Backward tracing simulation of precision forging process for blade based on 3D FEM
(1.四川大学 原子与分子物理研究所，成都 610065
2.西北工业大学 凝固技术国家重点实验室，西安 710072
3.State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology,Huangzhong University of Science and Technology, Wuhan 430074, China)
2.西北工业大学 凝固技术国家重点实验室，西安 710072
3.State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology,Huangzhong University of Science and Technology, Wuhan 430074, China)
Abstract: In order to obtain the desired final shape, the blade precision forging requires a reasonable preformed billet which can be obtained from a given final shape by using backward tracing scheme based on FEM. The key technologies of backward tracing scheme based on 3D rigid-viscoplastic FEM were explored, and some valid algorithms or methods were proposed. A velocity field was generated by combining the direct iterative method with Newton-Raphson iterative method, and then the initial velocity field of backward tracing simulation was achieved by reversing the direction of the velocity field. A new method, namely the tracking-fitting-revising method, was proposed and can be used to determinate the criterion of separating a node from die in the backward tracing simulation. The ceasing criterion of the backward tracing simulation is that all the boundary nodes are detached from dies. Based on the above key technologies, the 3D backward tracing simulation system for the blade precision forging was developed, and its feasibility and reliability were verified by forward loading simulation.
Key words: blade precision forging; preform design; backward tracing scheme; FEM