ABAQUS spring element simulation bolt connection automatic modeling method

Abstract

The application belongs to the technical field of electric data processing, and particularly relates to an automatic modeling method for simulating bolt connection by ABAQUS spring element, steps S1: importing an external assembly model, and obtaining hole surfaces of all parts of the assembly model by searching; step S2: obtaining corresponding vertices of each hole surface, and establishing association between the hole surface and the vertex, and establishing a searched group with all the vertices; step S3: taking a group of vertices in the searched group as searched vertices, and removing the searched vertices in the searched group to form a new searched group; translating a BoundingCylinder of a hole surface associated with the searched vertices along a hole axial direction to form a new BoundingCylinder; step S4: searching the vertices in the searched group through the new BoundingCylinder, and when the vertices exist, establishing hole pair information in pairs with the hole surface associated with the searched vertices and the hole surface associated with the searched vertices; and step S5: creating a rigid element and a spring element based on the hole pair information.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electric data processing, and particularly relates to an automatic modeling method for simulating bolt connection by ABAQUS spring element. BACKGROUND

[0002] The joints are usually connected by bolt groups, and the bolts are generally subjected to tension, shear or combined tension and shear. When analyzing the strength of joint parts, in order to simulate the accurate working condition of the joint, finite element simulation of multiple bolt connections is required. At least two stiffnesses along the shear direction and one stiffness along the tension direction of the bolt should be defined, and a local coordinate system should be defined if necessary to ensure that the force direction of the spring element is the same as the real force direction of the bolt.

[0003] The bolt connection is divided into two types, i.e. lap bolt connection and symmetric bolt connection. For the lap bolt connection, a motion-coupled rigid element is established for each bolt hole, and the driving point of the rigid element is located at the center of the bolt shear plane hole. For the symmetric bolt connection, a motion-coupled rigid element is established for the middle bolt hole, and a distributed-coupled rigid element is established for the two side bolt holes, and the driving point of the rigid element is located at the center of the middle bolt hole. Then, a spring connection is established between the driving points of the rigid elements, and the connection stiffness is related to the size and material of the bolt. The symmetric bolt connection is a three-hole connection, and the lap bolt connection is a two-hole connection.

[0004] As described above, for a model requiring more bolt connections, a large number of rigid elements, spring elements and local coordinate systems need to be established to simulate the bolt connection, and the connection stiffness of each bolt in each direction needs to be manually calculated, which is a huge workload and has a high labor cost. SUMMARY

[0005] In order to solve the above problems, the application provides an automatic modeling method for simulating bolt connection by ABAQUS spring element, which comprises the following steps:

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

[0007] Step S2: obtaining corresponding vertices of each hole surface, and associating the hole surface with the vertices, and establishing a searched group with all the vertices;

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

[0009] Step S4: searching for vertices in the searched group through the new minimum envelope surface, and when the vertices exist, establishing hole pair information in pairs for the hole surface associated with the searched vertices and the hole surface associated with the searched vertices.

[0010] Step S5: creating rigid body element and spring element based on hole pair information.

[0011] Preferably, the hole surface searching method comprises:

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

[0013] Obtain the minimum cube of the envelope cylinder, when the minimum cube has no other surface, the cylinder is a hole surface.

[0014] Preferably, the hole surface is formed by butting two half hole surfaces, the semicircular arc edge lines at both ends of the two half hole surfaces are butted to form the vertex, each hole surface corresponds to an upper vertex and a lower vertex, the upper vertex and the hole surface are associated, the lower vertex and the hole surface are associated, and the searched group includes all lower vertices and upper vertices.

[0015] Preferably, in step S3, the minimum envelope surface of the searched vertex associated hole surface is translated along the hole axis, specifically comprising: when the vertex is an upper vertex, the minimum envelope surface is translated upward along the hole axis, and when the vertex is a lower vertex, the minimum envelope surface is translated 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 corresponds 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 surface is assigned a unique number for identifying whether the same hole surface exists in different hole pair information.

[0018] Preferably, when the connection type is a lap bolt connection, a motion-coupled rigid body element is established for each hole, and the driving point of the rigid body element is located at the center of the bolt shear surface circular hole.

[0019] Preferably, when the connection type is a symmetrical bolt connection, a motion-coupled rigid body element is established for the middle bolt hole, and distributed-coupled rigid body elements are established for the two side bolt holes, and the driving point of the rigid body element is located at the center of the middle bolt hole.

