热成型钢电阻点焊热影响区精准建模技术OA

For severe deformation conditions,the thermal affected zone of resistance spot welding in hot-formed sheet metal is prone to failure during collisions.In structural collision simulation analysis,it is essential to accurately model the thermal affected zone to achieve high-precision predictions of the overall vehicle′s collision performance.A study is conducted on the fracture behavior of the base material(1500HS)for hot-formed steel plates.Various notched specimens are designed,and material mechanical performance experiments are carried out.The mother material′s fracture surface for the Modified Mohr-Coulomb(MMC)model is obtained through fitting failure strains based on different stress states.Subsequently,the generalized incremental stress-state dependent damage model(GISSMO)failure curve is generated under plane stress conditions.Additionally,tension failure specimens for resistance spot welding are designed.The failure parameters of the thermal-affected zone are determined based on the parent material′s mechanical properties using a reverse calibration method.To verify the accuracy of the research results,a drop-hammer experiment is designed for hot-formed steel plate hat-section beams.The dimensions of the spot welds on the hat-section beams are 6 mm with a 30 mm spacing between weld points.Through comparative analysis,it is demonstrated that the precise modeling method for the thermal-affected zone of resistance spot welding can meet the dual precision requirements for impact acceleration and displacement,thus fulfilling the engineering requirements for structural safety development.