Body-in-white lightweight design method based on material characteristics and frame topological structure

The invention belongs to the technical field of mechanical lightweight design, and particularly relates to a body-in-white lightweight design method based on material characteristics and a frame topological structure, which comprises the following steps of: establishing a body-in-white finite element model, determining parts and key variables which need to be optimized, then establishing a body-in-white finite element optimization model, and obtaining a sensitivity sequence of the key variables; selecting a design variable; designing a test scheme, and establishing a multi-objective optimization model; optimizing in the design range to obtain optimization parameters of the design variables meeting the constraint conditions; according to the method, materials with different mechanical properties are selected at different positions of a body-in-white according to stress distribution of the body-in-white, so that material performance and geometric parameters of a topological structure jointly serve as optimizati