[0020] Preferably, according to the hole diameter, height information and bolt material information, part material information, the bolt tensile and shear connection stiffness is calculated, a spring element is established, the rigid body element is connected by 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 spring direction is consistent with the bolt direction, 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 pair interface. The distance is the gasket thickness.

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

[0023] Figure 1 is a preferred embodiment of the present application ABAQUS spring element simulation of bolt connection automatic modeling method flow chart.

[0024] Figure 2 is a preferred embodiment of the present application BoundingCylinder operating principle diagram. DETAILED DESCRIPTION

[0025] In order to make the technical scheme of the present application and its advantages clearer, the technical scheme of the present application will be described in further detail below with reference to the drawings. It should be understood that the specific embodiments described herein are only part of the embodiments of the present application, and are only used to explain the present application, but not to limit the present application. It should be noted that, in order to facilitate description, only parts related to the present application are shown in the drawings, and other related parts can be referred to the usual design. In the case of no conflict, the embodiments in the present application and the technical features in the embodiments can be combined to obtain new embodiments.

[0026] In order to solve the above problems, the present application provides an ABAQUS spring element simulation of bolt connection automatic modeling method, comprising:

[0027] The program flow is as follows:

[0028] (1) Import the external assembly model, and give each part material properties;

[0029] (2) By finding the curvature continuous surface of each part, judging the number of curvature continuous surfaces, if the number of surfaces is 2, and the vertexes of the two surfaces are the same, then it is determined as a torus;

[0030] (3) Get the torus radius height information, if the curvatures of two curves on a surface (torus) are equal, then the surface (torus) is a cylinder, otherwise the surface (torus) is a conical surface;

[0031] (4) Get the box region of the torus surface and reselect it with the box region. If the face number of the selected surface is consistent before and after, it is a hole surface. At this point, all the hole surface information of the part can be found. That is, the cylindrical surface is actually found first. This cylindrical surface may be a hole or a protruding cylinder. Find it by the smallest cube of the envelope cylindrical surface. If there is no new surface in the box region, it is a hole surface, otherwise it is a cylindrical body.

[0032] (5) Get the four vertex information on all part hole surfaces, put the top and bottom vertices of the hole into different groups respectively, and associate the hole surface information with the hole vertex information. Assign a unique number to each hole surface;

[0033] (6) Establish a searched group for all vertices of all hole surfaces of all parts;

[0034] (7) Start searching from the top vertex of the first hole of the first part,

[0035] The hole vertex is taken as a search group, the search group is removed from the searched group vertex to form a new searched group, and the smallest envelope surface of the hole surface is translated. The smallest envelope surface is the smallest cylinder of the envelope cylindrical surface. BoundingCylinder is used to translate the BoundingCylinder along the hole axis direction to find the point direction distance (the distance is the axial distance of the bolt hole pair interface, which is generally the thickness of the gasket) to form a new BoundingCylinder. Find the hole point in the searched group through the new BoundingCylinder. If the hole point exists, record the hole surface information and part information of the hole point. Pair the search point information and the found point information to establish hole pair information. As shown in Figure 2 BoundingCylinder is a slightly larger cube than the search hole. If a new vertex is found in the cube, the corresponding hole surface can be found through the new vertex to determine the hole 1 that needs to establish a connection relationship with the hole 2.

[0036] It should be noted that BoundingCylinder (BoundingCylinder) is a tool for geometric calculation and spatial analysis, widely used in computer graphics and engineering fields. It defines a cylinder that can be used to enclose all points or objects within a region. BoundingCylinder is mainly used to determine whether all points or objects within a region are located within a cylinder. Its basic parameters include the center point coordinates of the cylinder, the radius and the height (determined by the center coordinates of the upper and lower end surfaces). Through these parameters, it can be judged whether a point or object is within the cylinder, which has important applications in three-dimensional modeling, collision detection, path planning, etc.

