Screw joint part contact stiffness modeling method based on connecting structure and machining characteristics

Abstract

The invention provides a screw joint part contact rigidity modeling method based on a connecting structure and machining characteristics, and the method comprises the steps: obtaining a three-dimensional model of a target joint part, and obtaining the contact pressure distribution data of the joint surface of a connecting piece and a connected piece in the target joint part based on the three-dimensional model and the screw pretightening force in the target joint part; the function relation between the contact pressure intensity of the joint surface of the connecting piece and the connected piece and the unit area normal rigidity is obtained, the function relation is obtained based on surface machining feature data of the joint surface, and the surface machining feature data reflect the surface appearance of the joint surface; and determining the contact stiffness of the joint surface based on the function relationship and the contact pressure distribution data. According to the technical scheme provided by the invention, the contact rigidity of the target joint part can be obtained without actual contact rigidity measurement on the target joint part, and the obtaining efficiency of the contact rigidity of the target joint part is effectively improved.

Description

Technical Field

[0001] The invention relates to the field of manufacturing technology, and in particular to a contact stiffness modeling method for a screw joint based on a connection structure and processing features. Background Art

[0002] CNC machine tools are the foundation for realizing the modernization of manufacturing technology and equipment. The whole machine system is composed of tools, spindles, columns, bed, worktable and other structures. A large number of joints are formed between the components, including a large number of fixed joints. The characteristics of the fixed joints have a direct impact on the processing performance of the machine tool. Among them, the stiffness of the fixed joints is one of the key factors affecting the deformation of the machine tool components during operation.

[0003] The majority of fixed joints in machine tools are threaded connections, mainly using screws. However, there are few studies on screw connections that are common in machine tools, and contact stiffness mainly relies on experimental measurements, which is inefficient. Summary of the invention

[0004] The present invention provides a screw joint contact stiffness modeling method based on connection structure and processing features, so as to solve the defect that the screw joint contact stiffness relies on experimental measurement in the prior art and is inefficient, thereby improving the efficiency of obtaining the screw joint contact stiffness.

[0005] The present invention provides a contact stiffness modeling method for a screw joint based on a connection structure and processing features, comprising: Acquire a three-dimensional model of a target joint portion, and acquire contact pressure distribution data of a joint surface between a connecting member and a connected member in the target joint portion based on the three-dimensional model and a screw preload in the target joint portion; Obtaining a functional relationship between the contact pressure and the normal stiffness per unit area of ​​the bonding surface of the connecting member and the connected member, wherein the functional relationship is obtained based on surface processing feature data of the bonding surface, and the surface processing feature data reflects the surface morphology of the bonding surface; Based on the functional relationship and the contact pressure distribution data, the contact stiffness of the bonding surface is determined.

[0006] According to a screw joint contact stiffness modeling method based on connection structure and processing features provided by the present invention, the contact pressure distribution data of the joint surface of the connecting member and the connected member in the target joint part is determined based on the three-dimensional model and the screw preload in the target joint part, including: Inputting the three-dimensional model into simulation software, constraining the degrees of freedom of the three-dimensional model in the simulation software based on the working condition of the target joint, and applying the preload force on the screws in the three-dimensional model; Performing model mesh division on the three-dimensional model; The contact pressure distribution data output by the simulation software is obtained.

[0007] According to a screw joint contact stiffness modeling method based on connection structure and processing features provided by the present invention, the functional relationship is: ,in, is the contact pressure on the bonding surface, is the normal stiffness per unit area on the joint surface, , is the fitting parameter.

[0008] According to a method for modeling contact stiffness of a screw joint based on a connection structure and processing features provided by the present invention, the method of obtaining a functional relationship between the contact pressure and the normal stiffness per unit area of ​​the joint surface of the connecting member and the connected member comprises: Acquiring surface topography measurement data of the bonding surface, wherein the surface topography measurement data includes density, height, and average top curvature radius of surface convexities of the bonding surface; The convex bodies within a unit area are grouped based on the height distribution characteristics of the convex bodies to obtain a plurality of convex body groups, a uniform height corresponding to each convex body group, and a convex body density of each convex body group; Setting a plurality of contact distances, and determining the contact state of the convex body group on the bonding surface at each of the contact distances based on the contact distances and the same height of the convex body group; For the convex body group that contacts each other at the contact distance, a contact area and a contact pressure are calculated based on the uniform height and the convex body density, and a contact pressure and a normal contact stiffness per unit area at the contact distance are obtained based on the contact area and the contact pressure; The contact pressure and the normal contact stiffness per unit area at each of the contact distances are fitted to obtain the functional relationship.

