Establishment method of equivalent spring model of 360° snap joint considering coupling effect

Abstract

The present invention discloses a method for establishing an equivalent spring model of a 360° interlocking node considering coupling effects, comprising the following steps: a. analyzing the response characteristics of the 360° interlocking nodes actually connected together under wind loads; b. decoupling the 360° interlocking nodes into an equivalent spring combination structure based on the response characteristics, and establishing an equivalent spring model considering the coupling effects; c. establishing a constitutive relationship of the equivalent spring combination structure based on the coupling effects; d. acquiring load-displacement data of the 360° interlocking nodes actually connected together through a testing device; e. analyzing the constitutive relationship of the equivalent spring combination structure in the equivalent spring model based on the load-displacement data, and acquiring the spring properties of the equivalent spring combination structure; f. inputting the spring properties of the equivalent spring into the equivalent spring model, and comparing the response results of the equivalent spring model and the 360° interlocking nodes actually connected together under wind loads to verify the validity of the equivalent spring model.

Description

Technical Field

[0001] The present invention relates to the technical field of building structure testing, and in particular to a method for establishing a 360-degree occlusal node equivalent spring model considering coupling effects. Background Art

[0002] In the construction industry, metal panels are widely used in roofs, walls and other parts due to their good aesthetics and functionality. The panels are connected by interlocking, which generally has a variety of interlocking forms, including upright lock seam interlocking structure and 360° interlocking structure. However, with the increase of wind load, the wind bearing capacity of metal panels has become a major issue.

[0003] Existing wind load-bearing capacity testing methods for 360° interlocking structures suffer from low test accuracy and complex operations, making them incapable of accurately assessing the wind resistance of metal panels. Therefore, to evaluate the wind resistance of metal panels, a three-way decoupled spring model has been proposed to simulate the mechanical behavior of the joint. This model decouples the 360° interlocking structure into three equivalent springs: horizontal, vertical, and rotational. These equivalent springs are then used to characterize the mechanical properties of the interlocking joint in these three directions. However, the existing three-way equivalent springs are relatively independent, resulting in significant discrepancies between the simulation results and the actual test results, resulting in low accuracy.

[0004] Researchers have discovered that the problem stems from a coupling effect between the three-dimensional spring stiffness of 360° interlocking metal panel nodes. For example, the coupling effect between the horizontal and rotational directions affects the mechanical properties in one direction. This means that different horizontal forces are required to produce the same horizontal displacement at different rotation angles. Therefore, a 360° interlocking node spring model that considers this spring coupling effect is needed to address this issue. However, no equivalent spring model or method for establishing it is currently available. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method for establishing a 360° bite node equivalent spring model that takes into account the coupling effect, thereby solving the problem in the prior art that the coupling effect between equivalent springs is not considered, resulting in poor bite node test results.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for establishing a 360° snap node equivalent spring model considering coupling effects includes the following steps:

[0008] a. Analyze the response characteristics of 360° interlocking nodes actually connected together under wind loads;

[0009] b. Based on the response characteristics, the 360° snap-in node is decoupled into an equivalent spring combination structure, and an equivalent spring model is established considering the coupling effect;

[0010] c. Establish the constitutive relationship of the equivalent spring combination structure based on the coupling effect;

[0011] d. Obtain load-displacement data of the actual 360° interlocking nodes connected together through the test device;

[0012] e. Analyzing the constitutive relationship of the equivalent spring combination structure in the equivalent spring model according to the load-displacement data to obtain the spring properties of the equivalent spring combination structure;

[0013] f. Input the spring properties of the equivalent spring into the equivalent spring model, and compare the response results of the equivalent spring model and the actual 360° interlocking node connected together under wind load to verify the validity of the equivalent spring model.

[0014] As an optimization, the 360° bite node includes a horizontally arranged panel, and both ends of the panel are bent and extended upward to form a first bite portion and a second bite portion;

[0015] The first engaging portion includes a first vertical plate formed by bending and extending the panel upward, a first flat plate formed by bending and extending toward a side away from the panel, a second vertical plate formed by bending and extending downward, a second flat plate formed by bending and extending toward a side close to the panel, and a third vertical plate formed by bending and extending upward. There are gaps between the first vertical plates, between the second vertical plates and the third vertical plates, and between the upper end of the third vertical plate and the first flat plate.

