Finite element analysis of tube inversion process with radiused dies

Abstract

The extended r_min technique has been incorporated in the incremental updated Lagrangian formulation (ULF) of an elasto-plastic finite element computer code in order to handle the contact boundary condition when analyzing the axisymmetric tube inversion process with a quarter fillet die radius. A fillet die applies an axial compressional load onto a thin tube so that the inside or outside of the tube inverts totally making the central axis of the original tube the same as a new double-walled tube. This is called an inside-out or outside-in inversion process. This study employs an elasto-plastic finite element method to simulate and analyze inside-out inversion. The objective is to examine how different process factors, such as the geometry and material modulus, influence metal tube inversion. This study also simulates a quarter fillet radius of the die to analyze the tube forming condition and range that can be applied in engineering under these requirements. In addition, the axial compressional load under inside-out inversion stability to be suitable for a personal computer, so it can be effectively analyzed and evaluated on line instantaneously.