[0009] According to a screw joint contact stiffness modeling method based on a connection structure and processing features provided by the present invention, for the convex body group that contacts each other at the contact distance, the contact area and the contact pressure are calculated based on the uniform height and the convex body density, including: The convex body groups in contact with each other are equivalent to the contact between a sphere and a plane, and the contact area and contact pressure are calculated based on the uniform height and the convex body density; The curvature of the equivalent sphere is the sum of the curvatures of the two convex body groups in contact with each other, and the elastic modulus of the equivalent sphere conforms to the formula: , where E is the elastic modulus of the equivalent sphere, , are the Poisson's ratios of the upper and lower convex bodies in contact, are the elastic moduli of the upper and lower convex bodies in contact, respectively.

[0010] According to a screw joint contact stiffness modeling method based on connection structure and processing features provided by the present invention, the contact stiffness of the joint surface is determined based on the functional relationship and the contact pressure distribution data, including: Determining the contact pressure of the area where each node in the bonding surface is located based on the contact pressure distribution data; Determine the normal stiffness of the area where the node is located based on the functional relationship and the contact pressure of the area where each node is located; The normal stiffness of the area where each node is located is summed to obtain the contact stiffness of the joint surface.

[0011] The present invention also provides a contact stiffness modeling device for a screw joint based on a connection structure and processing features, comprising: A pressure distribution analysis module, used to obtain a three-dimensional model of a target joint, and based on the three-dimensional model and the screw preload in the target joint, obtain contact pressure distribution data of a joint surface between a connector and a connected component in the target joint; A functional relationship acquisition module, used to acquire a functional relationship between a contact pressure and a normal stiffness per unit area of ​​a bonding surface between the connector and the connected component, wherein the functional relationship is obtained based on surface processing feature data of the bonding surface, and the surface processing feature data reflects the surface morphology of the bonding surface; A contact stiffness determination module is used to determine the contact stiffness of the bonding surface based on the functional relationship and the contact pressure distribution data.

[0012] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, it implements any of the above-mentioned methods for modeling contact stiffness of screw joints based on connection structures and processing features.

[0013] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described methods for modeling contact stiffness of screw joints based on connection structures and processing features.

[0014] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the method for modeling contact stiffness of a screw joint based on a connection structure and processing features as described above is implemented.

[0015] The contact stiffness modeling method of the screw joint based on the connection structure and processing characteristics provided by the present invention obtains the surface processing feature data reflecting the surface morphology of the connecting member and the connected member in the target joint in advance, and obtains the functional relationship between the contact pressure and the normal stiffness per unit area of ​​the joint surface of the connecting member and the connected member in the target joint based on the surface processing feature data, and obtains the contact pressure distribution data of the joint surface based on the three-dimensional model of the target joint and the screw preload, and then determines the contact stiffness of the joint surface through the contact pressure distribution data and the functional relationship. The contact stiffness of the target joint can be obtained without actually measuring the contact stiffness of the target joint, which effectively improves the efficiency of obtaining the contact stiffness of the target joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a flow chart of the contact stiffness modeling method of the screw joint based on the connection structure and processing characteristics provided by the present invention.

[0018] Figure 2 It is a schematic diagram of the convex peaks of the machined surface in the contact stiffness modeling method of the screw joint based on the connection structure and the machining features provided by the present invention.

[0019] Figure 3 It is a schematic diagram of a three-dimensional surface convex body and a reference plane in the screw joint contact stiffness modeling method based on the connection structure and processing features provided by the present invention.

[0020] Figure 4 It is a schematic diagram of the contact deformation between an equivalent sphere and a plane in the contact stiffness modeling method of a screw joint based on a connection structure and processing features provided by the present invention.

