Automobile frame optimization design method

The invention discloses an automobile frame optimization design method, which comprises the following steps of: S1, establishing a beam unit model frame and a shell unit model frame, finishing pretreatment, and respectively calculating initial values of basic performance parameters; s2, performing multi-target topological optimization on the beam unit model frame, and determining structural arrangement and section size; s3, size optimization is conducted on the beam unit model frame, whether the optimized structure is reasonable or not is judged, if not, the unreasonable local area structure is removed, the step S2 is executed again, and topological optimization is conducted on the unreasonable local area again; s4, establishing a three-dimensional model of the optimized frame, determining whether the manufacturability is feasible or not, and if not, returning to the step S3; s5, establishing an optimized rear shell unit model frame, and performing fine design; s6, size optimization is conducted on the shell