[0016] The second engaging portion includes a fourth vertical plate formed by bending and extending the panel upward, a third flat plate formed by bending and extending toward a side close to the panel, and a fifth vertical plate formed by bending and extending downward;

[0017] When the first engaging portion of the panel engages with the second engaging portion of the adjacent panel, the fifth vertical plate engages in the gap between the second vertical plate and the third vertical plate, the third flat plate engages in the gap between the upper end of the third vertical plate and the first flat plate, and the fourth vertical plate engages in the gap between the first vertical plate and the third vertical plate.

[0018] As an optimization, it also includes a support, which includes a horizontally arranged base plate, and a sixth vertical plate formed by bending and extending one end of the base plate upward, then bending and extending to the side away from the base plate to form a fourth flat plate, then bending and extending to form a seventh vertical plate, then bending and extending to the side close to the base plate to form a fifth flat plate, and then bending and extending upward to form an eighth vertical plate. When engaged, the eighth vertical plate is engaged between the third vertical plate and the fifth vertical plate, the seventh vertical plate is engaged between the second vertical plate and the fifth vertical plate, the sixth vertical plate is engaged between the first vertical plate and the fourth vertical plate, and the fourth flat plate is engaged between the first flat plate and the third flat plate.

[0019] As an optimization, the equivalent spring combination structure includes a multi-axis spring with two nodes and multiple degrees of freedom at the nodes, and the nodes can generate lateral displacement, vertical displacement or rotation angle under the action of force.

[0020] As an optimization, in step c,

[0021] According to the tensile constitutive relation of common metal materials, the yield function and strengthening law of the multi-axis spring are proposed and expressed as follows:

[0022]

[0023] Where f is the spring force, b1, γ1, b2, γ2 are material parameters, a0 is the initial yield surface, a1 is the maximum subsequent yield surface, m is the yield surface change rate, is the equivalent spring relative plastic displacement, where Calculated by the following formula,

[0024]

[0025] Where, is a tensor representing the relative plastic displacement in each degree of freedom;

[0026] From equations (1) and (2), it can be obtained that the constitutive relationship of the multi-axis spring when it has one degree of freedom is as follows:

[0027]

[0028] Combined with the spring displacement composition, we have:

[0029]

[0030] Where u i is the relative displacement of the spring, K i is the spring stiffness in degree of freedom i;

[0031] Substituting equations (3) and (4) into equation (5), we can obtain the displacement-force relationship of the multi-axis spring under each degree of freedom, that is,

[0032]

[0033]

[0034] Where b i and γ i Both represent the spring stiffness influence coefficients of the multi-axial spring with i degrees of freedom on the node performance, u1 and u i+1 is the relative displacement between two nodes of the multi-axial spring with corresponding degrees of freedom, f1 and f i+1 is the spring force of the multi-axis spring corresponding to the degree of freedom.

[0035] As an optimization, the testing device includes a horizontal stiffness testing device, a vertical stiffness testing device and a rotational stiffness testing device, which are respectively used to test the horizontal stiffness, vertical stiffness and rotational stiffness of the multi-axis spring.

[0036] As an optimization, the horizontal stiffness testing device includes two first clamping assemblies arranged opposite to each other, each for clamping two side panels of a 360° bite node that are bitten together;

[0037] The first clamping assembly includes a base plate and a back plate arranged in parallel with each other, the back plate is connected to the base plate by bolts, and the panel is clamped between the base plate and the back plate; the two base plates are respectively formed with clamping ends at the ends facing away from each other, which are respectively used to connect to the loading device and fix the base plate;

[0038] The loading device can drive the two first clamping components to move away from each other, causing the 360° engagement node to produce horizontal displacement, and the horizontal stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

[0039] As an optimization, the vertical stiffness test device includes a bracket with a gate-shaped structure, and an extension plate is provided at the lower end of each of the two support feet of the bracket. The two extension plates extend in a direction close to each other, and a gap is formed between the ends of the two extension plates that are close to each other; a pressure plate is provided on the lower side of the two extension plates, and the pressure plate is connected to the extension plate by bolts, and two panels of 360° bite nodes that are engaged with each other are clamped between the pressure plate and the extension plate;

[0040] A base is fixedly provided below the bracket for fixing the support, wherein the base plate of the support is fixed to the base by bolts; a clamping end is provided at the upper end of the bracket for connecting with the loading device;

[0041] The loading device can drive the bracket away from the base, causing vertical displacement between the support of the 360° interlocking node and the two interlocking panels. The vertical stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

