| With the continuous development of the automotive industry, the requirements of consumers and enterprises for the safety of cars are also getting higher and higher. As a main part of the car body, the car roof plays an important role in maintaining the structure of a car and protecting the safety of the occupants. The safety of the roof contributes a lot to the safety of the car. When the distribute load, represented by snow, or the roof pressure in the rollover accident was put on it, the structure of the roof will produce corresponding changes and directly affect the performance of the vehicle. Therefore, it is very necessary to study the performance of automobile roof.In this thesis, the snow load performance and the roof crush resistance performance of the vehicle roof are studied, taking an SUV as an example. First of all, the evaluation indexes and common analysis methods of automobile roof are studied, and the research methods and technical means of analysis work are determined. Then, based on the CAD model, an accurate finite element model is established and the different load and constraint conditions are applied to it, which makes preparation for the finite element analysis.Based on the shell stability theory and buckling analysis theory, the vehicle’s snow load performance is analyzed. The non-linear buckling analysis is done under critical buckling load, which is determine by the linear buckling analysis. In the vehicle roof snow load test, the deformation data of the top cover at all levels are recorded and compared with the simulation results. According to the FEA and experimental results, four optimization schemes are proposed and the best one is put out according to the analysis results comparison.Referring to domestic and foreign roof strength standards, the vehicle rolling mechanism and stress conditions of the main bearing components of roof are analyzed. The contribution of the main bearing components to the roof compression strength is determined according to the analysis results and three optimization schemes are proposed for the main components. The results show that the compression performance of the optimized roof is increased by 18.10%,33.94% and 9.05%. |