[0037] (8) According to the hole pair information, it is checked whether the same hole surface number appears in different hole pair information, if it appears, the hole is connected as symmetric connection, otherwise it is connected as lap joint;

[0038] (9) According to the connection type, the rigid body element is established, for lap joint bolt connection, the motion coupling rigid body element is established for the bolt hole, the driving point of the rigid body element is located at the center of the bolt shear plane circular hole, for symmetric bolt connection, the motion coupling rigid body element is established for the middle bolt hole, the distributed coupling rigid body element is established for the two side bolt holes, the driving point of the rigid body element is located at the center of the middle bolt hole;

[0039] (10) According to the hole diameter, height information and bolt material information, the connected part material information is calculated, the bolt tensile and shear connection stiffness is calculated, the spring element is connected with the rigid body element, and the spring stiffness is given;

[0040] (11) In the process of establishing the spring element, in order to ensure that the spring direction is consistent with the bolt direction, the local coordinate system needs to be established according to the hole information;

[0041] (12) The RSG Dialog Builder in ABAQUS is used to establish the GUI interface, the interface is shown as Figure 1 .

[0042] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An ABAQUS spring element simulation bolt connection automatic modeling method, characterized in that, The method comprises the following steps: Step S1: importing an external assembly model, and obtaining hole surfaces of all parts of the assembly model by searching; Step S2: obtaining a vertex corresponding to each hole surface, and establishing an association between the hole surface and the vertex, and establishing a searched group with all the vertices; Step S3: taking a group of vertices in the searched group as searched vertices, and removing the searched vertices in the searched group to form a new searched group; Translating a minimum envelope surface of the hole surface associated with the searched vertices along an axial direction of the hole to form a new minimum envelope surface; Step S4: searching for a vertex in the searched group through the new minimum envelope surface, and when the vertex exists, establishing hole pair information in pairs between the hole surface associated with the searched vertex and the hole surface associated with the searched vertex; Step S5: creating a rigid body element and a spring element based on the hole pair information; 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 symmetric bolt connection, otherwise, the two hole pair information correspond to a lap bolt connection, the symmetric bolt connection is a three-hole connection, and the lap bolt connection is a two-hole connection; When the connection type is the lap bolt connection, a motion-coupled rigid body element is established for each hole, and a driving point of the rigid body element is located at a center of a bolt shear surface circular hole; When the connection type is the symmetric bolt connection, a motion-coupled rigid body element is established for a middle bolt hole, and distributed-coupled rigid body elements are established for two side bolt holes, and a driving point of the rigid body element is located at a center of the middle bolt hole; According to hole diameter, height information and bolt material information, part material information, bolt tensile and shear connection stiffness are calculated, a spring element is established, the rigid body element is connected with the spring element, and spring stiffness is given.

2. The ABAQUS spring element analogy bolt connection automatic modeling method of claim 1, wherein, The searching method of the hole surface comprises the following steps: Searching for a curved surface with continuous curvature of each part, judging a number of the curved surfaces with continuous curvature of each part, determining a torus when the number of the curved surfaces is 2 and the vertices of the two curved surfaces are the same, determining a cylinder when curvatures of two curves on a torus are equal, and determining a conical surface when the curvatures of the two curves on the torus are not equal, and obtaining a minimum cube of an envelope cylinder, and determining the cylinder as a hole surface when the minimum cube has no other surface.

3. The ABAQUS spring element analogy bolt connection automatic modeling method of claim 1, wherein, The hole surface is formed by butting two half hole surfaces, and a semicircular arc edge line at two ends of the two half hole surfaces is butted to form the vertex, each hole surface corresponds to the upper vertex and the lower vertex, an association between the upper vertex and the hole surface is established, an association between the lower vertex and the hole surface is established, and the searched group comprises all the lower vertices and the upper vertices.

4. The ABAQUS spring element analogy bolt connection automatic modeling method of claim 3, wherein, In step S3, the minimum envelope surface of the hole surface associated with the searched vertices is translated along the axial direction of the hole, and the minimum envelope surface is translated upward along the axial direction of the hole when the vertex is the upper vertex, and the minimum envelope surface is translated downward along the axial direction of the hole when the vertex is the lower vertex.

5. The ABAQUS spring element analogy bolt connection automatic modeling method of claim 1, wherein, Each hole surface is given a unique number for identifying whether the hole surface is the same in different hole pair information.

6. The ABAQUS spring element analogy bolt connection automatic modeling method of claim 1, wherein, In the process of establishing the spring element, a local coordinate system is established according to the hole information to ensure that the spring direction is consistent with the bolt direction.

7. The ABAQUS spring element analogy bolt connection automatic modeling method of claim 1, wherein, The distance of the translation of the minimum envelope surface in step S3 is an axial distance of an interface of the bolt hole pair.

8. The ABAQUS spring element analogy bolt connection automatic modeling method of claim 7, wherein, The distance is the thickness of the gasket.

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