Test device and test method for whole-process fixed-proportion multi-axis loading

Abstract

The invention provides a test device and a test method for whole-process fixed-proportion multi-axis loading, and belongs to the technical field of structural engineering tests, and the test device comprises a counter-force frame, an actuator and a load distribution mechanism; the load distribution mechanism adopts a rigid distribution body with a first stage and a second stage connected in series, and each distribution body is provided with a load input point and two load output points; the actuator is hinged with an input point of the primary rigid distribution body, and the output of the actuator is respectively transmitted to the secondary rigid distribution body and a plurality of loading points of a test piece to be tested through the first to fourth connecting rod groups, so that the load input by the single actuator is distributed to different positions of the test piece according to a set proportion. According to the invention, the load proportion of the multi-axis rod system node test piece in the whole process of elasticity, plasticity and damage can be stably maintained, so that a load-deformation whole-process curve and a failure mode under the action of a fixed-proportion multi-axis load can be completely obtained, and a reliable test means is provided for researching the bearing performance of the multi-axis rod system node.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of structural engineering test, more particularly, relates to a test device and test method for full-process proportional multi-axial loading. BACKGROUND

[0002] As a key force transmission hinge in large-span spatial grid structures, the plate-type joint connects multiple spatial members in different directions through a joint plate, and the joint area is in a complex multi-axial stress state. Therefore, accurately evaluating the multi-axial coupling mechanical properties of such multi-axial member joint specimens under a given axial force ratio is crucial to ensuring the safety of the overall structure.

[0003] Currently, the traditional method for multi-axial loading test of multi-axial member joint specimens mainly uses multiple independently controlled actuators to load each member of the joint. Although this force-controlled loading method can achieve the predetermined load ratio in the elastic stage, it is prone to loading out of control when the joint enters the plastic or near-failure stage, resulting in the load ratio between the joint members being unable to remain constant throughout the process. This technical defect makes it difficult for the test to smoothly track and obtain the load-deformation descending curve of the joint after the peak load capacity, thereby failing to fully reveal the failure mechanism and true ultimate load capacity of the joint under proportional loading throughout the process.

[0004] Therefore, there is a lack of a test device in the prior art that can ensure stable and accurate distribution and maintenance of axial load ratio among multiple members, and can achieve smooth control throughout the loading and failure process to obtain complete mechanical response curves. The development of such a test device and method for proportional multi-axial loading has great theoretical and engineering significance for in-depth study of the load-bearing performance and failure mode of multi-axial member joint specimens under complex stress states. SUMMARY

[0005] Based on the above background technology, the present application aims to solve the problem that when multiple independent actuators are used for force-controlled loading in the prior art, it is difficult to maintain stable load ratio during the nonlinear deformation stage of the test specimen, and it is not possible to smoothly control to obtain complete load-deformation curves. The core technical problem to be solved by the present application is: how to provide a mechanical displacement loading scheme based on a single actuator drive, which realizes the application of constant load ratio to multiple loading points throughout the process through a pure mechanical transmission and distribution mechanism, so as to completely obtain the mechanical property data of the test specimen from the elastic, plastic to failure throughout the process.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is to provide a test device for full-process proportional multi-axial loading, comprising a reaction frame and an actuator arranged on the reaction frame, and further comprising a load distribution mechanism. The load distribution mechanism comprises a primary rigid distribution body, a secondary rigid distribution body, a first linkage group, a second linkage group, a third linkage group, and a fourth linkage group; The primary rigid distribution body and the secondary rigid distribution body are each provided with one load input point and two load output points; The load input point of the primary rigid distribution body is hingedly connected to the output end of the actuator; One load output point of the primary rigid distribution body is connected to the load input point of the secondary rigid distribution body through the first linkage group; The other load output point of the primary rigid distribution body is connected to the first loading point of the test piece through the second linkage group; The two load output points of the secondary rigid distribution body are respectively connected to the second loading point and the third loading point of the test piece through the third linkage group and the fourth linkage group.

[0007] Further, the primary rigid distribution body and the secondary rigid distribution body are both rigid distribution beams; The length direction of the rigid distribution beam is perpendicular to the loading direction of the actuator.