[0042] As an optimization, the rotational stiffness testing device includes two rotating components arranged opposite to each other in an upper and lower direction, and the rotating component includes a rotating shaft, with rotating plates vertically provided at both ends of the rotating shaft, and a clamping plate installed between the same sides of the two rotating plates for clamping the panels of the 360° bite node that are bitten together; a counterweight is installed between the sides of the two rotating plates away from the clamping plate; a connecting rod is also rotatably installed on the rotating shaft, and the connecting rods of the two rotating components are respectively used to connect and fix with the loading device, and the loading device can use the connecting rod to move the two rotating shafts away from each other, so that a rotation angle is generated between the two panels of the 360° bite node that are bitten together, and the rotational stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

[0043] As an optimization, in step f, a verification device is used to test the three-way coupled deformation of the actual 360° interlocking nodes under wind load to verify the validity of the equivalent spring model;

[0044] Among them, the verification device includes a fixed seat and a simulation frame above the fixed seat. The simulation frame is a door-shaped structure, and the lower ends of its two legs are bent and extended in opposite directions to form a connecting plate. The two panels of the 360° bite node that are interlocked are connected to the connecting plate by bolts respectively. The base plate of the support of the 360° bite node is fixed on the fixed seat. The upper end of the simulation frame is connected to the loading device. The loading device can drive the simulation frame away from the fixed seat, causing the 360° bite node to produce three-way coupled deformation. The validity of the equivalent spring model is verified by the load-displacement data of the loading device.

[0045] Compared with the prior art, this application has the following beneficial effects:

[0046] This paper establishes an equivalent spring model by considering the coupling effect between the three-dimensional stiffness of the 360° interlocking joints of metal panels. It also establishes a constitutive relationship for the equivalent spring. This constitutive relationship is then analyzed using load-displacement data from a test device to obtain parameters representing the spring properties. The validity of the equivalent spring model is then verified by comparing the force applied to the joints with those at actual interlocking joints. By accounting for the coupling effect of interlocking joints, this paper achieves more accurate and precise test results for interlocking joints, enabling better evaluation of the wind resistance of metal panels and providing theoretical guidance for engineering design. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of the principle of the coupling effect between the isotropic stiffness in the present invention;

[0048] Figure 2 A model diagram of a multi-axis spring in the present invention;

[0049] Figure 3 It is a structural diagram of the horizontal stiffness testing device;

[0050] Figure 4 It is a structural diagram of the vertical stiffness testing device;

[0051] Figure 5 It is a structural diagram of the rotation stiffness testing device;

[0052] Figure 6 It is a structural diagram of the verification device;

[0053] Figure 7 : is a comparison curve between the simulation results and the test results of the equivalent spring model of the present invention;

[0054] In the figure, 1 bottom plate, 2 back plate, 3 bracket, 4 extension plate, 5 pressure plate, 6 base, 7 rotation axis, 8 rotation plate, 9 splint, 10 counterweight, 11 connecting rod, 12 fixed seat, 13 simulation frame, 14 connection plate, 15360° bite node. DETAILED DESCRIPTION

[0055] The present invention will be described in further detail below with reference to the accompanying drawings.

[0056] Specific implementation: see Figure 1-7 ,

[0057] A method for establishing a 360° snap node equivalent spring model considering coupling effects includes the following steps:

[0058] a. Analyze the response characteristics of the 360° interlocking nodes actually connected together under wind loads.

[0059] Specifically, the 360° engaging node 15 includes a horizontally arranged panel, with both ends of the panel respectively bent upward and extended to form a first engaging portion and a second engaging portion;

[0060] The first engaging portion includes a first vertical plate formed by bending and extending the panel upward, a first flat plate formed by bending and extending toward a side away from the panel, a second vertical plate formed by bending and extending downward, a second flat plate formed by bending and extending toward a side close to the panel, and a third vertical plate formed by bending and extending upward. There are gaps between the first vertical plates, between the second vertical plates and the third vertical plates, and between the upper end of the third vertical plate and the first flat plate.

[0061] The second engaging portion includes a fourth vertical plate formed by bending and extending the panel upward, a third flat plate formed by bending and extending toward a side close to the panel, and a fifth vertical plate formed by bending and extending downward;

[0062] When the first engaging portion of the panel engages with the second engaging portion of the adjacent panel, the fifth vertical plate engages in the gap between the second vertical plate and the third vertical plate, the third flat plate engages in the gap between the upper end of the third vertical plate and the first flat plate, and the fourth vertical plate engages in the gap between the first vertical plate and the third vertical plate.

