Multiscale Tensile Failure Mechanisms in Multiaxial 3D Woven Composite Joints: Experimental and Numerical Insights

ABSTRACT The growing utilization of three‐dimensional (3D) woven composites in aerospace applications has heightened the importance of understanding their pin connection behavior for structural design. This study investigates the mechanical performance of pin joints fabricated from two multidirectional three‐dimensional angle‐interlock woven composites (M3DAWC) and a conventional three‐dimensional angle‐interlock woven composite (3DAWC). Tensile testing coupled with post‐fracture computed tomography (CT) scanning was performed to characterize the failure mechanisms of each joint configuration. A multiscale finite element model (FEM), incorporating both macroscopic and mesoscopic features, was developed to simulate the progressive damage behavior under loading. Experimental and numerical results demonstrate that incorporating bias yarns into 3DAWC significantly reduces stress concentrations around the hole region, leading to simultaneous improvements in both tensile strength and failure displacement.