|Title: Influence of ply thickness on the fibre matrix debonding: 20th International Conference on Composite Materials (ICCM 20)|
|Written by: Leopold, C. and Liebig, W. and Harder, S. and Fiedler, B.|
|Address: Copenhagen, Denmark|
Abstract: In this work, the influence of ply thickness in the 90° layer in cross-ply laminates on the initiation of fibre matrix debonding and inter-fibre-fracture under tensile loads is investigated experimentally by using model composites as well as in a FEM simulation. Decreasing the ply thickness leads to a shift of the onset of inter-fibre-fracture to higher loads. The failure propagation at higher loads is less severe with decreasing layer thickness. Explanations for this behaviour like the probability of a critical defect in the reduced volume or the in-situ effect are discussed. The FEM model is able to represent the ply thickness effect and simulation results are qualitatively in good agreement with the experiments. In the simulation, first fibre-matrix-debonding was found at higher global strain and matrix cracks were more but less severe for thinner plies, whereas an earlier damage onset and fewer cracks, running through the whole layer thickness are found for thicker layers. A reduction of ply thickness in cross-ply laminates increases the resistance against inter-fibre-fracture and failure propagation.