Fatigue Analysis And Structural Optimization On Stamping Die Of Advanced High Strength Steels

The extensive application of advanced high strength steels in auto bodymanufacturing is one of the main ways to reduce the body weight. Compared with thetraditional high strength steel, high strength steel has higher strength and goodformability. It is beneficial to reduce the vehicle weight and improve the security,while it also brought in new challenges on motor dies strength and fatigue.Stamping die of advanced high strength steels require higher forming force.Working conditions of stamping die become even worse. Fatigue damage is easy toproduce because of the long-term cyclic and high impact loading. Die failure resultfrom fatigue damage not only will affect the quality of products, but also cause thewaste of materials and working hours. Furthermore, it leads to low efficiency andcosts increase.To solve this problem, a method of FEA with the combination of DYNAFORMand ANSYS/LS-DYNA was investigated to stress analysis of stamping die. The FEAresult showed the stress state on the stamping die during dual-phase steelCR780T/420Y-DP drawing process. According to the results of FEA, the stress ondifferent parts of stamping die is uneven distribution and rapid changes in parts ofsection of stamping die have larger equivalent stress.Fatigue analysis is based on the result of stress analysis. Binder and die are themain objects of fatigue analysis. The Fatigue life of stamping die could be predicted.The result shows that the life of stamping die could meet the basic designrequirements. However, there may be additional production tasks in the production ofparts. In order to meet the requirements of additional tasks, life of stamping die needto be enhanced.To solve this problem, further optimization for the binder was also conductedbased on FEM simulation and engineering experience. The result shows that there issmaller stress on the optimized binder structure and the fatigue life was enhanced.All these work provides an effective way to support strength checking andstructure optimization of stamping die of advanced high strength steels.