In-Plane fracture of laminated fiber reinforced composites with varying fracture resistance: experimental observations and numerical crack propagation simulations

摘要

A series of experimental results on the in-plane fracture of a fiberreinforced laminated composite panel is analyzed using the variationalmulti-scale cohesive method (VMCM). The VMCM results demonstrate the influenceof specimen geometry and load distribution on the propagation of large scalebridging cracks in the fiber reinforced panel. Experimentally observedvariation in fracture resistance is substantiated numerically by comparing theexperimental and VMCM load-displacement responses of geometrically scaledsingle edge-notch three point bend (SETB) specimens. The results elucidate thesize dependence of the traction-separation relationship for this class ofmaterials even in moderately large specimens, contrary to the conventionalunderstanding of it being a material property. The existence of a "freebridging zone" (different from the conventional "full bridging zone") isrecognized, and its influence on the evolving fracture resistance is discussed.The numerical simulations and ensuing bridging zone evolution analysisdemonstrates the versatility of VMCM in objectively simulating progressivecrack propagation, compared against conventional numerical schemes liketraditional cohesive zone modeling, which require a priori knowledge of thecrack path.