Artificial hail ice impact damage of laminated composite T-joint with stitching reinforcement

Hailstone impact has been one of the major concerns in the design and analysis of composite aerospace structures. Being key elements of such structures, T-joints with stitching reinforcement are investigated in this paper to understand its failure response in artificial hail ice impact loading conditions. Artificial hail ices are projected to the skin of composite T-joints at different energy levels with gas gun. High speed camera is used to capture the failure process of artificial hail ices. Quasi-static pull-off test is applied to assess the residual tensile strength of stitched and unstitched T-joint. Delamination damage has been observed on specimens after ice impact test, and the pull-off load capacity has been affected as well. It is found that hail ice impact can cause delamination damage to different regions and have influence on the failure mode and load capacity of T-joints in pull-off tests. Stitching has been found efficient in resisting the propagation of delamination, and can improve the ultimate displacement and load of T-joints remarkably.