The effect of tow gaps on compression after impact strength of AFP laminates

When Automated Fibre Placement (AFP) is used to manufacture aerospace components with complex three dimensional geometries, gaps between fibre tows can occur. This paper explores the interaction of these tow gaps with impact damage. Impact of two coupons containing tow gaps shows that the area of delamination is smaller for an impact directly over a tow gap where the tow gap lies close to the non-impact face. Compression After Impact (CAI) testing shows that both the formation of sublaminate buckles and subsequent growth of delaminations is inhibited by the presence of a tow gap near the non-impact face. Non-destructive testing techniques and a computationally efficient infinite strip model are used to analyse the damage resistance and damage tolerance of the coupons.