Metal-forming problems with combined hardening

摘要

A class of quasi-steady metal-forming problems under nonlocal contactand Coulomb's friction boundary conditions is considered with an incompressible,rigid-plastic,strain-rate dependent,isotropic,and kinematic hardening material model.Acoupled variational formulation is derived,the convergence of a variable stiffness parame-ter method with time retardation is proved,and the existence and uniqueness results areobtained.