Fiber architecture effect on tensile and compressive damage mechanisms of 3D angle-interlock woven composites

Due to the intricate fiber architecture of 3D textile composites, understanding their failure mechanisms presents a challenge. Here we experimentally studied the quasi-static tensile and compressive properties of 3D angle-interlock woven composites (3D AWC) under both warp-loading (AWC-warp) and weft-loading (AWC-weft). Damage morphologies and mechanisms were examined using optical microscopy and X-ray computed tomography. In order to demonstrate the effect of fiber architecture, the results were combined and compared with that of unidirectional (UD) composites with the same total fiber volume fraction (FVF). The fiber architecture effects in 3D AWC can be manifested as the on-axis FVF dependency and fiber undulation influence. When on-axis load-bearing fiber is undulating-free, the difference in mechanical properties is primarily determined by the on-axis FVF. However, the presence of fiber undulation can further weaken the mechanical properties. Moreover, for AWC-warp specimens, fiber undulation has a significant impact on the modes and characteristics of damage, resulting in fiber breakages and kinks that primarily occur in the connection region of warp yarns.