[0021] Figure 5 It is a schematic diagram of the fitting process of the functional relationship in the contact stiffness modeling method of the screw joint based on the connection structure and processing characteristics provided by the present invention.

[0022] Figure 6 It is a structural schematic diagram of a screw joint contact stiffness modeling device based on a connection structure and processing features provided by the present invention.

[0023] Figure 7 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Combine the following Figure 1-Figure 5 The present invention describes a method for modeling contact stiffness of a screw joint based on a connection structure and processing features. Figure 1 As shown, the screw joint contact stiffness modeling method based on the connection structure and processing features includes the following steps: S110, obtaining a three-dimensional model of the target joint, and obtaining contact pressure distribution data of the joint surfaces of the connecting member and the connected member in the target joint based on the three-dimensional model and the screw preload in the target joint; S120, obtaining a functional relationship between a contact pressure and a normal stiffness per unit area of ​​a bonding surface of a connecting member and a connected member, wherein the functional relationship is obtained based on surface processing feature data of the bonding surface, and the surface processing feature data reflects the surface morphology of the bonding surface; S130. Determine the contact stiffness of the bonding surface based on the functional relationship and the contact pressure distribution data.

[0026] The target joint is the joint for which the contact stiffness needs to be obtained, which includes a connector, a connected part and a screw. A three-dimensional model of the target joint is established according to the actual size parameters of the target joint. Based on the three-dimensional model and the screw preload in the target joint, the contact pressure distribution data of the joint surface of the connector and the connected part in the target joint is obtained, including: The three-dimensional model is input into the simulation software, and the degrees of freedom of the three-dimensional model are constrained in the simulation software based on the working conditions of the target joint and a preload is applied to the screws in the three-dimensional model; Perform mesh division on the three-dimensional model; Get the pressure distribution data output by the simulation software.

[0027] The simulation software can be an existing software that can realize simulation analysis, such as ANSYS WORKBENCH software. In the simulation software, the material parameters of each component in the three-dimensional model are set, and the friction contact setting is adopted at the contact between the connected part and the lower surface of the screw head, and the connecting part and the connected part, and the threaded connection setting is adopted at the contact between the screw thread and the screw hole thread. For example, in the contact setting, the contact between the screw and the connected part, and the connecting part and the connected part are set to "friction", with a friction coefficient of 0.15, and the contact between the screw and the connecting part is a threaded connection, specifically, the contact type is set to "friction", with a friction coefficient of 0.15, "contact geometry correction" is "threaded connection", "direction" is "rotation axis", "starting point" is the starting contact point of each screw and the connecting part (the starting point of thread engagement), "end point" is the end contact point of each screw and the connecting part (the end point of thread engagement), "average spacing diameter" is the screw diameter, and "spacing distance" is the thread pitch.

[0028] According to the actual working conditions, the degrees of freedom of the connecting parts and the connected parts are constrained. The constraints on the connecting parts are generally fixed constraints, and the connected parts are generally not constrained. Apply axial preload force to each screw. The preload force is calculated based on the strength grade, nominal diameter and preload torque of the screw. The calculation method of the axial preload force of the screw is: ; (1) Where T is the screw preload torque and D is the screw nominal diameter.

[0029] When meshing a three-dimensional model, you can use a variety of appropriate methods and unit sizes to mesh the model. For example, the "hexahedron-dominated method" is recommended for meshing connectors and connected parts, that is, it is necessary to ensure that the mesh on the joint surface is as uniformly sized as possible. The "MultiZone" method is recommended for screws, that is, it is necessary to ensure that the "unit size" of the mesh is neither too large nor too small. It needs to be determined based on the actual size of the part and the computing power of the equipment. The recommended range is 1-3mm.

[0030] After completing the above settings in the simulation software, start the calculation, and the software will output the contact pressure distribution data of the joint surface between the connector and the connected parts in the target joint.

