STEADY-STATE FINITE-ELEMENT ANALYSIS OF COLD FORWARD EXTRUSION

Finite-element analysis of metal forming processes is treated predomin antly by the Updated Lagrangian formulation in which the mesh moves an d deforms in space, in accordance with the deformation history of the material. However; the steady-state deformation characteristics of som e metal forming processes such as extrusion, drawing and rolling, can be analysed advantageously using an Eulerian formulation in which the finite-element mesh is fixed in space. Extension of the latter to incl ude work hardening material response can be accomplished through the u se of a combined Eulerian-Lagrangian formulation. Such extension is ba sed on the utilisation of an Updated Lagrangian temporary mesh, to cal culate the strain and stress fields, coupled with a mathematical schem e to interpolate the strain and stress tensors into the Eulerian mesh, in order to determine the new distributions at the fixed mesh positio ns. An example of steady-state cold forward rod extrusion is analysed using both the Updated Lagrangian and the combined Eulerian-Lagrangian formulations. Comparisons are made between the theoretical finite-ele ment predictions and experimental data obtained through the utilisatio n of visioplasticity and micro-hardness techniques.