[0063] It also includes a support, which includes a horizontally arranged base plate, and a sixth vertical plate formed by bending and extending one end of the base plate upward, a fourth flat plate formed by bending and extending to a side away from the base plate, a seventh vertical plate formed by bending and extending downward, a fifth flat plate formed by bending and extending to a side close to the base plate, and an eighth vertical plate formed by bending and extending upward. When engaged, the eighth vertical plate is engaged between the third and fifth vertical plates, the seventh vertical plate is engaged between the second and fifth vertical plates, the sixth vertical plate is engaged between the first and fourth vertical plates, and the fourth flat plate is engaged between the first and third flat plates.

[0064] b. Based on the response characteristics, the 360° engagement node 15 is decoupled into an equivalent spring combination structure, and an equivalent spring model is established considering the coupling effect.

[0065] Specifically, there is a coupling effect between the three-way spring stiffness of the 360° interlocking metal panel nodes, such as Figure 1 The figure shows the influence of the coupling effect between the horizontal direction and the rotation direction, that is, the horizontal force required for the node to produce the same horizontal displacement is different when the rotation angle is different.

[0066] Therefore, in the present invention, the equivalent spring combination structure includes a multi-axis spring with two nodes (I and J nodes) and multiple degrees of freedom (such as 1, 2, and 3 degrees of freedom) at the nodes, and the nodes can generate lateral displacement, vertical displacement or rotation angle under the action of force. Figure 2 As shown in the figure, compared with the existing independent triaxial spring, the coupling effect between the three-dimensional stiffness at the node can be characterized by the load-displacement constitutive relationship at the node, which makes the model simpler and the calculation more convenient.

[0067] c. Establish the constitutive relationship of the equivalent spring combination structure based on the coupling effect.

[0068] Specifically, referring to the tensile constitutive relationship of ordinary metal materials, the yield function and strengthening law of the multi-axis spring are proposed and expressed by the following formula:

[0069]

[0070] Where f is the spring force, b1, γ1, b2, γ2 are material parameters, a0 is the initial yield surface, a1 is the maximum subsequent yield surface, m is the yield surface change rate, is the equivalent spring relative plastic displacement, where Calculated by the following formula,

[0071]

[0072] Where, is a tensor representing the relative plastic displacement in each degree of freedom;

[0073] From equations (1) and (2), it can be obtained that the constitutive relationship of the multi-axis spring when it has one degree of freedom is as follows:

[0074]

[0075] Combined with the spring displacement composition, we have:

[0076]

[0077] Where u i is the relative displacement of the spring, K i is the spring stiffness in degree of freedom i;

[0078] Substituting equations (3) and (4) into equation (5), we can obtain the displacement-force relationship of the multi-axis spring under each degree of freedom, that is,

[0079]

[0080]

[0081] Where b i and γ i Both represent the spring stiffness influence coefficients of the multi-axial spring with i degrees of freedom on the node performance, u1 and u i+1 is the relative displacement between two nodes of the multi-axial spring with corresponding degrees of freedom, f1 and f i+1 is the spring force of the multi-axis spring corresponding to the degree of freedom.

[0082] At the same time, based on formula (1), the yield function of the biaxial spring (two degrees of freedom) can be simplified as follows:

[0083]

[0084] Similar to equations (1) and (2), the relationship between the node displacement u and the spring force f under each degree of freedom can be derived:

[0085]

[0086]

[0087] The common parameters a0, a1, and m in the two equations indicate a coupling relationship between the two, while the unique parameter b i , γ iRepresents the effect of the i-DOF spring on the node performance.

[0088] d. Obtain load-displacement data of the 360° interlocking nodes 15 that are actually connected together through the testing device.

[0089] Specifically, the testing device includes a horizontal stiffness testing device, a vertical stiffness testing device and a rotational stiffness testing device, which are respectively used to test the horizontal stiffness, vertical stiffness and rotational stiffness of the multi-axis spring.