[0031] In the method provided by the present invention, the functional relationship between the contact pressure of the bonding surface and the normal stiffness per unit area can be obtained in advance based on the surface processing feature data of the bonding surface in the target bonding part, and then the contact stiffness of the bonding surface can be obtained based on the contact pressure distribution data and the functional relationship output by the simulation software. Specifically, the functional relationship between the contact pressure and the normal stiffness per unit area of ​​the bonding surface of the connection point and the connected part is obtained, including: Acquire surface topography measurement data of the bonding surface, wherein the surface topography measurement data includes density, height and average top curvature radius of surface convex bodies of the bonding surface; The convex bodies within a unit area are grouped based on the height distribution characteristics of the convex bodies to obtain a plurality of convex body groups, a uniform height corresponding to each convex body group, and a convex body density of each convex body group; Setting multiple contact distances, and determining the contact state of the convex body group on the bonding surface at each contact distance based on the same height of the contact distance and the convex body group; For the convex body group that contacts each other at the contact distance, the contact area and contact pressure are calculated based on the uniform height and convex body density. Based on the contact area and contact pressure, the contact pressure and normal contact stiffness per unit area at the contact distance are obtained. The contact pressure and normal contact stiffness per unit area at each contact distance are fitted to obtain a functional relationship.

[0032] like Figure 3 As shown, the material surfaces of the connecting member and the connected member are not smooth, but there are some convex bodies on the reference plane, and these convex bodies can also be called convex bodies. In the method provided by the present invention, based on the distribution characteristics of convex bodies in the surface morphology, a contact model of the bonding surface with a small area is established to obtain the functional relationship between the contact pressure and the normal contact stiffness per unit area.

[0033] like Figure 5 As shown, in the method provided by the present invention, the surface morphology measurement is first performed to obtain the three-dimensional morphology data of the bonding surface, the density, height and average top curvature radius of the surface convexities are counted and calculated, and the convexities within a unit area are grouped according to the height distribution characteristics of the convexities. The three-dimensional morphology data of the bonding surface can be obtained by measuring the surface morphology of the bonding surface in the target bonding part, or by measuring the surface morphology of the surface of a specified material. The specified material and the materials of the connector and the connected part should be produced in the same batch and have consistent surface morphology characteristics. The following is an example of measuring the surface morphology of the bonding surface of the target bonding part and the connected point to construct a functional relationship.

[0034] To measure the surface morphology of the joint surface of the fixed joint, professional measuring instruments, such as white light interferometer, are required to obtain three-dimensional surface data. The tiny protrusions on the joint surface under the surface roughness scale are called convex bodies, and the contact between the two joint surfaces is regarded as the peak-to-peak contact behavior of the convex bodies.

[0035] The density of the convex body is the number of convex bodies per unit area of ​​the machined surface. Each convex body of the machined surface corresponds to a convex peak of the surface three-dimensional data. The eight-point method is used to define the peak of the rough surface, that is, when the height value of a sampling point is greater than the height values ​​of the eight adjacent points, it is considered a peak, such as Figure 2By comparing all sampling points in the measurement area, the total number of peaks N can be obtained.

[0036] The peak density is calculated as: ; (2) In the formula, is the peak density, S is the binding surface area, and N is the total number of peaks within area S.

[0037] The height of the convex body is the vertical distance between the sampling point at the peak and the reference plane, and the calculation formula is: ; (3) In the formula, For the The height of a convex body.

[0038] The calculation formula for the average height and standard deviation of the convex body of the entire surface is: ; (4) in, is the average height of the convex body, is the height standard deviation.

[0039] The radius of curvature of a convex body is the radius of curvature at its peak. For a three-dimensional surface, the curvature of a point is equivalent to the curvature of the sampling point at , The average of the curvatures in two perpendicular directions. A sampling point on The curvature is: ; (5) in, For sampling point The curvature of , They represent the relationship between the height z of the sampling point in the x direction and the distances in the x and y directions respectively.

[0040] The radius of curvature of the convex body is the inverse of the curvature at the peak, and the calculation formula is: ; (6) in, represents the radius of curvature of the i-th convex body, Represents the curvature at the peak of the i-th convex body.

[0041] According to the Gaussian distribution characteristics of the height of the convex bodies on the machined surface, the convex bodies are grouped. The height interval of each group of convex bodies is: ; (7) Where: is the height interval, is the number of groups.

