Key Laboratory of Materials Processing Engineering;
School of Material Science and Engineering;
Xi'an Shiyou University;
Xi'an 710065;
China;
Key Laboratory of Advanced Manufacture Technology for Automobile Parts(Chongqing University of Technology);
Ministry of Education;
Chongqing 400054;
China;
Bime;
Bremen Institute of Mechanical Engineering;
MAPEX Center for Materials and Processing;
University of Bremen;
Bremen 28359;
Germany;
Deformation behaviors; Four-layered U-shaped bellow; Hydroforming; Numerical simulation; Springback;