Abstract
In this study, the effect of random fiber waviness on damage and fracture properties of a natural fiber sliver-reinforced composite laminate was discussed through three-dimensional finite element analysis (3D-FEA) and Tsai-Hill criterion. 3D-FEA was carried out by assigning a measured fiber-orientation-angle to each finite element and using the orthotropic theory. In order to predict risky areas causing damage in the composite laminate, Tsai-Hill criterion was first applied for the resultant stress distribution. Next, assuming that an applied stress is isolatedly given to each element, Tsai-Hill criterion was applied without using 3D-FEA. To differentiate such two kinds of evaluations, the subtraction of the latter value from the former was taken for each element. In the negative subtraction, risky Tsai-Hill distributions consisted of a cluster of inclined fibers in the composite laminate. In the positive subtraction, on the other hand, risky Tsai-Hill distributions appeared with dispersion and small-scale level. It was estimated from the comparison with the specimens' fracture paths that the laminate's fracture occurred from the cluster of inclined fibers. However, it was also considered that the fracture was not initiated from the cluster, but caused by fibers breakage on the counterpart in the laminate, because of tensile stress enhancement induced by the cluster.