[0008] Further, two oblique sliding supports are further included; Each of the oblique sliding supports comprises: a triangular support fixed to the counterforce frame, an inclined guide rail fixed to the triangular support, an inclined sliding block slidably arranged on the inclined guide rail, and an inclined ear plate assembly fixed to the inclined sliding block; The inclined ear plate assembly of one of the oblique sliding supports is hingedly connected to the first loading point and the end of the second linkage group. The inclined ear plate assembly of the other oblique sliding support is hingedly connected to the third loading point and the end of the fourth linkage group.

[0009] Further, two horizontal sliding supports are further included; The horizontal sliding support comprises: a steel beam fixed to the counterforce frame, a horizontal guide rail fixed to the steel beam, a horizontal sliding block slidably arranged on the horizontal guide rail, and a horizontal ear plate assembly fixed to the horizontal sliding block; One of the horizontal sliding supports is connected to the end of the primary rigid distribution body through a horizontal lug plate assembly, and the other horizontal sliding support is connected to the end of the secondary rigid distribution body through a horizontal lug plate assembly.

[0010] Further, the articulated connection comprises at least an end lug plate assembly arranged at the end of the primary rigid distribution body or at the end of the secondary rigid distribution body. The end lug plate assembly comprises an end plate fixedly connected to the end of the rigid distribution beam, and a lug plate fixedly arranged on the end plate.

[0011] Further, a clamping plate type clamp is arranged on the rigid distribution beam for connecting the actuator, the first connecting rod group, the second connecting rod group, the third connecting rod group and the fourth connecting rod group, respectively.

[0012] Further, the first connecting rod group, the second connecting rod group, the third connecting rod group or the fourth connecting rod group are parallel pairs of connecting rod groups. The connecting rod group comprises two parallel long strip plates, both ends of the long strip plates are arc-shaped ends, and pin hole is arranged at the arc-shaped ends.

[0013] Further, the counterforce frame is a rectangular rigid frame, comprising an upper cross beam, a lower cross beam, a left vertical column and a right vertical column. The counterforce frame is symmetrically provided with an in-plane diagonal brace in the stress plane, and is symmetrically provided with an out-of-plane diagonal brace perpendicular to the stress plane of the counterforce frame.

[0014] Compared with the prior art, the test device for full-process proportional multi-axial loading has the following beneficial effects: The test device for full-process proportional multi-axial loading realizes true full-process proportional loading. Through the unique design of the load distribution mechanism, the output load of the actuator is synchronously distributed to the multiple loading points of the test piece according to the preset mechanical proportional relationship through the primary and secondary rigid distribution bodies and multiple connecting rod groups. This process is based on the geometric and static mechanical relationship of pure mechanics, ensuring the constancy of the load proportional relationship of each loading point in the full process from the elastic stage, plastic stage to failure of the test piece. The problem of load drop and the inability to maintain constant load proportion in the nonlinear stage of the test piece in the traditional multi-actuator force control mode is solved, so that the complete load-deformation curve can be successfully obtained.

[0015] The test device for whole-process proportional multi-axial loading has good universality and adjustability. By flexibly adjusting the relative positions of the load input points and the load output points on the primary rigid distribution body and the secondary rigid distribution body, for example, by repositioning and fixing the clamping plate type clamp on the rigid distribution beam, the load proportion acting on different loading points of the test piece can be conveniently set and changed, thereby adapting to the needs of different loading conditions, and the device has strong universality.

[0016] Another technical solution adopted by the present application is a test method for whole-process proportional multi-axial loading, which adopts the test device for whole-process proportional multi-axial loading, and comprises the following steps: An assembly step of installing the test piece between the counterforce frame and the load distribution mechanism; A parameter setting step of setting the load proportion acting on the first loading point, the second loading point and the third loading point of the test piece by adjusting the relative positions of the load input points and the load output points on the primary rigid distribution body and the secondary rigid distribution body; A loading step of starting and controlling the actuator to drive displacement, so that the load distribution mechanism synchronously distributes the load applied by the actuator to the first loading point, the second loading point and the third loading point of the test piece according to the load proportion; A monitoring step of monitoring the load values of the multiple loading points of the test piece in real time during the whole loading step.

