Automatic modeling method for simulating bolt connection through ABAQUS spring element

Abstract

The invention belongs to the technical field of electrical data processing, and particularly relates to an ABAQUS spring element simulated bolt connection automatic modeling method, which comprises the following steps: S1, importing an external assembly body model, and searching to obtain hole surfaces of all parts of the assembly body model; s2, acquiring a vertex corresponding to each hole surface, establishing association between the hole surfaces and the vertexes, and establishing a searched group by using all the vertexes; s3, taking one group of vertexes in the searched group as searching vertexes, and rejecting the searching vertexes in the searched group to form a new searched group; the BoundingCylinder of the hole surface associated with the searching vertex is translated in the axial direction of the hole, and a new BoundingCylinder is formed; s4, searching a vertex in the searched group through a new BoundingCylinder, and when the vertex exists, establishing hole pair information in a manner that the hole surface associated with the searched vertex and the hole surface associated with the searched vertex are grouped in pairs; and S5, creating a rigid body element and a spring element based on the hole pair information.

Description

Technical Field

[0001] The present application belongs to the technical field of electrical data processing, and in particular relates to an automatic modeling method for simulating bolt connections using an ABAQUS spring element. Background Art

[0002] The joint and the support are usually connected by bolts, which are usually subjected to tension, shear or a combination of tension and shear. When performing strength analysis on joint parts, in order to simulate the accurate working conditions of the joint, it is necessary to perform finite element simulation on multiple bolt connections. At least two stiffnesses of the bolt in the shear direction and one stiffness in the tensile direction should be defined. If necessary, a local coordinate system should be defined to ensure that the force direction of the spring element is the same as the actual force direction of the bolt.

[0003] Bolt connections are divided into two categories, lap bolt connections and symmetrical bolt connections. For lap bolt connections, motion coupling rigid body elements are established for the bolt holes, and the active point of the rigid body element is located at the center of the circular hole on the bolt shear surface; for symmetrical bolt connections, motion coupling rigid body elements are established for the middle bolt hole, and distributed coupling rigid body elements are established for the bolt holes on both sides, and the active point of the rigid body element is located at the center of the middle bolt hole. Then, spring connections are established between the active points of the rigid body elements, and the connection stiffness is related to the bolt size and material. Symmetrical bolt connections are three-hole connections, and lap bolt connections are two-hole connections.

[0004] In summary, for models that require a large number of bolt connections, it is necessary to establish a large number of rigid body elements, spring elements, and local coordinate systems to simulate the bolt connections. At the same time, it is necessary to manually calculate the connection stiffness of each bolt in each direction, which is a huge workload and has high labor costs. Summary of the invention

[0005] In order to solve the above problems, the present application provides an automatic modeling method for simulating bolt connections using ABAQUS spring elements, including:

[0006] Step S1: Import an external assembly model and obtain the hole surfaces of all parts of the assembly model by searching;

[0007] Step S2: Obtain the vertices corresponding to each hole surface, associate the hole surface with the vertex, and establish a search group with all vertices;

[0008] Step S3: taking a group of vertices in the searched group as search vertices, and removing the search vertices in the searched group to form a new searched group; translating the minimum envelope surface of the hole surface associated with the search vertices along the hole axis to form a new minimum envelope surface;

[0009] Step S4: searching for a vertex in the searched group through the new minimum envelope surface, and if the vertex exists, pairing the hole surface associated with the searched vertex with the hole surface associated with the found vertex to establish hole pair information;

[0010] Step S5: Create rigid body elements and spring elements based on the hole pair information.

[0011] Preferably, the method for searching the hole surface includes:

[0012] Find the curvature continuous surface of each part, determine the number of curvature continuous surfaces of each part, and determine it as a torus when the number of surfaces is 2 and the vertices of the two surfaces are the same; if the curvatures of the two curves on a torus are equal, the torus is a cylinder, otherwise the torus is a cone;

[0013] Get the minimum cube of the enveloping cylinder. When the minimum cube has no other faces, the cylinder is a hole face.

[0014] Preferably, the hole surface is formed by connecting two half hole surfaces, and the semicircular arc edge lines at both ends of the two half hole surfaces are connected to form the vertex, each hole surface correspondingly includes an upper vertex and a lower vertex, and the upper vertex is associated with the hole surface, and the lower vertex is associated with the hole surface, respectively, and the search group includes all lower vertices and upper vertices.

[0015] Preferably, in step S3, translating the minimum envelope surface of the hole surface associated with the search vertex along the hole axis specifically includes: when the vertex is an upper vertex, translating the minimum envelope surface upward along the hole axis; when the vertex is a lower vertex, translating the minimum envelope surface downward along the hole axis.

[0016] Preferably, when the hole surface in one hole pair information is the same as the hole surface in different hole pair information, the two hole pair information correspond to a symmetrical bolt connection, otherwise it is a lap bolt connection, the symmetrical bolt connection is a three-hole connection, and the lap bolt connection is a two-hole connection.

