Prediction of threshold impact energy for onset of delamination in quasi-isotropic carbon/epoxy composite laminates under low-velocity impact

This paper describes a procedure for the prediction of the threshold impact energy for the onset of delamination in fibre-reinforced quasi-isotropic laminates under low-velocity impact. It is primarily based upon two models. One is the energy-balance model which equates the kinetic energy of the impactor with the static deformation energy of the laminate. The geometrical non-linearity of the deformation of the laminate is also taken into account. Another model is the force-driven model previously proposed by Davies and Zhang. The combination of these two models forms a simplified and straightforward procedure for the prediction of the threshold impact energy for the onset of delamination without relying on a time-consuming dynamic analysis. The theoretical prediction is compared with experimental data for laminates of various sizes and boundary conditions. Good agreement is observed for all the cases under consideration.