Study On Structure Analysis And Design Technologies Of Car Body

Accurately forecasting the characteristics of vehicles during the process of 3D digital design is a hot point of the research technologies on vehicles in nowadays. The FEM (finite element method) offers an advanced method for the analysis and design of vehicles. During the initial stages of design the FEM analysis of vehicles could help engineers find the problem that exist in the design. Nevertheless, during the process of the FEM analysis of vehicles, the technologies of building the typical connecting means-welded spots on the car body is the key technology to ensure the correctness and the higher accurate rate of the FEM model analysis results.In this dissertation, in allusion to the limit that the domestic analysis and studies of the body structure only concentrate on the static bend, torsion and some extreme conditions in nowadays and the studies on transient analysis of the whole vehicle that contains the suspension model, tire model and the road model are few, the applications of the FEM on the analysis of the car body structure are studied. And in this dissertation the method of building connecting means models, the dynamic response of the body, the fatigue analysis of the body and the reforming measures of the body are deeply discusses.Firstly, the FEM is applied to study the typical connecting means-welded spots on the car body that has great influence on the correctness rate of the FEM model in the dissertation. Combing the experiment modal of the typical metal sheet, five models used to replace the welded spots are discussed. It is figured out that the models that adopt the same nodes, the brick elements and the single beams elements shows the better consistency with the experiment modal and frequency. Considering the accurate rate of the analysis results and the time cost to build the whole model, it is suggested that the single beams elements are adopted on the car body FEM model. And it could shorten the time to build the body model and ensure the enough accurate rate on engineering.Secondly, the methods to deal with the welded spots in this dissertation are used to build the FEM model of BIW (body in white). The analysis well anatomize with the experimental results, which shows the methods to deal with the typical connecting means is felicitous and the model could be used to analyze the stiffness characteristics and the strength characteristics of the car body structure.