The layout and fatigue life analysis of welding spots for the cab body in white of a commercial vehicle

The finite element model with shell element for a commercial vehicle cab body in white is set up. In order to optimize the layout of welding spots, topology optimization with single objective is conducted first. After analysis of the optimization results, we get the conclusion that topology optimization with single objective can not meet various performance requirements of automotive body. Then the multi-area synthetic optimization method is used for the welding spots layout optimization. Considering the different influences of the cab components to the stiffness, strength and low modal frequency, the cab is divided into two different areas. Based on the stiffness and strength analysis results, the layout of welding spots in the area which has larger influence on the stiffness, strength and low modal frequency is adjusted. And topology optimization is applied in the other area for the layout optimization of welding spots. The synthetic optimization result is obtained by integrating optimization results of the two areas. The fatigue life of welding spots for the optimized and the original models are analyzed. The comparison of results indicates that the optimization methods used are rational and effective.