The influence of impactor shape on the damage to composite laminates

The post-impact damage properties of composite laminates impacted by various impactor shapes are investigated herein. This investigation is a continuation of the research conducted in [Mitrevski T, Marshall IH, Thomson R, Jones R, Whittingham B. The effect of impactor shape on the impact response of composite laminates. Compos Struct 2005;67(2):139–48]. After impacting thin woven carbon/epoxy laminates using hemispherical, ogival and conical steel impactors all 12 mm in diameter using a drop weight test rig (Mitrevski et al., 2005), various post-impact analysis techniques have been employed, such as non-destructive inspection (NDI) and microscopy to assess the effect of impactor shape on the resulting damage. The blunter hemispherical impactor produced the largest damage area dominated by delamination. The rather sharp conical impactor produced the most fibre breakage which resulted in a localised damage area and the largest indentation/penetration depth. A significant reduction in tensile strength was found for all specimens. The specimens impacted by the hemispherical impactor at 4 J experienced a slightly higher residual tensile strength due to the barely visible impact damage (BVID) induced which was dominated by delamination.