[0042] The height of each set of convex bodies is: ; (8) in, Represents the uniform height of the i-th group of convex bodies.

[0043] The density and number of convex bodies in each group are: ; (9) in, represents the density of the i-th group of convex bodies, represents the number of convex bodies in the i-th group, is the probability density of the convex body height.

[0044] Each group of convex bodies is regarded as having a uniform height. The contact distance d between the two bonding surfaces is set each time. The contact state of the convex bodies on the contact surface is determined. The normal contact pressure is calculated based on the contact state. The normal contact pressure of all groups of convex bodies involved in the contact is summed up to obtain the total normal pressure of the bonding surface when the contact distance is d. The total normal pressure is divided by the bonding surface area to obtain the contact pressure. According to the definition of normal static stiffness, the normal stiffness per unit area of ​​the bonding surface can also be calculated based on the total normal pressure of the bonding surface.

[0045] In the method provided by the present invention, the contact behavior of two convex bodies is regarded as the contact between an equivalent sphere and a plane, that is, for a group of convex bodies that contact each other at a contact distance, the contact area and contact pressure are calculated based on a uniform height and a convex body density, including: The contacting convex bodies are equivalent to the contact between a sphere and a plane, and the contact area and contact pressure are calculated based on the uniform height and convex body density. Among them, the curvature of the equivalent sphere is the sum of the curvatures of the two convex bodies in contact with each other, and the elastic modulus of the equivalent sphere conforms to the formula: , where E is the elastic modulus of the equivalent sphere, , are the Poisson's ratios of the upper and lower convex bodies in contact, are the elastic moduli of the upper and lower convex bodies in contact. Figure 4 As shown, Figure 4 This is a schematic diagram of the contact deformation between a single elastic convex body and a rigid plane. When the sphere is in the elastic deformation stage, the contact area between the two is: ; (10) In the formula, is the contact area, is the radius of the equivalent microsphere, , , are the radii of the upper and lower convex bodies, is the normal contact deformation.

[0046] The contact pressure between the microsphere and the plane is: ; (11) In the formula, is the contact pressure, is the complex elastic modulus of the equivalent microsphere, , , is the elastic modulus of the upper and lower convex bodies, , is the Poisson's ratio of the upper and lower convex bodies.

[0047] Then the average contact pressure between the microsphere and the plane is: ; (12) The elastic limit deformation can be expressed as: ; (13) In the formula, is the hardness of the material of the connected parts, is the elastic limit deformation, is the average pressure contact coefficient, , Represents the Poisson's ratio of the connected parts.

[0048] The relationship between pressure, average pressure, contact area and deformation in the elastic-plastic deformation stage is as follows: ; (14) When the deformation reaches the elastic-plastic limit, that is, the elastic-plastic limit deformation When , the microsphere begins to undergo plastic deformation. At this time, the contact area between the two is: ; (15) The contact pressure between the microsphere and the plane is: ; (16) Then the average contact pressure between the microsphere and the plane is: ; (17) Set the contact distance d between the two bonding surfaces, determine the contact state of each group of equivalent spheres on the contact surface, calculate the normal contact pressure of each group of equivalent spheres according to the contact state, sum up the normal contact pressures of all groups of equivalent spheres involved in the contact, and you can get the total normal pressure of the bonding surface when the contact distance is d; according to the definition of normal static stiffness, calculate the normal stiffness per unit area and contact pressure of the bonding surface.

[0049] The joint surface of the connector is regarded as an ideal plane. When the highest group of convex bodies on the joint surface of the connected parts begin to contact, the contact distance d=0 is defined. The group height is For a convex body, when the contact distance between the two bonding surfaces is d, there is a contact criterion: a) when When, no contact, is the height of the convex body group with the largest height; b) When When , contact begins; c) When < When , it is in the elastic deformation stage; d) When < When , it is in the elastic-plastic deformation stage; e) When It is in the plastic deformation stage.

[0050] At a certain contact distance d, the actual normal contact pressure It should be the sum of the contact pressures of all convex bodies in contact, that is: ; (18) In the formula, is the contact pressure of the i-th group of convex bodies when the contact distance between the two rough surfaces is d.