[0017] The test method for whole-process proportional multi-axial loading proposed by the present application is realized based on the foregoing test device, and the technical problems solved and the beneficial effects generated by the two are consistent, so the beneficial effects of the test method will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0019] Fig. 1 It is a structural schematic view of the test device for whole-process proportional multi-axial loading of the present application; Fig. 2 It is a structural schematic view of the counterforce frame of the present application; Fig. 3 It is a structural schematic view of the primary rigid distribution body and its connection of the present application; Fig. 4 It is a structural schematic view of the secondary rigid distribution body and its connection of the present application; Fig. 5 This is a schematic diagram of the structure of the multi-axis rod system node specimen of the present invention; Fig. 6 This is a schematic diagram of the oblique sliding support of the present invention; Fig. 7 This is a schematic diagram of the structure of the horizontal sliding support of the present invention.

[0020] In the picture: 1. Reaction frame; 1-1. Upper crossbeam; 1-2. Lower crossbeam; 1-3. Left column; 1-4. Right column; 1-5. In-plane diagonal brace; 1-6. Out-of-plane diagonal brace; 1-7. Supporting short beam; 1-8. Frame ear plate assembly; 1-9. Frame connecting rod assembly; 2. Actuator; 3. Load distribution mechanism; 3-1. Primary rigid distribution body; 3-1-1. Clamp with internal threaded plate; 3-1-2. First clamp with lug plate; 3-1-3. First end lug plate assembly; 3-2. Secondary rigid distribution body; 3-2-1. Second clamp with lug plate; 3-2-2. Second end lug plate assembly; 3-3. First link assembly; 3-4. Second link assembly; 3-5. Third link assembly; 3-6. Fourth link assembly; 4. Multi-axis linkage node specimens; 4-1. Upper right diagonal member; 4-2. Right horizontal member; 4-3. Lower right diagonal member; 4-4. Lower left diagonal member; 4-5. Left horizontal member; 4-6. Upper left diagonal member; 4-i-1, Test piece rod end and splicing plate; 4-i-2, Connecting rod; 4-i-3, Converter; 4-i-4, Spoke-type force sensor; 4-i-5, Rod end ear plate assembly; 4-7, Node plate; 5. Angled sliding support; 5-1. Tripod; 5-2. Angled guide rail; 5-3. Angled slider; 5-4. Angled ear plate assembly; 6. Horizontal sliding support; 6-1. Steel beam; 6-2. Horizontal guide rail; 6-3. Horizontal slider; 6-4. Horizontal ear plate assembly. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0022] like Figs. 1 to 7 As shown, the device mainly includes a reaction frame 1, an actuator 2, a load distribution mechanism 3, an inclined sliding support 5, and a horizontal sliding support 6.

[0023] In a preferred embodiment, the test piece is a multi-axial rod system joint test piece 4, for example a six-limb space plate joint. The test piece includes two upper and lower joint discs 4-7 and six rods 4-1, 4-2, 4-3, 4-4, 4-5, 4-6 arranged in multiple directions along the radial direction thereof. The right upper inclined rod 4-1, the right horizontal rod 4-2, and the right lower inclined rod 4-3 are selected as the loading rods, and the rod end portions thereof correspond to the first loading point, the second loading point, and the third loading point, respectively, and are connected to the inclined sliding support and the load distribution mechanism. The remaining left lower inclined rod 4-4, the left horizontal rod 4-5, and the left upper inclined rod 4-6 are fixed rods and are connected to the counterforce frame 1. The end portions of all the rods 4-1, 4-2, 4-3, 4-4, 4-5, 4-6 are sequentially provided with a connecting rod 4-i-2, a conversion piece 4-i-3, a spoke-type force sensor 4-i-4, and a rod end ear plate assembly 4-i-5 (i = 1, 2, 3, 4, 5, 6) through bolt connection, for directly monitoring the axial force borne by each rod, and providing data support for verifying the effect of the device in maintaining the constant load ratio during the entire loading process.