[0017] Preferably, each hole face is assigned a unique number for identifying whether different hole pair information has the same hole face.

[0018] Preferably, when the connection type is a lap bolt connection, motion coupling rigid body elements are established for the holes respectively, and the active point of the rigid body element is located at the center of the circular hole on the bolt shear surface.

[0019] Preferably, when the connection type is a symmetrical bolt connection, a motion coupling rigid body element is established for the middle bolt hole, and a distributed coupling rigid body element is established for the bolt holes on both sides, and the active point of the rigid body element is located at the center of the middle bolt hole.

[0020] Preferably, the bolt tensile and shear connection stiffness is calculated based on the hole diameter, height information, bolt material information, and part material information, a spring element is established, the rigid body element is connected with the spring element, and the spring stiffness is assigned.

[0021] Preferably, in the process of establishing the spring element, in order to ensure that the direction of the spring is consistent with the direction of the bolt, a local coordinate system is established according to the hole information. The distance of the minimum envelope surface translation in step S3 is the axial spacing of the bolt hole to the interface. The distance is the thickness of the gasket.

[0022] The advantages of this application include: the use of this method can greatly simplify the modeling work of engineers when establishing a finite element model that needs to simulate bolt connections, and can realize the automatic creation of spring elements to simulate bolt connections, reduce modeling time, avoid human errors, and improve work efficiency and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of an automatic modeling method for simulating bolt connections using ABAQUS spring elements in a preferred embodiment of the present application. Figure 2 This is a schematic diagram of the operating principle of a BoundingCylinder in a preferred embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be further described in detail in detail and in detail in conjunction with the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0025] As shown in the figure, in order to solve the above problems, the present application provides an ABAQUS spring element simulation bolt connection automatic modeling method, including:

[0026] The process flow is as follows:

[0027] (1) Import the external assembly model and assign material properties to each part;

[0028] (2) By finding the curvature-continuous surface of each part, determine the number of the curvature-continuous surfaces. If the number of surfaces is 2 and the vertices of the two surfaces are the same, it is determined to be a torus;

[0029] (3) Obtaining the radius and height information of the torus. If the curvatures of the two curves on a surface (torus) are equal, the surface (torus) is a cylinder; otherwise, the surface (torus) is a cone.

[0030] (4) Get the box area of ​​the torus and use it to reselect. If the face numbers of the selected faces are consistent, it is a hole face. At this point, the hole face information of all parts can be found. In other words, the first thing found is the cylinder, which may be a hole or a protruding cylinder. Search through the smallest cube that envelops the cylinder. If there is no new face in the box area, it is a hole face, otherwise it is a cylinder.

[0031] (5) Obtain the four vertex information on the hole surfaces of all parts, put the vertices at the upper and lower ends of the hole into different groups, associate the hole surface information with the hole vertex information, and assign a unique number to each hole surface;

[0032] (6) All vertices of the hole surfaces of all parts are set up as a search group;

[0033] (7) Start from the top vertex of the first hole of the first part and search for the bolt hole connected to it.

[0034] Take the vertex of the hole as a search group, remove the search group from the vertex of the search group, form a new search group, translate the minimum envelope surface of the hole surface, the minimum envelope surface is the minimum cylinder of the envelope cylinder, use BoundingCylinder, translate the BoundingCylinder along the hole axis to the search point direction by distance (this distance is the axial spacing of the bolt hole interface, generally the thickness of the gasket) to form a new BoundingCylinder, use the new BoundingCylinder to search for the hole point in the search group, if the hole point exists, then record the hole surface information and part information of the hole point, and establish the hole pair information by pairing the search point information and the found point information. Figure 2 As shown, BoundingCylinder is a cube slightly larger than the search hole. If a new vertex is found in the cube, the corresponding hole surface can be found through the new vertex, thereby determining the hole 1 that needs to be connected to the hole 2.

[0035] It should be noted that BoundingCylinder is a tool used for geometric calculations and spatial analysis, especially in computer graphics and engineering. It defines a cylinder that can be used to enclose all points or objects in an area. BoundingCylinder is mainly used to determine whether all points or objects in an area are located within a cylinder. Its basic parameters include the center point coordinates, radius, and height of the cylinder (determined by the center coordinates of the upper and lower end faces). Through these parameters, it is possible to determine whether a point or object is within the cylinder, which has important applications in 3D modeling, collision detection, path planning, etc.

[0036] (8) According to the hole pair information, find out whether the same hole face number appears in different hole pair information. If so, the hole connection is a symmetrical connection, otherwise it is an overlap connection;

[0037] (9) According to the connection type, a rigid body element is established. For a lap bolt connection, a motion coupling rigid body element is established for each bolt hole. The active point of the rigid body element is located at the center of the circular hole on the bolt shear surface. For a symmetrical bolt connection, a motion coupling rigid body element is established for the middle bolt hole. A distributed coupling rigid body element is established for the bolt holes on both sides. The active point of the rigid body element is located at the center of the middle bolt hole.

