Processing method for automatically defining vehicle body riveting connection based on HyperMesh

Abstract

The invention discloses a processing method for automatically defining vehicle body riveting connection based on HyperMesh. The processing method comprises the following steps that (1) an aluminum profile and a connecting sheet middle face are established; (2) dividing grids of the aluminum profiles and the connecting pieces; (3) giving grid thickness information; (4) establishing a rivet hole center point; (5) establishing a rivet hole axis; (6) establishing rigid units connected by rivets; and (7) deleting the over-constrained rigid units. According to the method, the modeling time for defining the rivet connection of the vehicle body is shortened, and the processing time of three days is shortened to the processing time within one day; the work intensity of repeated work is reduced, and the labor intensity of engineers is relieved; the error probability of artificial modeling of engineers is reduced; standards for defining riveting connection in a finite element model are standardized.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle finite element simulation, and relates to a pre-processing method for quickly and automatically establishing a riveted connection of a vehicle body, and specifically to a processing method for automatically defining a riveted connection of a vehicle body based on HyperMesh. Background Art

[0002] Vehicle finite element analysis is a technology that uses mathematical approximation methods to analyze the mechanical properties of vehicle structures. The analysis process mainly includes pre-processing, solving, and post-processing. In the finite element analysis process of existing vehicles, the pre-processing stage accounts for a large proportion of the time, especially in the rigidity finite element analysis process, the proportion of pre-processing time sometimes even reaches 60% to 80% of the entire analysis process. Therefore, how to improve the efficiency of the pre-processing stage is an urgent problem to be solved.

[0003] During the finite element analysis of a vehicle, pre-processing includes steps such as meshing, defining materials, defining properties, and defining connections. At present, the pre-processing software HyperMesh has helped simulation engineers greatly improve their work efficiency in steps such as meshing, defining materials, and defining properties. However, due to the large number of types of connections between components in vehicle finite element simulation, and the different methods of defining connections in finite elements for each company, in the existing technology, when engineers use the rigid unit (RBE2 unit) in the Optistruct solver to simulate the riveted connection between parts, there is no existing riveted connection definition function to help engineers automatically and quickly establish 3,000 to 4,000 rivet connections on the body, which makes the entire pre-processing time longer, which not only increases the labor intensity of engineers but also increases the probability of modeling errors. Summary of the invention

[0004] The main purpose of the present invention is to provide a processing method for automatically defining riveted connections of a vehicle body based on HyperMesh, which can automatically establish 3000 to 4000 RBE2 units of the vehicle body in HyperMesh to replace the riveted connections, and check whether the degrees of freedom of these rigid units meet the calculation requirements, and remove over-constrained RBE2 units.

[0005] The technical solution of the present invention: A method for automatically defining a riveted connection of a vehicle body based on HyperMesh comprises the following steps: (1) Establish the mid-surface between the aluminum profile and the connecting piece; (2) Divide the aluminum profile and connecting piece grid; (3) Assigning grid thickness information; (4) Establish the center point of the rivet hole; (5) Establish the rivet hole axis; (6) Establishing a rigid unit connected by rivets; (7) Delete over-constrained rigid elements.

[0006] Preferably, the specific steps of step (1) to step (3) include: a) checking the number of entities in the component; b) selecting all entities; c) automatically extracting the mid-surface of each entity; d) automatically dividing each mid-surface; e) automatically assigning mesh thickness information; f) automatically adding the thickness information of the part to the suffix of the component.

[0007] Preferably, the specific steps of step (4) include: a) displaying the mid-surface model of the connecting piece separately; b) selecting all models; c) automatically establishing the center point of the circular hole of the mid-surface model.

[0008] Preferably, the specific steps of step (5) include: a) selecting the center point of the circular hole created in step (4); b) establishing the axis of the rivet hole.

[0009] Preferably, the specific steps of step (6) include: a) separately displaying the axis of the rivet hole created in step (5); b) displaying the grid model; c) setting the radius size of the rivet; d) Set the extension line size of the rivet axis; e) Automatically capture the nodes around the rivet hole and establish the RBE2 unit.

[0010] Preferably, the specific steps of step (7) include: a) checking the degrees of freedom of the 0D unit; b) displaying the over-constrained rigid units separately; c) selecting all the over-constrained rigid units; d) running the program to automatically delete the over-constrained rigid units.

[0011] The beneficial effects of the present invention are as follows: the present invention shortens the modeling time for defining the rivet connection of the vehicle body, shortening the processing time from three days to one day; reduces the workload of repetitive work and alleviates the labor intensity of engineers; reduces the probability of errors in manual modeling by engineers; and standardizes the standards for defining riveted connections in finite element models. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a flow chart of the design steps of an embodiment of the present invention; Figure 2 is a schematic diagram of a finite element model in an embodiment of the present invention; Figure 3 It is the program interface in the embodiment of the present invention; Figure 4 This is an interface for defining rivet connection in an embodiment of the present invention.