[0024] The counterforce frame 1 is a rectangular rigid frame composed of profiled steel. The frame includes an upper cross beam 1-1, a lower cross beam 1-2, a left vertical column 1-3, and a right vertical column 1-4. In order to ensure that the frame has sufficient rigidity and stability under complex stress, in-plane diagonal braces 1-5 are symmetrically arranged in the stress plane of the frame formed by the cross beam and the vertical column; at the same time, in the direction perpendicular to the stress plane of the frame, an out-of-plane support system is formed by symmetrically arranging out-of-plane diagonal braces 1-6 and supporting short beams 1-7 matched therewith, to prevent the frame from overturning out of plane. The counterforce frame 1 is fixed to the laboratory foundation pedestal by foundation bolts. On the upper cross beam 1-1, the lower cross beam 1-2, and the left vertical column 1-3 of the counterforce frame 1, frame ear plate assemblies 1-8 or frame connecting rod assemblies 1-9 are fixed by bolts, for hinged connection with the left lower inclined rod 4-4, the left horizontal rod 4-5, and the left upper inclined rod 4-6 of the multi-axial rod system joint test piece 4.

[0025] The actuator 2 is fixed at the right end of the right vertical column 1-4 of the counterforce frame 1, and is connected at the left end with the load distribution mechanism.

[0026] The load distribution mechanism 3 is the core of the present application, and is connected to the power output end of the actuator 2. The load distribution mechanism 3 automatically distributes the concentrated load provided by the actuator 2 to the first loading point, the second loading point, and the third loading point of the test piece according to the preset ratio. The load distribution mechanism 3 includes a primary rigid distribution body 3-1, a secondary rigid distribution body 3-2, a first connecting rod assembly 3-3, a second connecting rod assembly 3-4, a third connecting rod assembly 3-5, and a fourth connecting rod assembly 3-6.

[0027] In this embodiment, the primary rigid distribution beam 3-1 and the secondary rigid distribution beam 3-2 can be made of H-shaped steel, box beam or thick steel plate welded in length direction perpendicular to the power transmission direction of the actuator 2. Each rigid distribution beam is provided with one load input point and two load output points.

[0028] Specifically: The load input point of the primary rigid distribution beam 3-1 is connected to the output end of the actuator 2 through a pin shaft to receive the total load from the actuator 2.

[0029] One load output point of the primary rigid distribution beam 3-1 is connected to the load input point of the secondary rigid distribution beam 3-2 through the first linkage group 3-3 to transmit part of the load to the secondary rigid distribution beam 3-2.

[0030] The other load output point of the primary rigid distribution beam 3-1 is connected to the first loading point of the test piece through the second linkage group 3-4.

[0031] The two load output points of the secondary rigid distribution beam 3-2 are respectively connected to the second loading point and the third loading point of the test piece through the third linkage group 3-5 and the fourth linkage group 3-6.

[0032] Based on the principle of lever, the distribution ratio of the load on the primary rigid distribution beam 3-1 and the secondary rigid distribution beam 3-2 is determined by the relative position of the load input point and each output point on the rigid distribution beam (i.e. the length of the force arm). By adjusting the positions of these points, the load ratio finally acting on the first loading point, the second loading point and the third loading point of the test piece can be accurately set.

[0033] To ensure the axial load applied along the oblique loading rods 4-1 and 4-3 and to constrain the displacement of the vertical rod axis, the present application provides two oblique sliding supports. Two oblique sliding supports 5 are included. Each oblique sliding support 5 includes a triangular bracket 5-1 fixed to the counter-force frame 1, two oblique guide rails 5-2 arranged in parallel and fixed to the triangular bracket 5-1, four oblique sliding blocks 5-3, two by two, sleeved on the two oblique guide rails 5-2, and an oblique lug plate assembly 5-4 connected to the oblique sliding blocks 5-3 by a group of bolts. The oblique lug plate assembly 5-4 of one of the oblique sliding supports 5 is hingedly connected to the first loading point of the test piece and the end of the second connecting rod group 3-4 by a pin shaft. The oblique lug plate assembly 5-4 of the other oblique sliding support 5 is hingedly connected to the third loading point of the multi-axle rod system node test piece 4 and the end of the fourth connecting rod group 3-6 by another pin shaft. The oblique sliding support releases the constraint along the oblique guide rail direction at the loading point of the test piece, and decomposes and converts the force transmitted by the load distribution mechanism 3 into axial load applied to the corresponding rod of the multi-axle rod system node test piece 4.

