Strength analysis method for lower control arm of heavy truck

Abstract

The invention relates to a strength analysis method for a lower control arm of a heavy truck, and solves the problems that the design iteration period is prolonged and the cost is increased due to the fact that a deviation exists between a traditional analysis method and a real working condition and the strength needs to be verified through a large number of bench tests in the later period. Selecting a lower control arm front end point, a lower control arm rear end point, a spiral spring lower end point and a spherical hinge point from the initial finite element model as nodes for extracting loads, endowing material parameters of the lower control arm: an elastic model, density and Poisson's ratio, and laying a foundation for building a multi-body dynamic model; when the multi-body dynamic model is built, template models of tires, suspensions and flexible bodies are built, a whole vehicle assembly model is assembled, loading of a vertical bending working condition, a horizontal bending working condition and a torsion working condition is carried out, loads of all nodes are submitted, calculated and extracted, the loads are reversely loaded to a complete finite element model, and a strength analysis result of the lower control arm is obtained through calculation. A simulation analysis result is closer to a real vehicle reliability test result.

Description

TECHNICAL FIELD

[0001] The present application relates to a heavy truck lower control arm strength analysis method, belonging to the field of automobile suspension. BACKGROUND

[0002] The traditional strength simulation analysis of the lower control arm of the heavy truck independent suspension is to calculate the stress distribution under load by the finite element method to determine whether it meets the strength requirements.

[0003] The traditional analysis method of the lower control arm at present is mainly based on the assumption of linear elasticity, ignoring the material nonlinearity, contact friction and other complex factors, only simulating the lower control arm alone, and the boundary conditions and working condition loading are also constrained and loaded according to the experience value, which is suitable for rapid strength evaluation in the early stage of design. But this analysis method has some defects, mainly due to the distortion of the simplification of contact and friction, low simulation accuracy, not installing the lower control arm on the whole vehicle for whole vehicle working condition analysis and calculation, and the boundary conditions and working condition loading have limitations in simulating the real working condition, which deviates from the real working condition, and a large number of bench tests are needed to verify the strength in the later stage, which prolongs the design iteration cycle and increases the cost. SUMMARY

[0004] The present application provides a heavy truck lower control arm strength analysis method, which solves the problem of deviation between the traditional analysis method and the real working condition, the need for a large number of bench tests to verify the strength in the later stage, the prolongation of the design iteration cycle and the increase of the cost.

[0005] The present application is realized by the following technical solutions:

[0006] A heavy truck lower control arm strength analysis method, comprising the following steps:

[0007] Step 1: Finite element model establishment:

[0008] 1) Geometric topology repair of the whole vehicle three-dimensional model and the lower control arm, eliminating small features, redundant geometric elements, complex transition structures, non-analysis target area details, simplifying the complex model, improving the speed and quality of mesh division, and reducing the calculation error;

[0009] 2) Unit mesh division, selecting Tetras unit mesh type according to the model characteristics of the lower control arm, confirming the mesh size of the lower control arm as 5mm according to the computer capacity and the required accuracy, and obtaining the initial finite element model;

[0010] 3) In the initial finite element model, the lower control arm front end point, the lower control arm rear end point, the lower end point of the coil spring and the ball hinge point are selected as the nodes for extracting the load, and the material parameters of the lower control arm are assigned: elastic model, density, Poisson's ratio, one is to obtain a complete finite element model, and the load is loaded on the model after the load extraction, and the analysis result is obtained, and two is to simplify the model contour line, set the header card information, establish the Interface Part to obtain the flexible body file, and lay the foundation for building a multi-body dynamics model;

[0011] Step 2: Multi-body dynamics model building:

[0012] 1) Create a template model of the tire, the suspension and the flexible body;

[0013] 2) Generate a subsystem model according to the template model, and then assemble each subsystem into a whole vehicle assembly model;

[0014] 3) Perform vertical bending, horizontal bending and torsion loading, and submit calculation to extract the load of each node;

[0015] Step 3: Load the load of each node extracted by the multi-body dynamics on the complete finite element model, and the strength analysis result of the lower control arm can be obtained by calculation.

