Prediction of plastic strain accumulation in continuous fiber reinforced laminates by a constitutive ply model

The present paper is concerned with the prediction of plastic ply strains which accumulate in continuous fiber reinforced laminates with polymeric matrix materials. The study is based on a constitutive model which is implemented within the Finite Element Method. Plastic strains are expected to evolve when the ply is subjected to a pronounced shear load and/or to pronounced transverse compression. Two plasticity mechanisms are modeled at ply level under plane stress assumption (i.e. for thin shells and plates). They either concern the evolution of plastic shear strains or the evolution of plastic normal strains. The proposed plasticity model is combined with an existing ply level continuum damage model. The capabilities of the proposed model are assessed by comparing its predictions to experimental data from literature. Emphasis is placed on loading conditions which drive the evolution of plastic strains. Excellent correlation with experimental results is shown for proportional as well as for non-proportional ply loadings.