracking of the metal sample (6) during the whole loading process through the camera (801), and retain the data for subsequent analysis; 502: Real-time observation of the deformation law of the metal sample (6) under different tensile states and different temperatures, and acquisition of force-displacement curve and strain parameters.

11. The method of biaxial loading testing of metallic materials according to claim 10, characterized in that, The force-displacement curve includes the following steps: S1: Obtain the displacement Dx and force Fx of the X-axis at a certain moment in the tensile process; S2: Obtain the displacement Dy and force Fy of the Y-axis at a certain moment in the tensile process; S3: Obtain the maximum displacement Dxmax and maximum force Fxmax of the X-axis when the metal sample (6) is damaged; S4: Obtain the maximum displacement Dymax and maximum force Fymax of the Y-axis when the metal sample (6) is damaged; S5: Draw the force-displacement curve according to the displacement Dx, the force Fx, the displacement Dy, the force Fy, the maximum displacement Dxmax, the maximum force Fxmax, the maximum displacement Dymax and the maximum force Fymax.

12. The method of biaxial loading testing of metallic materials according to claim 10, wherein, The strain parameters include the following steps: S1: First, paste strain gauges on the preset measurement points in the central circular groove (602) area of the metal sample (6); S2: Directly read the strain ex of the X-axis and the strain ey of the Y-axis of the metal sample (6) at the intermediate position under the action of biaxial load through the strain gauges.

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