Thermoelastoplasticity applied to T-shaped tube hydroforming optimization

Abstract

Hydroforming simulation of T-shaped tube is performed using an thermoelastoplastic model implemented in Forge-2005 c (fully implicit FEM code). A thick cylindrical AA-6060-T4 aluminium alloy tube is inflated in a T-shaped die. A third tool limits the material flow in the central branch during loading. An iterative scheme is used to obtain the load path. A three dimensional case of T-shaped hydroforming is proposed. This work studies the sensitivity of the process regarding to crucial parameters like, die/tube friction, tools kinematic, die radius, inner pressure law and material hardening. Impact on thickness repartition and plastic strain in the finale part is studied. An improved load path is proposed regarding to those aspects. In the same time the position and size of potentially dangerous zones regarding to plastic instability or damage are checked. Looking to the gradients of plastic strain and triaxiality σ hydro /σ mises through the thickness, the interest of a 3D continuum damage tool to predict formability is enlightened.