Tensile failure of open-hole composite laminates with yarn gaps: Experimental and numerical study

The tensile mechanical behavior and failure mechanism of multidirectional carbon-fiber-fabric-reinforced open-hole composite laminates were investigated in this study. Using digital image correlation (DIC) technology, test specimens were subjected to quasi-static tensile tests to determine their macroscale mechanical properties. An analytical framework was developed to predict the tensile properties, damage evolution, and failure mechanisms of the open-hole composite laminates. Two types of finite element (FE) models: mesoscale model and macroscale-equivalent model, were established. The mesoscale model considers the coupling effect of the yarn gaps and central circular hole. An Abaqus subroutine was written to introduce the Hashin failure criterion, considering the stiffness degradation. The fracture morphology was examined by scanning electron microscopy (SEM) to determine the failure mechanism of the specimens. The results show that the average ultimate load of the specimens is 27.2 kN. The errors predicted by the macroscale-equivalent and mesoscale models are 5.5 % and 1.5 %, respectively. The mesoscale FE model accurately simulated the damage evolution process of each layer under the coupling effect of the yarn gaps and central circular hole. The simulation results and SEM images showed the different failure modes of the fiber layers at different angles.