Investigation of Fracture in Transparent Glass Fiber Reinforced Polymer Composites Using Photoelasticity

Abstract

Fiber-reinforced plastic composite materials are being widely used in a variety of load bearing and high-performance structures. Reliable use and optimum design requires accurate methods for predicting their fracture behavior, among other things. Fiber reinforced plastic composites are generally opaque and hence experimental fracture mechanics studies utilize surface measurements or post-fracture analysis. Hence quality transparent glass cloth reinforced polyester composites have been fabricated and transmission photoelasticity used to investigate quasi-static Mode-I fracture. The isochromatic fringe patterns obtained were analyzed using orthotropic photoelasticity to determine Mode-I stress intensity factors. Opening mode stress field equations in conjunction with an orthotropic stress-optic law were utilized to regenerate the isochromatic fringe patterns. Good agreement was found between the regenerated fringe patterns and the experimentally obtained patterns