Spring-Back Analysis Method Considering the Die Deformation Due to the Stamping Pressure of the Ultra-High Strength Steel

Abstract This paper proposes a spring-back analysis method for investigating the effect of the stamping pressure on the final shape of a B-pillar outer panel manufactured with the ultra-high strength steel. The conventional sheet metal forming simulation of the B-pillar outer panel was conducted with rigid tool surfaces and a deformable blank of CR1180TRIP. Press and die structure was modelled with three dimensional tetrahedral solid elements for the structural analysis. The stamping pressure obtained from the forming simulation was mapped to the tool surfaces in the tool structure model. From the implicit structural analysis, the deformation amount of the press and die structure was investigated quantitatively. The structural analysis method was verified by comparing the total stamping force of rigid surface model and deformable tool structure model. Finally, the conventional sheet metal forming simulation with modified rigid tool surfaces was conducted to investigate the effect of the tool deformation on spring-back. The simulation result shows that the deformation amount due to the stamping pressure can have significant effect on the final product shape.