Damage tolerance analysis of NCF composite sandwich panels

This paper concerns development and validation of impact damage representations in carbon fibre non-crimp fabric reinforced face sheets for damage tolerance analysis of sandwich panels loaded in compression. For this purpose, experimental data accompanied by fractographic observations have been employed to scrutinize numerical predictions by state-of-the-art notch strength models. As a result, equivalent hole representations of visible impact damage (VID) and, more surprisingly, of the subtle barely visible impact damage (BVID) are recommended for reliable damage tolerance prediction of the compression after impact (CAI) load case for the investigated panels. This recommendation relies on the identification of the mechanisms controlling failure resulting in reliable damage tolerance predictions employing a linear cohesive zone model.