Modelling of interlaminar fracture processes in composites using interface elements

The use of interface models for the full simulation of fracture processes in polymer–matrix composites is discussed in the present paper. To this end, a numerical model accounting for both the elasto-plastic behaviour of the material surrounding an interlaminar crack in thermoplastic–matrix composites and the fracture behaviour of the material inside the fracture zone was developed. An attempt to separate decohesion from other main dissipative effects such as plasticization of the matrix has been made. The material behaviour observed by applying a toughening technique known as “interleaving” was explained by the evolution of process and plastic zones in the interlaminar region. An indirect identification procedure of the interface behaviour based on fracture testing of the neat resin was proposed, but the agreement with the experimental composite response was not completely satisfactory.