[0038] (10) Calculate the bolt tensile and shear connection stiffness based on the hole diameter, height information, bolt material information, and connected parts material information, connect the rigid body elements with spring elements, and assign spring stiffness;

[0039] (11) In the process of establishing the spring element, in order to ensure that the direction of the spring is consistent with the direction of the bolt, it is necessary to establish a local coordinate system based on the hole information;

[0040] (12) Use RSG Dialog Builder in ABAQUS to create a GUI interface. Figure 1 shown.

[0041] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An automatic modeling method for simulating bolt connections using ABAQUS spring elements, characterized in that: include: Step S1: Import an external assembly model and obtain the hole surfaces of all parts of the assembly model by searching; Step S2: Obtain the vertices corresponding to each hole surface, associate the hole surface with the vertex, and establish a search group with all vertices; Step S3: taking a group of vertices in the searched group as search vertices, and removing the search vertices in the searched group to form a new searched group; The minimum envelope surface of the hole surface associated with the search vertex is translated along the hole axis to form a new minimum envelope surface; Step S4: searching for a vertex in the searched group through the new minimum envelope surface, and if the vertex exists, pairing the hole surface associated with the searched vertex with the hole surface associated with the found vertex to establish hole pair information; Step S5: Create rigid body elements and spring elements based on the hole pair information.

2. The ABAQUS spring element simulation bolt connection automatic modeling method according to claim 1 is characterized in that: The methods for finding hole faces include: Find the curvature continuous surface of each part, determine the number of curvature continuous surfaces of each part, and determine it as a torus when the number of surfaces is 2 and the vertices of the two surfaces are the same; if the curvatures of the two curves on a torus are equal, the torus is a cylinder, otherwise the torus is a cone; Get the minimum cube of the enveloping cylinder. When the minimum cube has no other faces, the cylinder is a hole face.

3. The ABAQUS spring element simulation bolt connection automatic modeling method according to claim 1 is characterized in that: The hole surface is formed by connecting two half hole surfaces, and the semicircular arc edge lines at both ends of the two half hole surfaces are connected to form the vertex. Each hole surface corresponds to an upper vertex and a lower vertex. The upper vertex is associated with the hole surface, and the lower vertex is associated with the hole surface respectively. The search group includes all lower vertices and upper vertices.

4. The ABAQUS spring element simulation bolt connection automatic modeling method as claimed in claim 3 is characterized in that: In step S3, the minimum envelope surface of the hole surface associated with the search vertex is translated along the hole axis, specifically including: when the vertex is an upper vertex, the minimum envelope surface is translated upward along the hole axis; when the vertex is a lower vertex, the minimum envelope surface is translated downward along the hole axis.

5. The ABAQUS spring element simulation bolt connection automatic modeling method as claimed in claim 4 is characterized in that: When the hole surface in one hole pair information is the same as the hole surface in different hole pair information, the two hole pair information correspond to a symmetrical bolt connection, otherwise it is a lap bolt connection, the symmetrical bolt connection is a three-hole connection, and the lap bolt connection is a two-hole connection.

6. The ABAQUS spring element simulation bolt connection automatic modeling method according to claim 5, characterized in that: Each hole face is assigned a unique number, which is used to identify whether different hole pair information has the same hole face.

7. The ABAQUS spring element simulation bolt connection automatic modeling method according to claim 5, characterized in that: When the connection type is lap bolt connection, a motion-coupled rigid element is established for the hole, and the active point of the rigid element is located at the center of the circular hole on the bolt shear surface.

8. The ABAQUS spring element automatic modeling method for simulating bolt connection according to claim 7, characterized in that: When the connection type is symmetrical bolt connection, a motion coupling rigid body element is established for the middle bolt hole, and a distributed coupling rigid body element is established for the bolt holes on both sides. The active point of the rigid body element is located at the center of the middle bolt hole.

9. The ABAQUS spring element simulation bolt connection automatic modeling method according to claim 8, characterized in that: According to the hole diameter, height information, bolt material information, and part material information, the bolt tensile and shear connection stiffness is calculated, the spring element is established, the rigid body element is connected with the spring element, and the spring stiffness is assigned.

10. The ABAQUS spring element simulation bolt connection automatic modeling method according to claim 8, characterized in that: In the process of establishing the spring element, in order to ensure that the direction of the spring is consistent with the direction of the bolt, a local coordinate system is established based on the hole information.

11. The ABAQUS spring element simulation bolt connection automatic modeling method according to claim 8, characterized in that: The distance of the minimum envelope surface translation in step S3 is the axial spacing between the bolt holes and the interface.

12. The ABAQUS spring element automatic modeling method for simulating bolt connection according to claim 11, characterized in that: The distance is the thickness of the gasket.

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