Combined finite element-boundary element thermo-mechanical analysis of metal forming processes

This paper presents an innovative approach for obtaining the distribution o f temperature in the dies during thermo-mechanical numerical analysis of me tal forming problems. The proposed approach is based on a solution resultin g from the combination of the finite-element method with the boundary-eleme nt method. The finite-element method is used to perform the thermo-viscopla stic modelling of the deforming workpiece, while the boundary-element metho d is applied for computing the distribution of temperature in the dies. Hea t transfer between the dies and the workpiece, is analysed using the finite -element solution of the heat flow across the die-workpiece interface to de fine the boundary conditions to be applied on the thermal analysis of the d ies. The transfer of boundary conditions is performed using an adaptive bou ndary-element generator that continuously redefines the elements limiting t he contour of the dies in the contact interface with the deforming workpiec e. A numerical example consisting of the axisymmetric thermo-mechanical mod elling of an industrial closed-die forging operation is included to show th e applicability of the proposed approach. (C) 1999 Elsevier Science S.A. Al l rights reserved.