[0051] The contact distance d is increased by a convergence amount, and the above calculation is repeated to obtain a series of unit area normal stiffness and contact pressure data. The relationship between them is fitted to obtain the functional relationship between the two.

[0052] From the definition of normal contact static stiffness, we know that , then the normal static stiffness per unit area is . Normal contact stiffness per unit interface Normal contact pressure The relationship between them can be well fitted into a power function relationship: ; (19) In the formula, is the normal contact stiffness per unit area, is the normal pressure on the bonding surface, , is the fitting parameter, which represents the basic characteristic coefficient of normal stiffness per unit area of ​​the bonding surface.

[0053] According to Hertz contact theory, the relationship between tangential stiffness and normal stiffness is generally: . (20) It can be seen that the normal stiffness per unit area of ​​the joint surface is and tangential stiffness are functions of the normal surface pressure of the combined surface, while the normal and tangential basic characteristic coefficients in the formula , It is related to many factors such as the materials of the connecting parts and the connected parts, the processing methods of the joint surfaces, the surface morphology characteristics of the joint surfaces, etc., but it is unrelated to the structural dimensions of the joint. Therefore, the functional relationship can be directly applied to obtain the contact stiffness of the joint surface of the target joint by using the contact pressure distribution data of the joint surface of the target joint output by the simulation software.

[0054] Specifically, based on the functional relationship and contact pressure distribution data, the contact stiffness of the bonding surface is determined, including: Determine the contact pressure of each node in the joint surface based on the contact pressure distribution data; Based on the functional relationship and the contact pressure of the area where each node is located, the normal stiffness of the area where the node is located is determined; The normal stiffness of the area where each node is located is summed to obtain the contact stiffness of the joint surface.

[0055] The contact pressure within the joint surface of the fixed joint is not evenly distributed, but concentrated near the screw hole under the influence of the deformation of the connected parts and the connecting parts materials, showing the characteristics of concentric circles, large inside and small outside. In the method provided by the present invention, the area near each node on the joint surface of the connected parts is regarded as satisfying the pressure uniform distribution condition, and the pressure value is the contact pressure at the node. The node is the node obtained after meshing the three-dimensional model, for example, it is the vertex of each mesh. The total stiffness of the joint surface is the sum of the contact stiffness of the area near all nodes on the joint surface. The area near the node refers to the area with the node as the center and the preset area. The total stiffness of the joint surface is the sum of the contact stiffness of the area near all nodes on the joint surface, and the calculation formula is as follows: ;(twenty one) ;(twenty two) Where: For the The normal stiffness of the area near the node is For the The contact pressure at each node is For the The area of ​​the region near the node, is the total normal contact stiffness of the bonding surface.

[0056] In summary, in one embodiment of the method provided by the present invention, according to formulas (1) to (22), by performing finite element analysis on the three-dimensional model of the fixed joint, the contact pressure distribution of the joint surface is obtained; the density, height and top curvature radius of the surface convex bodies are calculated and counted using the three-dimensional morphology data of the joint surface of the connected parts; the convex bodies within a unit area are grouped according to their height distribution, and the elastic deformation limit and elastic-plastic deformation limit of each group of equivalent microspheres are calculated; the contact pressure of each group of equivalent microspheres is calculated according to their contact state, and the equivalent microspheres of all groups participating in the contact are grouped. By summing the contact pressure of the sphere, the total normal contact pressure of the joint surface when the contact distance is d can be obtained; based on the definition of normal static stiffness, the normal stiffness of the joint surface, the normal stiffness per unit area and the contact pressure can be calculated; the contact distance d is increased by a convergence amount, and the above process is repeated to obtain a series of normal stiffness and contact pressure data, and the relationship between them is fitted to obtain the functional relationship between the two, thereby obtaining the normal and tangential basic characteristic coefficients; based on the contact pressure of the joint surface and the basic characteristic coefficient of normal stiffness per unit area, the normal contact stiffness and tangential contact stiffness of the entire joint surface are calculated. In this way, the contact stiffness of the fixed joint is accurately calculated, which provides strong support for the dynamic characteristic analysis of the whole machine tool. At the same time, compared with the experimental measurement method, the efficiency of obtaining contact stiffness is greatly improved.

