Influence of Negative Poisson’s Ratio on Fracture Morphologies in CFRP Laminates

The Poisson's ratio and Young's modulus of CFRP laminates can be varied by changing their stacking sequences. CFRP with the specific stacking sequence can theoretically perform the “negative” Poisson’s ratio, which causes extension in the direction perpendicular to the loading direction, for example. However, the relationship between Poisson's ratio and fracture morphology has not yet been elucidated. In this study, tensile tests were performed for CFRP laminates with negative, zero and positive Poisson’s ratios, and failure morphologies were experimentally investigated.