This invention discloses a
topology optimization design method for hot-formed steel automotive main frame welded tubes, comprising: establishing an initial model of the automotive main frame welded tube, the initial model including an installation area, a central load-bearing area, a collision
energy absorption area, a weld candidate area, an optimizable area, and a non-design area; performing
topology optimization on the optimizable area to obtain
material density distribution results; dividing the area into high-density, medium-density, and low-density areas based on the
material density distribution results, and determining the collision
energy absorption area based on the collision deformation trend; converting different areas into stiffeners, locally reinforced structures, variable cross-section transition structures, cross-section reduction areas, and induced crushing structures, respectively; determining the longitudinal weld position based on
stress distribution and collision deformation trend; compensating and correcting the structural parameters according to the hot forming process, and outputting a design scheme for the hot-formed steel automotive main frame welded tube. This invention can improve material utilization, weld reliability, and hot-
formability manufacturability.