[0034] To balance the gravity of the load distribution mechanism 3, the present application provides two sets of horizontal sliding supports 6. The horizontal sliding support 6 includes a steel beam 6-1 fixed to the lower cross beam 1-2 of the counter-force frame 1, a horizontal guide rail 6-2 fixed to the steel beam 6-1, a horizontal sliding block 6-3 assembled on the horizontal guide rail 6-2 and capable of sliding thereon, and a horizontal lug plate assembly 6-4 fixed to the top of the horizontal sliding block 6-3. Correspondingly, at the ends of the primary rigid distribution body 3-1 and the secondary rigid distribution body 3-2, a first end lug plate assembly 3-1-3 and a second end lug plate assembly 3-2-2 are respectively provided. The end lug plate assembly is composed of an end plate welded to the end of the rigid distribution beam, and a lug plate vertically fixed to the end plate. The horizontal lug plate assembly 6-4 is hingedly connected to the corresponding end lug plate assembly by a pin shaft, so that the load distribution mechanism 3 is supported on the horizontal sliding support 6. The horizontal sliding support 6 not only provides vertical support for the rigid distribution beam to balance its own weight, but also ensures that it can slide freely in the horizontal direction during loading, releasing the horizontal constraint caused by the deformation of the test piece.

[0035] Regarding the connection details, the primary rigid distributor 3-1 or the secondary rigid distributor 3-2 is preferably provided with a clamping plate clamp. The clamp body is composed of double-sided clamping plates and four fastening long bolts, which can be flexibly positioned and locked along the length direction of the rigid distribution beam. Specifically, the clamping plate clamp is divided into two functional types: ear plate clamping plate clamp 3-1-2 and 3-2-1: one of the clamping plates is integrated with an ear plate structure, which is used to form a hinged connection with the first to fourth connecting rod groups 3-3, 3-4, 3-5, 3-6 through a pin shaft, realizing reliable transmission of the load. The inner threaded clamping plate clamp 3-1-1: one of the clamping plates is processed with an inner threaded hole, which can be directly threaded with the output end of the actuator 2 as the load input point of the mechanism. Through the above design, the positions of the input and output points of the load on the rigid distribution beam can be adjusted steplessly, which provides a core guarantee for accurately setting and maintaining the load ratio of each loading point, thereby greatly enhancing the versatility and flexibility of the test device.

[0036] The first to fourth connecting rod groups 3-3, 3-4, 3-5, 3-6 are themselves parallel pairs of connecting rod groups that transmit axial force. Each connecting rod group includes two parallel long plates, the ends of which are processed into circular arc ends, and a pin hole is provided at the circular arc end, which realizes hinged connection with other ear plate assemblies through a pin.

[0037] Based on the same inventive concept, the test method for full-process proportional multi-axial loading using the above test device includes the following steps: 1) Assembly step: install the multi-axial link node test specimen 4 in place. The first, second, and third loading points are connected to the load distribution mechanism 3 and the corresponding inclined sliding support 5 through the second connecting rod group 3-4, the third connecting rod group 3-5, and the fourth connecting rod group 3-6, respectively.

[0038] 2) Parameter setting step: according to the target load ratio of the test, determine the force arm of the load input point and each output point on the primary rigid distributor 3-1 and the secondary rigid distributor 3-2 through calculation. Then, loosen the bolts of the clamping plate clamp, move it to the corresponding position on the rigid distribution beam, and then tighten it again, thereby completing the setting of the load ratio.

[0039] 3) Loading step: start the actuator 2 and control it to drive slowly and continuously in displacement control mode. The load output by the actuator 2 is distributed to the first, second, and third loading points of the multi-axial link node test specimen 4 through the load distribution mechanism 3 according to the pre-set load ratio relationship. In this process, from the elastic stage of the test specimen, through the plastic development stage, to the final destruction of the test specimen, the load ratio at each loading point remains constant.

[0040] 4) monitoring step: during the whole loading process, the load values of the three loading points are monitored in real time by the force sensors installed on the multi-axial rod system node specimen 4, and the deformation and strain responses of the key parts of the multi-axial rod system node specimen 4 are monitored in real time by the displacement meters or strain gauges until the complete load-deformation process curve including the descending segment is obtained.

[0041] In the description of the present application, the orientation words such as "upper", "lower", "left", "right" and the like are based on the relative positions shown in the drawings, and are only for the convenience of description, not the limitation of the actual installation position of the device.

