A 2-LEVEL ITERATIVE FEM TECHNIQUE FOR RIGOROUS SOLUTION OF NONLINEAR-INTERACTION PROBLEMS UNDER LARGE DEFORMATIONS

Various problems arising in applied mechanics involve interaction betw een two bodies having separation, bonding, re-bonding and slip at the interface. Simple FEM models assume one of the two extremes, ''bonded interface'' or ''smooth interface''. Alternative spring models have be en developed to model slip, shear strength and dilation. These models are applicable for small deformations and coincident nodes at the inte rface. The paper describes a rigorous solution for the problem which d oes not sacrifice the simplicity of the FEM approach. In this study th e deformations are assumed to be large enough to change the geometry o f the problem and the interface is assumed to be a frictional adhesive one with a coulomb failure criterion. The technique examines the inte raction of two bodies, namely the slave and master bodies. It simulate s frictional slip, separation, bonding and re-bonding of the slave bod y with respect to the master allowing for large deformations and non-m atching nodes at the interface. The proposed solution is iterative whe re two levels of iterations are used. The first iteration procedure is used to satisfy equilibrium and to deal with the geometrical non-line arity, while the second is used to satisfy the interaction conditions at the interface. The proposed technique is illustrated with a number of test problems of varying complexity. These demonstrate that the app roach performs well for problems involving interaction of two bodies u nder large deformations. Copyright (C) 1996 Elsevier Science Ltd.