[0013] Wherein: 1. aluminum profile, 2. connecting piece, 3. rivet hole axis, 4. rivet connected rigid unit. DETAILED DESCRIPTION

[0014] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0015] Example like Figure 1 , Figure 2 The embodiment shown is a method for automatically defining the riveting connection of a vehicle body based on HyperMesh, and takes the side panels and top cover of a certain model of an all-aluminum vehicle body as processing objects, which includes the following steps: (1) Create the mid-surface between aluminum profile 1 and connecting piece 2 a) Click the Solid Thickness (1 / 2) button; b) Select the method of extracting the mid-surface as Offset; c) Set the object saved in the middle surface to the new Compoent; d) Select all entities; e) Run the mid-surface extraction program.

[0016] (2) Divide the mesh of aluminum profile 1 and connecting piece 2 a) Click the Solid Thickness (1 / 2) button; b) Set the grid size; c) Set the grid division criteria; d) Select the mid-surface model; e) Run the meshing program.

[0017] (3) Assign shell unit thickness information a) Click the Solid Thickness (1 / 2) button; b) Select the grid in the component; c) Select the entity in the component; d) Set the minimum and maximum thickness values; e) Calculate the unit thickness; f) Write the thickness value into the name suffix of the component; g) Click the Solid Thickness (2 / 2) button; h) View the generated ASSEMBLY model.

[0018] (4) Establish the center point of the rivet hole a) Click the Quantity Nodes button. b) Select all the lines of the mid-surface model; c) Run the program to establish the center point of the circular hole in the mid-surface model.

[0019] (5) Establish the rivet hole axis a) Click the Create Line command in Hypermesh; b) Select the center point of the circular hole created in step (4); c) Select the axial direction of the rivet hole; d) Establish the rivet hole axis 3.

[0020] (6) Establishing a rigid unit for rivet connection a) Click the BOLT X button, BOLT Y button or BOLT Z button according to the direction of the rivet hole axis; b) Select the rivet hole axis 3 created in step (5); c) Set the radius size of the rivet hole; d) Set the extension line size of the rivet hole axis; e) Run the program to establish the rivet connection rigid unit 4; (7) Delete over-constrained rigid elements a) Check the degrees of freedom of the 0D element; b) Display the over-constrained rigid elements separately; c) Depending on the type of rigid element, click the Dependency Rigid button or the Dependency RigidLink button; c) Select over-constrained rigid elements; d) Run the program and delete the over-constrained rigid elements.

[0021] This embodiment uses HyperMesh to automatically define the processing method for riveted connections of the vehicle body, and completes the meshing, thickness definition, and rivet connection of the aluminum vehicle body side and top cover in one day. The entire processing process greatly reduces repetitive work, and engineers only need to check or slightly modify the content processed by the program, which reduces the labor intensity of engineers and the probability of errors in manual modeling by engineers. HyperMesh's recognition ability in processing over-constrained units is increased, that is, all over-constrained units will not be deleted, but one unit in the over-constrained unit set will be retained, which standardizes the standard for defining riveted connections in finite element models.

[0022] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements may be made without departing from the inventive concept of the present invention, which all fall within the protection scope of the present invention.

Claims

1. A method for automatically defining riveted connections of a vehicle body based on HyperMesh, characterized in that: The following steps are involved: (1) Establish the mid-surface between the aluminum profile and the connecting piece; (2) Divide the aluminum profile and connecting piece grid; (3) Assigning grid thickness information; (4) Establish the center point of the rivet hole; (5) Establish the rivet hole axis; (6) Establish a rigid unit connected by rivets; (7) Delete over-constrained rigid elements.

2. A method for automatically defining riveted connections of a vehicle body based on HyperMesh as claimed in claim 1, characterized in that: The specific steps of step (1) to step (3) include: a) checking the number of entities in the component; b) selecting all entities; c) automatically extracting the mid-surface of each entity; d) automatically dividing each mid-surface; e) automatically assigning mesh thickness information; f) automatically adding the thickness information of the part to the suffix of the component.

3. The method for automatically defining riveted connections of a vehicle body based on HyperMesh as claimed in claim 1, characterized in that: The specific steps of step (4) include: a) displaying the mid-surface model of the connecting piece separately; b) selecting all models; and c) automatically establishing the center point of the circular hole of the mid-surface model.

4. The method for automatically defining riveted connections of a vehicle body based on HyperMesh as claimed in claim 1, characterized in that: The specific steps of step (5) include: a) selecting the center point of the circular hole created in step (4); b) establishing the axis of the rivet hole.

5. The method for automatically defining riveted connections of a vehicle body based on HyperMesh as claimed in claim 1, characterized in that: The specific steps of step (6) include: a) separately displaying the axis of the rivet hole created in step (5); b) displaying the mesh model; c) setting the radius size of the rivet; d) setting the extension line size of the rivet axis; e) automatically grabbing the nodes around the rivet hole and establishing the RBE2 unit.

6. The method for automatically defining riveted connections of a vehicle body based on HyperMesh as claimed in claim 1, characterized in that: The specific steps of step (7) include: a) checking the degrees of freedom of the 0D unit; b) displaying the over-constrained rigid units separately; c) selecting all the over-constrained rigid units; d) running the program to automatically delete the over-constrained rigid units.

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