Analytical Sensitivity Analysis Method of Cross-Sectional Shape for Thin-Walled Automobile Frame Considering Global Performances

Abstract

At the conceptual design stage, thin-walled beams (TWBs) with the complex cross-sectional shapes are extensively used to compose the automobile frame. Thus, the performances of automobile frame are determined by cross-sectional shapes of TWBs. Currently, the modifications of complex cross-sectional shapes depend on the experience of engineers, which often causes the design risk. Meanwhile, to our knowledge, the previous studies mainly focused on the regular cross sections and paid little attention for the complex cross-sectional shape for the automobile frame. Therefore, this paper proposes an analytical sensitivity analysis method to modify the complex cross-sectional shapes. This method regards the coordinates of points and the thicknesses of sheets as design variables to describe the cross-sectional shapes. The bending stiffness, torsional stiffness and frequency are used to evaluate the performances of automobile frame. Finally, an example of the RAV4 automobile frame verifies that the analytical sensitivity analysis method can effectively guide the modification of the cross-sectional shape and achieve the lightweight automobile frame.