[0090] The horizontal stiffness testing device comprises two first clamping assemblies arranged opposite to each other, each for clamping two side panels of a 360° snap joint 15 that are snapped together;

[0091] The first clamping assembly includes a base plate 1 and a back plate 2 arranged in parallel with each other. The back plate 2 is connected to the base plate 1 by bolts, and the panel is clamped between the base plate 1 and the back plate 2. The two ends of the base plates 1 facing away from each other are respectively formed with clamping ends, which are respectively used to connect to the loading device and fix the base plates 1.

[0092] The loading device can drive the two first clamping assemblies to move away from each other, causing the 360° engagement node 15 to produce a horizontal displacement, and the horizontal stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

[0093] The vertical stiffness testing device includes a bracket 3 with a gate-shaped structure. An extension plate 4 is provided at the lower end of each of the two supporting feet of the bracket 3. The two extension plates 4 extend toward each other, and a gap is formed between the adjacent ends of the two extension plates 4. A pressure plate 5 is provided on the lower side of the two extension plates 4. The pressure plate 5 is connected to the extension plates 4 by bolts, and two panels of 360-degree interlocking nodes 15 are clamped between the pressure plate 5 and the extension plates 4.

[0094] A base 6 is fixed below the bracket 3 for fixing the bracket, wherein the base plate of the bracket is fixed to the base 6 by bolts; a clamping end is provided at the upper end of the bracket 3 for connecting to the loading device;

[0095] The loading device can drive the bracket 3 away from the base 6, causing vertical displacement between the support of the 360° interlocking node 15 and the two interlocking panels. The vertical stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

[0096] The rotational stiffness testing device includes two rotating components arranged opposite to each other in an upper and lower direction, and the rotating component includes a rotating shaft 7, and rotating plates 8 are respectively vertically provided at both ends of the rotating shaft 7. A clamping plate 9 is installed between the same sides of the two rotating plates 8 for clamping the panels of the 360° bite node 15 that are bitten together; a counterweight 10 is installed between the two rotating plates 8 on the side away from the clamping plate 9; a connecting rod 11 is also rotatably installed on the rotating shaft 7, and the connecting rods 11 of the two rotating components are respectively used to connect and fix with the loading device. The loading device can use the connecting rod 11 to move the two rotating shafts 7 away from each other, so that a rotation angle is generated between the two panels of the 360° bite node 15 that are bitten together, and the rotational stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

[0097] e. Analyzing the constitutive relationship of the equivalent spring combination structure in the equivalent spring model according to the load-displacement data to obtain the spring properties of the equivalent spring combination structure;

[0098] Specifically, equations (6) and (7) can be used to fit the spring parameters of the triaxial spring, and equations (9) and (10) can be used to fit the spring parameters of the biaxial spring. The following spring model parameters are obtained. The least squares method can be used to fit the test data and the above equations to obtain the parameters in the table.

[0099]

[0100] f. Input the spring properties of the equivalent spring into the equivalent spring model, and compare the response results of the equivalent spring model and the actual connected 360° snap node 15 under wind load to verify the validity of the equivalent spring model.

[0101] Specifically, a verification device is used to test the three-way coupled deformation of the actual 360° interlocking nodes 15 under wind load to verify the validity of the equivalent spring model.

[0102] Among them, the verification device includes a fixed seat 12 and a simulation frame 13 above the fixed seat 12. The simulation frame 13 is a door-shaped structure, and the lower ends of its two legs are bent and extended in opposite directions to form a connecting plate 14. The two panels of the 360° bite node 15 that are bite together are connected to the connecting plate 14 by bolts respectively. The base plate of the support of the 360° bite node 15 is fixed on the fixed seat 12. The upper end of the simulation frame 13 is connected to the loading device. The loading device can drive the simulation frame 13 away from the fixed seat 12, so that the 360° bite node 15 produces three-way coupled deformation. The validity of the equivalent spring model is verified by the load-displacement data of the loading device.

[0103] The fitted spring parameters are used for finite element model simulation and compared with the test results as shown in the figure. The results show that the two have a good degree of fit, that is, the spring model can better reflect the mechanical properties of this type of panel node.

[0104] The metal panel wind resistance testing method of the present invention has the following advantages:

[0105] 1. Compared with the static wind-uplift test, this test method only needs to test the three-dimensional stiffness of the node. The test method is simple, convenient and economical.

[0106] 2. Compared with using the contact method to simulate the mechanical properties of nodes, simulation using equivalent spring parameters has higher computational efficiency.

[0107] 3. Simple operation, capable of quickly completing the testing of a large number of specimens and improving test efficiency.