[0042] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A test apparatus for full-process proportional multi-axial loading, comprising a counterforce frame and an actuator provided on the counterforce frame, characterized by, The load distribution mechanism further comprises a first rigid distribution body and a second rigid distribution body; The load distribution mechanism further comprises a first rigid distribution body and a second rigid distribution body; The first rigid distribution body and the second rigid distribution body are both provided with a load input point and two load output points; The load input point of the first rigid distribution body is hingedly connected to the output end of the actuator; One of the load output points of the first rigid distribution body is connected to the load input point of the second rigid distribution body through the first linkage group; The other load output point of the first rigid distribution body is connected to the first loading point of the test piece through the second linkage group; The two load output points of the second rigid distribution body are respectively connected to the second loading point and the third loading point of the test piece through the third linkage group and the fourth linkage group.

2. A testing apparatus for full process proportional multi-axial loading as claimed in claim 1, wherein, The first rigid distribution body and the second rigid distribution body are both rigid distribution beams; The length direction of the rigid distribution beam is perpendicular to the loading direction of the actuator.

3. An apparatus for full process proportional multi-axial loading as claimed in claim 2, wherein, The load distribution mechanism further comprises two oblique sliding supports; Each of the oblique sliding supports comprises: a triangular support fixed to the counterforce frame, an inclined guide rail fixed to the triangular support, an inclined sliding block slidably arranged on the inclined guide rail, and an inclined ear plate assembly fixed to the inclined sliding block; The inclined ear plate assembly of one of the oblique sliding supports is hingedly connected to the first loading point and the end of the second linkage group. The inclined ear plate assembly of the other oblique sliding support is hingedly connected to the third loading point and the end of the fourth linkage group.

4. A testing apparatus for full process proportional multi-axial loading as claimed in claim 2 or 3, wherein, The load distribution mechanism further comprises two horizontal sliding supports; Each of the horizontal sliding supports comprises: a steel beam fixed to the counterforce frame, a horizontal guide rail fixed to the steel beam, a horizontal sliding block slidably arranged on the horizontal guide rail, and a horizontal ear plate assembly fixed to the horizontal sliding block; One of the horizontal sliding supports is hingedly connected to the end of the first rigid distribution body through its horizontal ear plate assembly, and the other horizontal sliding support is hingedly connected to the end of the second rigid distribution body through its horizontal ear plate assembly.

5. An apparatus for full process proportional multi-axial loading as claimed in claim 4, wherein, The hinged connection at least comprises an end ear plate assembly arranged at the end of the first rigid distribution body or the end of the second rigid distribution body; The end ear plate assembly comprises an end plate fixedly connected to the end of the rigid distribution beam, and an ear plate fixedly arranged on the end plate.

6. A testing apparatus for full process proportional multi-axial loading as claimed in claim 2, wherein, The rigid distribution beam is provided with a clamping plate type clamp for connecting the actuator, the first linkage group, the second linkage group, the third linkage group and the fourth linkage group respectively.

7. A testing apparatus for full process proportional multi-axial loading as claimed in claim 1, wherein, The first linkage group, the second linkage group, the third linkage group or the fourth linkage group is a parallel pair of linkage groups; The linkage group comprises two parallel long strip plates, both ends of the strip plates are arc-shaped end portions, and pin hole is arranged at the arc-shaped end portions.

8. A testing apparatus for full process proportional multi-axial loading as claimed in claim 1, wherein, The counterforce frame is a rectangular rigid frame comprising an upper cross beam, a lower cross beam, a left vertical column and a right vertical column. The counter-force frame is symmetrically provided with in-plane diagonal braces in a stress plane and out-of-plane diagonal braces in a direction perpendicular to the stress plane of the counter-force frame.

9. A test method for full-scale proportional multi-axial loading using the test apparatus for full-scale proportional multi-axial loading according to any one of claims 1 to 8, characterized by, The method comprises the following steps: an assembling step of mounting the test piece between the counter-force frame and the load distribution mechanism; a parameter setting step of setting the load proportion of the first, second and third loading points of the test piece by adjusting the relative positions of the load input points and load output points on the primary and secondary rigid distribution bodies; a loading step of starting and controlling the actuator to drive displacement so that the load distribution mechanism synchronously distributes the load applied by the actuator to the first, second and third loading points of the test piece according to the load proportion; a monitoring step of monitoring the load values of the multiple loading points of the test piece in real time during the whole loading step.

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