[0016] The present application combines finite element analysis and multi-body dynamics, performs multidisciplinary joint simulation, extracts the load of the selected nodes of the lower control arm in the whole vehicle model, and analyzes the strength of the lower control arm structure by using the inertia release method. The connection relationship between the parts is closer to the real situation, the simulation precision is higher, the boundary conditions and the working condition loading are closer to the real working condition, and the simulation analysis result is closer to the real vehicle reliability test result. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a basic flowchart of the present application. DETAILED DESCRIPTION

[0018] The present application provides an analysis method for calculating the strength of the lower control arm of a heavy truck. The method mainly includes two parts: the establishment of a finite element model and the building of a multi-body dynamics model, Figure 1 is a basic flowchart of the present application.

[0019] When the finite element model is established, firstly, the three-dimensional numerical model of the whole vehicle and the lower control arm are geometrically topologically repaired, the micro features, redundant geometric elements, complex transition structures and non-analysis target area details are eliminated, the complex model is simplified, the speed and quality of mesh division are improved, and the calculation error is reduced; secondly, unit mesh division is carried out, the Tetras unit mesh type is selected according to the model characteristics of the lower control arm, the mesh size of the lower control arm is confirmed to be 5mm according to the computer capacity and the required accuracy, and the initial finite element model is obtained; then the front end point of the lower control arm, the rear end point of the lower control arm, the lower end point of the coil spring and the spherical hinge point are selected as the nodes for extracting the load in the initial finite element model, and the material parameters of the lower control arm, such as elastic model, density, Poisson's ratio, etc., are given, one is to obtain a complete finite element model, after the load extraction is completed, the load is loaded on the model, and the analysis result is obtained, and two is to simplify the model contour line, set the header file card information, establish the Interface Part and obtain the flexible body file, so as to lay the foundation for building the multi-body dynamics model.

[0020] When the multi-body dynamics model is built, firstly, the template model (Template) of the tire, the suspension and the flexible body is created, secondly, the subsystem model (Subsystem) is generated according to the template model, then each subsystem is assembled into the whole vehicle assembly model (Assembly), and then the vertical bending condition, the horizontal bending condition and the torsion condition are loaded, finally, the calculation is submitted, and the load of each node can be extracted.

[0021] Finally, the load of each node extracted by the multi-body dynamics is loaded reversely on the complete finite element model, and the strength analysis result of the lower control arm can be obtained by calculation.

[0022] The present application improves the accuracy of the strength simulation analysis of the lower control arm, controls the design risk in the digital space to a greater extent, reduces the verification times of the lower control arm by the bench test and the reliability test, shortens the design iteration cycle, reduces the research and development cost, and improves the product performance.

Claims

1. A method of strength analysis of a heavy truck lower control arm, characterized by: Comprising the following steps: Step 1: Finite element model establishment: 1) The three-dimensional model of the whole vehicle and the lower control arm are topologically repaired to eliminate small features, redundant geometric elements, complex transition structures, and non-analysis target area details, simplify the complex model, improve the speed and quality of meshing, and reduce calculation errors; 2) Element meshing is performed, the Tetras element mesh type is selected according to the characteristics of the lower control arm model, the mesh size of the lower control arm is confirmed according to the computer capacity and the required accuracy, and the initial finite element model is obtained; 3) The front end point of the lower control arm, the rear end point of the lower control arm, the lower end point of the coil spring, and the spherical hinge point are selected as the nodes for extracting the load in the initial finite element model, and the material parameters of the lower control arm are assigned: elastic model, density, Poisson's ratio, one is to obtain a complete finite element model, and the load is loaded on the model after the load extraction, to obtain the analysis result, and two is to simplify the model contour line, set the header card information, and establish the Interface Part to obtain the flexible body file, to lay the foundation for building a multi-body dynamics model; Step 2: Multi-body dynamics model building: 1) Create template models of tires, suspensions, and flexible bodies; 2) Generate subsystem models according to the template models, and then assemble each subsystem into a whole vehicle assembly model; 3) Perform vertical bending, horizontal bending, and torsion loading, and submit the calculation to extract the load of each node; Step 3: Load the load of each node extracted by the multi-body dynamics on the complete finite element model, and the strength analysis result of the lower control arm can be obtained by calculation.

2. The method of strength analysis of a lower control arm of a heavy duty truck as claimed in claim 1, wherein: In step 1, the mesh size of the lower control arm is divided into 5mm when establishing the finite element model.

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