Influence of voids and impact damage on the fatigue behaviour of large scale composites.

Defects in laminated composite structures like voids and impact damages have a major influence on the fatigue behaviour. These defects may occur in the manufacturing process and during lifetime of composite parts and lead to matrix cracks within single layers and to delaminations between adjacent layers with different fibre orientations. We investigated the relationship between voids and impact damage and fatigue lifetime. Specimens made of a glass fibre non-crimp fabric were produced by vacuum assisted resin infusion. Voids were introduced by air-bypass simulating a leakage during the vacuum assisted resin infusion-process. Impact damage was induced using a canon. Stringer-panels with the basic dimensions of 1000 mm × 1200 mm and a radius of 1980 mm were tested under multiaxial load situations in a hexapod test rig and a tension/compression-shear test rig. [ABSTRACT FROM AUTHOR]