Composite component incremental consolidation for fiber waviness inhibition and its effect on damage progression of curved beams

Severe fiber waviness defect often occurs during the consolidation process of fiber reinforced polymer composite component, which arises from that multiple interactional plies start to slide simultaneously and out-of-control under sufficient pressure. In this study, based on the significant in-plane tension gradient along thickness of viscoelastic composite, a concept of incremental consolidation was proposed to actively inhibit fiber waviness in prepreg-based composite component. Via applying a series of tiny step pressures continuously, plies were triggered to slide and consolidate layer by layer from top to bottom with a just-right in-plane tension and concurrent stresses relaxation. Incremental consolidation avoided the complex interaction among plies and allowed in-plane tension to be significantly reduced by 165 times compared with autoclave processing with a constant pressure. The fiber waviness defects in a typical wing spar were successfully inhibited by the proposed method. The failure load of the component increased by 1.5 times and curved beam strength increased by 1.1 times while elastic displacement increased by 75%. The inhibition method was highly effective, easy to implement and affordable, which showed considerable promise to improve the manufacturability of the primary structural composite components.