[0057] The following is a description of the screw joint contact stiffness modeling device based on the connection structure and processing features provided by the present invention. The screw joint contact stiffness modeling device based on the connection structure and processing features described below and the screw joint contact stiffness modeling method based on the connection structure and processing features described above can be referred to each other. Figure 6 As shown, the screw joint contact stiffness modeling device based on the connection structure and processing features provided by the present invention includes: The pressure distribution analysis module 610 is used to obtain a three-dimensional model of the target joint, and obtain contact pressure distribution data of the joint surface between the connecting member and the connected member in the target joint based on the three-dimensional model and the screw preload in the target joint; Functional relationship acquisition module 620, used to acquire the functional relationship between the contact pressure and the normal stiffness per unit area of ​​the joint surface of the connecting member and the connected member, wherein the functional relationship is obtained based on the surface processing feature data of the joint surface, and the surface processing feature data reflects the surface morphology of the joint surface; The contact stiffness determination module 630 is used to determine the contact stiffness of the joint surface based on the functional relationship and the contact pressure distribution data.

[0058] Figure 7 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 7As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730 and a communication bus 740, wherein the processor 710, the communication interface 720 and the memory 730 communicate with each other through the communication bus 740. The processor 710 may call the logic instructions in the memory 730 to execute the contact stiffness modeling method of the screw joint based on the connection structure and the processing characteristics, the method comprising: obtaining a three-dimensional model of the target joint, obtaining the contact pressure distribution data of the joint surface of the connecting member and the connected member in the target joint based on the three-dimensional model and the screw preload in the target joint; obtaining the functional relationship between the contact pressure and the normal stiffness per unit area of ​​the joint surface of the connecting member and the connected member, the functional relationship being obtained based on the surface processing feature data of the joint surface, the surface processing feature data reflecting the surface morphology of the joint surface; determining the contact stiffness of the joint surface based on the functional relationship and the contact pressure distribution data.

[0059] In addition, the logic instructions in the above-mentioned memory 730 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0060] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the contact stiffness modeling method of the screw joint based on the connection structure and processing features provided by the above-mentioned methods, and the method includes: obtaining a three-dimensional model of the target joint, and based on the three-dimensional model and the screw preload in the target joint, obtaining the contact pressure distribution data of the joint surface of the connecting part and the connected part in the target joint; obtaining the functional relationship between the contact pressure and the normal stiffness per unit area of ​​the joint surface of the connecting part and the connected part, the functional relationship is obtained based on the surface processing feature data of the joint surface, and the surface processing feature data reflects the surface morphology of the joint surface; based on the functional relationship and the contact pressure distribution data, determining the contact stiffness of the joint surface.

[0061] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the contact stiffness modeling method of a screw joint based on connection structure and processing features provided by the above-mentioned methods, the method comprising: obtaining a three-dimensional model of a target joint, and obtaining contact pressure distribution data of a joint surface between a connecting member and a connected member in the target joint based on the three-dimensional model and the screw preload in the target joint; obtaining a functional relationship between the contact pressure and the normal stiffness per unit area of ​​the joint surface between the connecting member and the connected member, the functional relationship being obtained based on surface processing feature data of the joint surface, and the surface processing feature data reflecting the surface morphology of the joint surface; and determining the contact stiffness of the joint surface based on the functional relationship and the contact pressure distribution data.

[0062] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0063] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A contact stiffness modeling method for a screw joint based on connection structure and processing features, characterized in that: include: Acquire a three-dimensional model of a target joint portion, and acquire contact pressure distribution data of a joint surface between a connecting member and a connected member in the target joint portion based on the three-dimensional model and a screw preload in the target joint portion; Obtaining a functional relationship between the contact pressure and the normal stiffness per unit area of ​​the bonding surface of the connecting member and the connected member, wherein the functional relationship is obtained based on surface processing feature data of the bonding surface, and the surface processing feature data reflects the surface morphology of the bonding surface; Based on the functional relationship and the contact pressure distribution data, the contact stiffness of the bonding surface is determined.

