Analysis and evaluation of friction effects on mode II delamination testing

In this paper the attention has been focused on the evaluation of how friction can influence Four-point End-Notched Flexure test in carbon fibre-epoxy composite materials. The starting point has been the hysteresis loop in the experimentally obtained Load versus Displacement curve due to an unloading-loading cycle. Different locations for friction have been considered. Numerical simulations have been performed by using Finite Elements and an experimental test campaign has been also carried out to validate the model and to optimize friction coefficients through the comparison with test results. The outcomes of the numerical analysis have given useful indications. Firstly, the comparison of the simulated maximum load and dissipated energy with those coming from the experimental tests has given good results. Secondly, it has been found that the contact between pins and specimens is the most significant location for friction.