Abstract:
In this paper, both experimental and numerical analysis methods were combined to investigate the effects of resin-missing defects on the flexural bearing capacity and failure process of L-shaped composite laminates. In experiment, resin-missing defects were introduced by spread release wax on the fiber reinforcement and L-shaped laminates was fabricated by vacuum-assisted resin infusion molding process. Bending tests were conducted to analyze the influence of resin-missing defects. In numerical analysis, a three-dimensional finite element model of the L-shaped laminates within resin-missing defects was developed, where Hashin failure criterion and cohesive zone method were used to simulate the intra- and inter-laminar failure. The influence mechanism of resin-missing defects on laminate failure behavior were explored. The experimental results demonstrate that resin-missing defects significantly reduce the bearing capacity of L-shaped laminates and alter the damage propagation paths. Specifically, the damage mode shifts from a main crack propagation in the mid-region of defect-free laminates to a multi-layer dispersed propagation in the defected ones. The numerical simulations reveal that stress concentration caused by the resin-missing defects triggers the premature failure. The local damage subsequently changes the redistribution of local stresses, leading to multi-delamination in surrounding layers. The location of resin-missing defect plays a significant role on the influence of bearing capacity. The middle layer location has greatest influence, followed by inner location, while outer layer defect shows the least impact. This study provides valuable insights into the damage behavior, safety assessment, and damage tolerance design of L-shaped laminates within resin-missing defects.