Abstract
The indentation of unidirectional glass fiber reinforced plastic materials by half-wedge indenters was accomplished. The whitening patterns being produced by indenting are classified into two categories which these are fractured part perfectly and the failure part involving some defects for glass yarns in view of fracture behavior. The distribution of failure pattern (whitening pattern) defined are observed on various relative angle between the wedge face and the direction of yarn in composites and those are compared with that of full wedge indenter mentioned in previous paper. The main results obtained are as follows : (1) The failure pattern by half-wedge indenter dose not show the peculiar behavior presented in the case of full wedge indenter. (2) According as the wedge angle increase, the fracture part spreads in the vertical direction of wedge face in the case of full wedge indenter, while spreads under the indenter in the case of half-wedge indenter. (3) The fracture of yarn occurs in a combination of horizontal stress acting in the direction of fiber and bending moment, whereas failure of yarn occurs with stress acting vertically to the yarn orientation.
