Failure analysis of 3D printed woven composite plates with holes under tensile and shear loading

This paper presents the modelling and failure analysis of 3D printed woven composite plates with a hole under tensile and shear loading. In the finite element (FE) software, woven cells are built using stacking sequences, which are then linked together to form the FE model of the woven laminate. According to the 3D printing experiments, tailored fibre placement is achieved in the simulation by altering the fibre orientation around a region to leave a hole. In order to compare this placement technique with that of a control group, 'drilled' samples with the notch removed via mechanical machining was proposed. Three cases, open-hole laminates under tensile loading and double-shear and single-shear loading, are studied to advance the understanding of the failure mechanisms. Good agreement between numerical and experimental results has been obtained, which exhibits a similar trend of strength improvement using new placement technique. The distribution of principal strain and displacement in the modelling are consistent with the results obtained from Digital Image Correlation (DIC) and Micro X-ray Computed Tomography (Micro-CT). It suggests that the avoidance of fibre breakage and the overlap of printed materials around the hole can dramatically increase the failure strength and prevent the propagation of cracks.