A FIELD BOUNDARY-ELEMENT FORMULATION FOR DAMAGE MECHANICS

In this paper, two typical and representative elastoplastic damage mec hanic models are presented in the context of a field boundary element formulation. In particular, the damage models of Lemaitre and Gurson a re considered. Lemaitre's model is based on more phenomenological cons iderations, whereas Gurson's model describes the failure mechanism on a micromechanic level by means of initiation, growth and coalescence o f voids. The special requirements of implementing both models into a h eld boundary element code are investigated. The formulation is based o n thermodynamics of irreversible processes and the concept of internal variables. Kinematic and isotropic hardening, isotropic damage evolut ion and arbitrary uniaxial stress-strain relations are considered to d escribe the nonlinear material behaviour at small strains. The theoret ical background of both models as well as the field boundary element f ormulation are presented. This includes the evaluation of hypersingula r boundary integrals and a consistent regularization of strongly singu lar domain integrals for arbitrary domain elements. The strain-space f ormulations of the constitutive equations are presented first in 3D an d then applied to 2D examples, in order to demonstrate the validity of the proposed method. (C) 1997 Elsevier Science Ltd.