A progressive damage model for mechanically fastened joints in composite laminates

A three-dimensional finite element model is developed to predict damage pro gression and strength of mechanically fastened joints in carbon fibre-reinf orced plastics that fail in the bearing, tension and shear-out modes. The m odel is based on a three-dimensional finite element model, on a three-dimen sional failure criterion and on a constitutive equation that takes into acc ount the effects of damage on the material elastic properties. This is acco mplished using internal state variables that are functions of the type of d amage. This formulation is used together with a global failure criterion to predict the ultimate strength of the joint. Experimental results concernin g damage progression,joint stiffness and strength are obtained and compared with the predictions. A good agreement between experimental results and nu merical predictions is obtained.