[0108] 4. The implementation of automated testing reduces human errors and improves test reliability.

[0109] 5. The test device can be improved and optimized according to actual needs and has broad application prospects.

[0110] This paper establishes an equivalent spring model by considering the coupling effect between the three-dimensional stiffness of the 360° interlocking joints of metal panels. It also establishes a constitutive relationship for the equivalent spring. This constitutive relationship is then analyzed using load-displacement data from a test device to obtain parameters representing the spring properties. The validity of the equivalent spring model is then verified by comparing the force applied to the joints with those at actual interlocking joints. By accounting for the coupling effect of interlocking joints, this paper achieves more accurate and precise test results for interlocking joints, enabling better evaluation of the wind resistance of metal panels and providing theoretical guidance for engineering design.

[0111] Although the embodiments of the present invention have been shown and described, it is apparent to those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and basis of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Therefore, the embodiments of the present invention are merely illustrative examples of the present invention. No matter from which point of view, the embodiments of the present invention do not constitute a limitation on the present invention.

Claims

1. A method for establishing a 360° interlocking node equivalent spring model considering coupling effects, characterized in that: The following steps are included: a. Analyze the response characteristics of 360° interlocking nodes actually connected together under wind loads; b. Based on the response characteristics, the 360° interlocking nodes are decoupled into an equivalent spring combination structure, and an equivalent spring model is established taking into account the coupling effect; the equivalent spring combination structure includes a multi-axis spring with two nodes and multiple degrees of freedom at the nodes, wherein the nodes can generate lateral displacement, vertical displacement, or rotation angle under the action of force; c. Establish the constitutive relationship of the equivalent spring combination structure based on the coupling effect; According to the tensile constitutive relation of common metal materials, the yield function and strengthening law of the multi-axis spring are proposed and expressed as follows: Where f is the spring force, b1, γ1, b2, γ2 are material parameters, a0 is the initial yield surface, a1 is the maximum subsequent yield surface, m is the yield surface change rate, is the equivalent spring relative plastic displacement, where Calculated by the following formula, Where, is a tensor representing the relative plastic displacement in each degree of freedom; From equations (1) and (2), it can be obtained that the constitutive relationship of the multi-axis spring when it has one degree of freedom is as follows: Combined with the spring displacement composition, we have: Where u i is the relative displacement of the spring, K i is the spring stiffness in degree of freedom i; Substituting equations (3) and (4) into equation (5), we can obtain the displacement-force relationship of the multi-axis spring under each degree of freedom, that is, Where b i and γ i Both represent the spring stiffness influence coefficients of the multi-axial spring with i degrees of freedom on the node performance, u1 and u t+1 is the relative displacement between two nodes of the multi-axial spring with corresponding degrees of freedom, f1 and f i+1 is the spring force of the multi-axis spring corresponding to the degree of freedom; d. Obtaining load-displacement data of the 360° interlocking nodes actually connected together using a testing device; the testing device includes a horizontal stiffness testing device, a vertical stiffness testing device, and a rotational stiffness testing device, respectively used to test the horizontal stiffness, vertical stiffness, and rotational stiffness of the multi-axis spring; e. Analyzing the constitutive relationship of the equivalent spring combination structure in the equivalent spring model according to the load-displacement data to obtain the spring properties of the equivalent spring combination structure; f. Input the spring properties of the equivalent spring into the equivalent spring model, and compare the response results of the equivalent spring model and the actual 360° interlocking node connected together under wind load to verify the validity of the equivalent spring model.

2. The method for establishing a 360° interlocking node equivalent spring model considering coupling effect according to claim 1 is characterized in that: The 360° interlocking node comprises a horizontally arranged panel, with both ends of the panel respectively bent upward and extended to form a first interlocking portion and a second interlocking portion; The first engaging portion includes a first vertical plate formed by bending and extending the panel upward, a first flat plate formed by bending and extending toward a side away from the panel, a second vertical plate formed by bending and extending downward, a second flat plate formed by bending and extending toward a side close to the panel, and a third vertical plate formed by bending and extending upward. There are gaps between the first vertical plates, between the second vertical plates and the third vertical plates, and between the upper end of the third vertical plate and the first flat plate. The second engaging portion includes a fourth vertical plate formed by bending and extending the panel upward, a third flat plate formed by bending and extending toward a side close to the panel, and a fifth vertical plate formed by bending and extending downward; When the first engaging portion of the panel engages with the second engaging portion of the adjacent panel, the fifth vertical plate engages in the gap between the second vertical plate and the third vertical plate, the third flat plate engages in the gap between the upper end of the third vertical plate and the first flat plate, and the fourth vertical plate engages in the gap between the first vertical plate and the third vertical plate.

