Abstract Advanced high strength steels (AHSS) are increasingly used in various industrial applications for complex sheet metal channels, but the higher strength, variable cross-sections and local features pose great challenges to forming processes. This work numerically investigates the feasibility of the roll-stamp forming technique for manufacturing AHSS channels with variable cross-sections and local features. The forming target is a typical vehicle sill component, characterized by significant cross-sectional variation and complex local features (one of which is similar to the T-node of the benchmark case). Die block sets and a finite element model of the roll-stamp forming process are developed and implemented. The material is QP1180 and the Hill’s 1948 yield criterion coupled with the Chaboche hardening model is established to describe the anisotropy and Bauschinger effect. The simulation results show that roll-stamp forming of the demonstrative sill is successfully achieved. The residual stress is generally low and mainly concentrated on the local features, with the maximum value below 600 MPa. The max principal strain is evenly distributed along the longitudinal direction, with the higher level of strain similarly localized around the local features. Furthermore, the formability is further evaluated using the forming limit diagram (FLD), which suggests a low risk of crack defects. The comparison of the forming load in stamping and roll-stamp forming verifies the latter’s advantage in reducing forming load. This work demonstrates that the roll-stamp technique provides an effective approach to form complex AHSS sheet metal channels.
Zhang et al. (Mon,) studied this question.