Physically based models of metal plasticity

Abstract: This work is focussing on the material modelling aspects in simulation of forming processes. The research question is: Do physical based material models have any advantages compared to the more common type of engineering models used in simulation of forming processes? The success of performing useful simulations of forming processes depends very much on the accuracy of the used material description. The thesis deals with the material modelling process that includes choice of model, parameter optimisation and implementation of constitutive routine into finite element code. User routines have been implemented into the ABAQUS code together with predictions of forming limit diagrams for sheet metal forming. This was applied to a forming case using a dislocation density model. A toolbox in Matlab has also been developed for optimisation as well as testing of constitutive routines. The work concerning physical based material models has focussed on models based on dislocation density as a variable to describe the hardening and softening of the material. A literature review has been the basis for choice of models. The models have been tested for real, engineering data obtained from the material manufacturers. The licentiate thesis consists of three conference proceedings.