Implementation of backward tracing scheme of the FEM for design of initial tubular blank in hydroforming

Tubular hydroforming has been widely applied to the automotive industry recently, and the finite element analysis is rapidly used as an effective tool of evaluation and optimization on designing of hydroforming dies and processes. Successful hydroforming depends on selection of proper tubular blank and sound preform shape as well as reasonable combination of the internal pressure and the axial feeding. In this study, a novel finite element method (FEM) program for the design of preforms in tube hydroforming, which utilizes a rigid-plastic approach and the backward tracing scheme, is constructed with careful numerical treatment of boundary conditions at the die–workpiece interface. This paper also deals with prediction of the initial tube dimensions and intermediate configuration for preform design in hydroforming using numerical simulation by the implicit FEM combined with the backward tracing scheme. The developed program of backward tracing technique is implemented to the hydroforming process in a square and a rectangular die and has been proved to be effective.