Multiscale Experimental and Simulation Insights Into Flexural Damage Mechanisms and Porosity Sensitivity of 3D Orthogonal Woven Composites
Abstract
This study uses multi‐scale experiments and high‐precision predictive simulations to reveal the bending failure mode and porosity sensitivity of three‐dimensional orthogonal woven composites (3DOWC). X‐ray computed tomography (CT) and metallographic analysis yielded average porosity (1.78%) and yarn geometric parameters. A high‐precision predictive macroscale finite element (FE) model was built using TexGen and a custom Python script. A user‐defined material subroutine (VUMAT) with the 3D Hashin criterion simulated yarns' elastic anisotropic response and progressive damage. The model was validated by digital image correlation (DIC), scanning electron microscopy (SEM), and bending tests. At 3% porosity, bending performance deteriorated: weft failure strain dropped 19.05%, maximum load and strength dropped 21.55%, and warp flexural modulus dropped 13.28%. Moreover, voids concentrated at the mid‐span region cause more severe degradation than those near the support ends, highlighting the location sensitivity of porosity effects. Simulations revealed that microstructures in primary load‐bearing yarns may induce delamination failure. This framework aids material optimization, such as by embedding high‐performance fibers in high‐stress zones.