Finite Element And Test Analysis On The Body Frame Structure Of A Mini-EV

With the development of Computer and Technology, FEM(finite element method) has showed its advantage in the field of automotive, which is different from traditional design method, this method is applied to achieve the design and analysis of parallel during automotive conceptual design phase, not only to shorten the design cycle, but also reduce the development costs, and is a very efficient method of engineering analysis. It has been proved that FEM in vehicle body frame analysis is very efficient and necessary. By analyzing the body structure of the static and dynamic and evaluating Analysis results, it can precede strength, stiffness, natural frequency, vibration model and the vehicle body of stress distributions and deformation situation, all of these are the foundation for the future work.In this paper, a type A00 mini electric vehicle which is independent research and development by a company is taken as an example, firstly a geometry model of the body frame was established by using the software UG, and the finite element model was set up by the software HYPERMESH. In the finite element model-building process should consider the main issues, including simplifying geometric model, the unit system and the performance of materials, unit selection and mesh, the scale model of control, the quality of the model of inspection, load handling, spot handing. In the finite element model should use the shell element structure, the calculation of the final model contains 65328 nodes, 68311 units; the number of triangle units is 282, and the ratio of triangle unit is 0.4%.Based on the actual situation of mini car body, using finite element software NASTRAN analyzes this body frame of the characteristics of stiffness and strength in the conditions of static bending and bending and torsion combination, through the analysis of the body frame of strength and stiffness, it can precede the body frame of stress distributions and deformation situation, and reach its weaknesses to improve and optimize the structure of the reference.The modal parameters of mini car body frame structure is an important vehicle performance parameters, as designing vehicle body frame, model frequency should stagger vibration frequency to avoid resonance. According to dynamic performance requirements of the pure electric car has a modal analysis of the body frame, 14 free vibrating modes are calculated, and reach the natural frequency of vibration mode and the weak link of body frame. Comparing test mode result with simulation mode analysis data, the finite element model is verified. Explaining the finite element model can more accurately simulate the natural mode of body frame. According to the finite element theory and actual situation of mini electric car body, this paper proposes a program to be in line with actual production and satisfy vehicle performance, at the same time, modal test method provides a reference with the same size as the future structure of the test mode. Through analyzing the finite element of the body frame structure, not only shorten the design and testing cycle, but also save a lot of test and production costs.