Compressive strength of composite laminates following free edge impact

Barely Visible Impact Damage (BVID) can occur when laminated composite material is subject to free edge impact loads in the plane of the laminate and can result in a significant reduction in compressive strength caused by buckle-driven delamination. This paper will report on a semi-analytical fracture mechanics model that predicts the Compression After Impact (CAI) strength of composite laminates subject to in-plane free edge impact. Compression testing has been undertaken on three impacted coupons in order to validate the theoretical results. Analytical results are shown to be on average within 10% of experimental values for the strain at which propagation of damage occurs.