The responses and damages of graphite/epoxy composite laminates subjected to low-velocity impact are studied through a three dimensional finite element method and experiment. In the finite element analysis, an 8-node brick element with incompatible modes and Newmark constant-acceleration time integration scheme are employed. A modified Hertz contact law between a sphere and a composite laminate is incorporated to determine the impact force. When the deflection of plate reaches to maximum value, damage analysis is performed using static Tsai-Wu failure criterion. The calculated failure contour at back surface of laminate is in good agreement with the delamination area detected by C-scan. The effects of stacking sequence on damage are discussed for various impact energy levels.
