Study on twist defect of thin-walled components with asymmetric section during roll forming

With the development of lightweight technology, advanced high strength steel (AHSS) had been widely used in automotive and construction industry. However, twist defect restricts the application of thin-walled components with asymmetric section. In this work, AHSS MS1500 was taken to investigate the complex non-linear elastoplastic behaviors and twist defect in roll forming process. Finite element analysis (FEA) model was established by COPRA software and the material model considered Young’s modulus variation with plastic deformation and material anisotropy was selected. With the developed model, the mechanism of twist defect was discussed and the effect of forming strategy on twist defect was analyzed. For asymmetric hat channel steel, the asymmetric residual longitudinal stress is the principal reason for twist defect. Loading patterns have a significant effect on twist defect and the developed UDT-type (USTB-Durable-type) method can control twist defect effectively. This study has provided theoretical and technical support on large-scale application of AHSS.