NUMERICAL MODELING OF THERMOMECHANICAL PROCESSES RELATED TO BULK FORMING OPERATIONS

A thermomechanically sound, decoupled model, numerically unified for c old and hot bulk metal forming is cast into a finite element formulati on. The mechanical module is based on elasto-(visco)plastic material c ostitutive laws and general interface frictional contact conditions wi th the assumption of rigid tools. Introduction of a logarithmic strain based finite strain model in the contex of a geometrically nonlinear assumed strain method characterizes the numerical treatment of incompr essibility at large deformations. A non-associated slip rule is employ ed in the contex of the plasticity theory of friction, with nonlinear master segment geometry describing the contact kinematics. Consistent linearisation in all aspects of algorithmic development provides robus t and quadratically convergent solutions. This is shown in 2-D plane s train and axisymmetric numerical examples, where simulations of both c old and hot bulk metal forming processes are performed.