Effects of geometry and specimen size on out-of-plane tensile strength of aligned CFRP determined by direct tensile method

The out-of-plane tensile strength of CFRP laminate determined by the direct tensile method varies with specimen geometry and size. This effect was first experimentally observed using aligned CFRP. To explain the geometry and size effects from a mechanical point of view, an analytical model combining Weibull statistics, including the concept of effective volume, and a fracture criterion under multi-axial loading was constructed on the basis of stress distributions calculated using the finite element method. The predicted out-of-plane tensile strength of aligned CFRP was found to be consistent with experimental results. Thus, the present model is useful for reducing experimentally determined out-of-plane tensile strength under complex stress distributions to that under a uniaxial and uniform stress distribution.