Formability influenced by process loading path of double sheet hydroforming

LIU Wei¹, LIU Gang², CUI Xiao-lei¹, XU Yong-chao¹, YUAN Shi-jian¹

(1. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology,
Harbin 150001, China;
2. Key Laboratory of Ministry of Education for Conveyance and Equipment,
East China Jiaotong University, Nanchang 330013, China)

Abstract:Double sheet hydroforming can be used to manufacture hollow part with complicated section geometries by allowing material draw-in under an appropriate process loading path. Two major parameters, clamping force and liquid pressure, were studied for hydroforming of unwelded double sheets. A proposed limit liquid pressure corresponding to different clamping forces was calculated theoretically, which can be used to reveal the influence of process parameters combination on deformation behaviors. The calculated results were studied and verified by FE analysis and experiments. Two linear loading paths and a multi-step loading path were applied to study the sheet deformation behaviors and formability. The experimental results illustrate that the multi-step loading path shows better formability than other loading paths.

Key words:double sheet hydroforming; clamping force; liquid pressure; formability