2. The contact stiffness modeling method for screw joints based on connection structure and processing features according to claim 1 is characterized in that: The step of determining contact pressure distribution data of a joint surface between a connecting member and a connected member in the target joint portion based on the three-dimensional model and the screw preload in the target joint portion comprises: Inputting the three-dimensional model into simulation software, constraining the degrees of freedom of the three-dimensional model in the simulation software based on the working condition of the target joint, and applying the preload force on the screws in the three-dimensional model; Performing model mesh division on the three-dimensional model; The contact pressure distribution data output by the simulation software is obtained.

3. The contact stiffness modeling method for screw joints based on connection structure and processing features according to claim 1, characterized in that: The functional relationship is: ,in, is the contact pressure on the bonding surface, is the normal stiffness per unit area on the joint surface, , is the fitting parameter.

4. The method for modeling contact stiffness of screw joints based on connection structure and processing features according to claim 1, characterized in that: The step of obtaining a functional relationship between the contact pressure and the normal stiffness per unit area of ​​the joint surface of the connecting member and the connected member includes: Acquiring surface topography measurement data of the bonding surface, wherein the surface topography measurement data includes density, height, and average top curvature radius of surface convexities of the bonding surface; The convex bodies within a unit area are grouped based on the height distribution characteristics of the convex bodies to obtain a plurality of convex body groups, a uniform height corresponding to each convex body group, and a convex body density of each convex body group; Setting a plurality of contact distances, and determining the contact state of the convex body group on the bonding surface at each of the contact distances based on the contact distances and the same height of the convex body group; For the convex body group that contacts each other at the contact distance, a contact area and a contact pressure are calculated based on the uniform height and the convex body density, and a contact pressure and a normal contact stiffness per unit area at the contact distance are obtained based on the contact area and the contact pressure; The contact pressure and the normal contact stiffness per unit area at each of the contact distances are fitted to obtain the functional relationship.

5. The method for modeling contact stiffness of screw joints based on connection structure and processing features according to claim 4, characterized in that: The step of calculating the contact area and the contact pressure of the convex body group that are in contact with each other at the contact distance based on the uniform height and the convex body density includes: The convex body groups in contact with each other are equivalent to the contact between a sphere and a plane, and the contact area and contact pressure are calculated based on the uniform height and the convex body density; The curvature of the equivalent sphere is the sum of the curvatures of the two convex body groups that are in contact with each other, and the elastic modulus of the equivalent sphere conforms to the formula: , where E is the elastic modulus of the equivalent sphere, , are the Poisson's ratios of the upper and lower convex bodies in contact, are the elastic moduli of the upper and lower convex bodies in contact, respectively.

6. The method for modeling contact stiffness of screw joints based on connection structure and processing features according to claim 1, characterized in that: The step of determining the contact stiffness of the bonding surface based on the functional relationship and the contact pressure distribution data comprises: Determining the contact pressure of the area where each node in the bonding surface is located based on the contact pressure distribution data; Determine the normal stiffness of the region where the node is located based on the functional relationship and the contact pressure of the region where each node is located; The normal stiffness of the area where each node is located is summed to obtain the contact stiffness of the joint surface.

7. A contact stiffness modeling device for a screw joint based on a connection structure and processing features, characterized in that: include: A pressure distribution analysis module, used to obtain a three-dimensional model of a target joint, and based on the three-dimensional model and the screw preload in the target joint, obtain contact pressure distribution data of a joint surface between a connector and a connected component in the target joint; A functional relationship acquisition module, used to acquire a functional relationship between a contact pressure and a normal stiffness per unit area of ​​a bonding surface between the connector and the connected component, wherein the functional relationship is obtained based on surface processing feature data of the bonding surface, and the surface processing feature data reflects the surface morphology of the bonding surface; The contact stiffness determination module is used to determine the contact stiffness of the bonding surface based on the functional relationship and the contact pressure distribution data.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the method for modeling contact stiffness of a screw joint based on a connection structure and processing features is implemented as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for modeling contact stiffness of a screw joint based on a connection structure and processing features as claimed in any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method for modeling contact stiffness of a screw joint based on a connection structure and processing features as claimed in any one of claims 1 to 6 is implemented.

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