Mechanical properties and damage behavior of bi-directional glass fiber non-crimp fabric laminates: effects of laminate and nesting configurations

This study investigates the mechanical properties, failure behavior, and damage mechanisms of bi-directional glass fiber non-crimp fabric (NCF) laminates, focusing on the effects of nesting conditions and laminate configurations. The laminates were fabricated using the vacuum-assisted resin transfer molding (VaRTM) process and tested under tensile loading at 0° and 30° orientations. The bi-directional NCF materials consist of 0° fiber bundles in the warp direction and 90° fiber bundles in the weft direction. Four distinct laminate configurations were analyzed to understand the influence of fiber alignment and nesting conditions on mechanical performance. The 30° loading direction was chosen to examine the combined effects of tensile and shear stresses. Results demonstrate that nesting conditions and laminate configurations significantly affect crack initiation, propagation, and failure behavior. Laminates with nesting exhibited delayed crack propagation, more uniform crack distribution, and improved load-bearing capacity. In contrast, non-nested laminates displayed void-induced cracking, rapid crack propagation, and reduced structural integrity. This study provides a comprehensive evaluation of the failure behavior and damage mechanisms in bi-directional glass NCF laminates, offering valuable insights for optimizing composite materials in aerospace, automotive, and other structural applications.