WU Xin 1,2 , WEN Gui-lin1, HE Li-ping 1 , XU Hui-dong 1 , WEI Ke-xiang 2
(1.State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan Univ, Changsha, Hunan 410082,China;2. School of Mechanical Engineering, Hunan Institute of Engineering , Xiangtan, Hunan 411104,China)