In this paper, the low velocity impact (LVI) on a shear dominated composite laminate with stacking sequence [45/0/-45/90]_(3s) has been investigated experimentally and numerically. The stacking sequence is specifically designed such that each interface would have a ply angle difference of 45° between the upper and lower adjacent plies, providing a shear dominated damage behavior with respect to delamination. Drop-tower tests are carried out with the impact energy of 25J and an impactor mass of 7.5Kg. 3D digital image correlation (3D) is done to measure the in-situ deformation of the specimen bottom surface. Nondestructive inspections (NDIs) including ultrasound C-scanning and X-ray based micro-CT are performed to characterize the internal damage after the LVI event. A continuum shell based finite element (FE) model has been applied to predict the LVI event, in the sense of load-time and load-displacement responses, and damage modes including fiber breakage, matrix splitting and delamination. The intra-ply damage mechanisms are modeled using Enhanced Schapery Theory (EST) and the inter-ply damage mechanism is based on defining cohesive contact behavior between plies. FE predictions are compared against experimental findings and good agreement, especially in terms of detailed ply-by-ply damage patterns, are obtained. Further discussion on the interactions between damage modes in LVI events are provided with the help of post-impact micro-CT images and numerical results.
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