3. The method for establishing a 360° interlocking node equivalent spring model considering coupling effects according to claim 2, characterized in that: It also includes a support, which includes a horizontally arranged base plate, and a sixth vertical plate formed by bending and extending one end of the base plate upward, a fourth flat plate formed by bending and extending to a side away from the base plate, a seventh vertical plate formed by bending and extending downward, a fifth flat plate formed by bending and extending to a side close to the base plate, and an eighth vertical plate formed by bending and extending upward. When engaged, the eighth vertical plate is engaged between the third and fifth vertical plates, the seventh vertical plate is engaged between the second and fifth vertical plates, the sixth vertical plate is engaged between the first and fourth vertical plates, and the fourth flat plate is engaged between the first and third flat plates.

4. The method for establishing a 360° interlocking node equivalent spring model considering coupling effects according to claim 1, characterized in that: The horizontal stiffness testing device comprises two first clamping assemblies arranged opposite to each other, each for clamping two side panels of a 360° bite node that are bitten together; The first clamping assembly includes a base plate and a back plate arranged in parallel with each other, the back plate is connected to the base plate by bolts, and the panel is clamped between the base plate and the back plate; the two base plates are respectively formed with clamping ends at the ends facing away from each other, which are respectively used to connect to the loading device and fix the base plate; The loading device can drive the two first clamping components to move away from each other, causing the 360° engagement node to produce horizontal displacement, and the horizontal stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

5. The method for establishing a 360° interlocking node equivalent spring model considering coupling effects according to claim 1, characterized in that: The vertical stiffness testing device includes a bracket with a gate-shaped structure, wherein an extension plate is provided at the lower end of each of the two supporting feet of the bracket, and the two extension plates extend in a direction toward each other, with a gap between the ends of the two extension plates that are close to each other; a pressure plate is provided on the lower side of the two extension plates, and the pressure plate is connected to the extension plates by bolts, and two panels with 360-degree interlocking nodes that are interlocked together are clamped between the pressure plate and the extension plates; A base is fixedly provided below the bracket for fixing the support, wherein the base plate of the support is fixed to the base by bolts; a clamping end is provided at the upper end of the bracket for connecting with the loading device; The loading device can drive the bracket away from the base, causing vertical displacement between the support of the 360° interlocking node and the two interlocking panels. The vertical stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

6. The method for establishing a 360° interlocking node equivalent spring model considering coupling effects according to claim 1, characterized in that: The rotational stiffness testing device includes two rotating components arranged opposite to each other in an upper and lower direction, and the rotating components include a rotating shaft, with rotating plates vertically provided at both ends of the rotating shaft, and a clamping plate installed between the same sides of the two rotating plates for clamping the panels of the 360° interlocking node that are interlocked together; a counterweight is installed between the two rotating plates on the side away from the clamping plate; a connecting rod is also rotatably installed on the rotating shaft, and the connecting rods of the two rotating components are respectively used to connect and fix with the loading device. The loading device can use the connecting rod to move the two rotating shafts away from each other, so that a rotation angle is generated between the two panels of the 360° interlocking node that are interlocked together, and the rotational stiffness of the multi-axis spring is obtained through the load-displacement data of the loading device.

7. The method for establishing a 360° interlocking node equivalent spring model considering coupling effects according to claim 1, characterized in that: In step f, a verification device is used to test the three-way coupled deformation of the actual 360° interlocking nodes under wind load to verify the validity of the equivalent spring model; Among them, the verification device includes a fixed seat and a simulation frame above the fixed seat. The simulation frame is a door-shaped structure, and the lower ends of its two legs are bent and extended in opposite directions to form a connecting plate. The two panels of the 360° bite node that are interlocked are connected to the connecting plate by bolts respectively. The base plate of the support of the 360° bite node is fixed on the fixed seat. The upper end of the simulation frame is connected to the loading device. The loading device can drive the simulation frame away from the fixed seat, causing the 360° bite node to produce three-way coupled deformation. The validity of the equivalent spring model is verified by the load-displacement data of the loading device.

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