Three-dimensional adhesive contact laws with debonding: a nonconvex energybundle method

In the present paper we develop a new numerical approach to the problem of structures having two or more parts of them adhesively bonded together like e.g. in sandwich structures. The adhesive material is idealized by a nonmo notone, possibly multivalued stress-strain law, which is three-dimensional (3D) and introduces a nonconvex nonsmooth energy function in the problem. T he problem is formulated as a hemivariational inequality, whose solution(s) must render the potential energy substationary. We apply here thr proximal bundle method and more specifically the optimization programme NSOLIB, bas ed on first order polyhedral approximations of the locally Lipschitz contin uous objective function. This algorithm permits the determination of at lea st one substasionarity point, e.g. of an equilibrium problem. An example of a 3D finite element model, illustrates the effectiveness of the proposed m ehod. (C) 2000 Elsevier Science S.A. All rights reserved.