Analytical study of delamination damage and delamination-free drilling method of CFRP composite

Abstract Drilling of composite materials is a challenge in aviation and aerospace field. Delamination often occurs at the hole exit which can reduce the strength of the structure. In this study, to reduce delamination, an analytical model with thermal effect is proposed to predict critical delamination condition of composite. Anisotropy of the composite, thermos-mechanical deformation and load cases of the tool are taken into consideration. Numerical simulation and punching experiments with accurate uncut plies are conducted to validate the rational of the analytical model. The value of critical thrust force and the effect of drilling temperature on that are obtained from the model. In addition, a thrust force model based on the tool geometry is presented with the feed rate per tooth. According to the proposed model, critical feed rate per tooth for delamination-free drilling with different uncut plies and drill diameters can be obtained