A numerical-experimental study of the damage response of stitched composite laminates to low-velocity impact

This study examines the effect of stitching on the structural and damage response of [03/903]s and [0/90]3s carbon/epoxy laminates subjected to low-velocity impact. The commercial finite element code Abaqus was used to model the laminates and to simulate the progression of the internal damage under impact. Intralaminar (fibre breakage and matrix fracture) and interlaminar (delamination) damage modes were introduced in the simulations of the stitched and the unstitched plates by the use of energy-based continuum damage models. The results of the FE simulations were compared with the force-deflection data and the damage maps obtained experimentally by radiographic analyses. The numerical results are in good agreement with the experimental observations, both in terms of structural response of the laminates and of shape and size and of internal damage.