On the debonding in multilayered composite structures. A new numerical approach

In the present paper, the behavior of multilayered structures glued by an a dhesive material subjected to cleavage loading is investigated. The adhesiv e material is assumed to obey to a nonmonotone, multivalued reaction displa cement law in three dimensions. This kind of behavior observed as result of the development of technology, leads to a variational expression for the p rinciple of virtual work called hemivariational inequality which is equival ent to a substationarity problem; the latter is a generalization of the pri nciple of minimum potential energy of the multilayered composite structure taken into account the possibility of debonding along the glued interfaces. The solution of this inequality expresses the substationarity principle fo r the potential energy of the structure. The solution of the problem is ach ieved by the application of the NSOLIB algorithm, which is based on the pro ximal bundle method. By means of this algorithm, one at least substationari ty point is obtained (e.g. at least one of the local minima or saddle point s). The effectiveness of the proposed method is illustrated by means of num erical examples.