关键词: 自由弯曲技术, 解析法, 回弹预测, 数值模拟:塑性加工

Abstract: In finite element simulation,To overcome the problem of the dynamic explicit algorithm cannot obtain the exact springback value of the arc section S2 In finite element simulation and the analytical method ignores the characteristic of variable curvature in the transition section S1.To overcome these problems,a solving method of combined analytic method and Finite Element Method (FEM) simulation method was proposed to predict the springback value of the tube made by free bending technology.The simulation process of the tube forming and springback in transition section S1 was completed by explicit and standard algorithm respectively.The springback prediction model in transition section S1 was established by introduce introducing the Moving Least-Squares Methods (MLS) to fit the springback value.Meanwhile,an analytic model is was proposed by considering compressive stress caused by axial pushing force to predict the springback value of arc section S2.Results showed that the springback occurred in the transition section S1 mainly,and the springback value of transition section S1 took  a small portion of the tube.Compared with two experimental results,the error of springback angle between the proposed method and experimental  was 15.09% and 14.76%,and the error between traditional method (the curvature of transition section S1  was taken as constant) and experimental was 27.68% and 24.32%,the prediction accuracy of the springback angle was improved by 11.08%.

Key words: free bending technology, analytical method, springback prediction, finite element simulation, plastic forming