Rail shear testing of composite materials: analysis and experiment

This report discusses the results of both an experimental test program and a finite element analysis of selected graphite/polyimide rail-shear test specimens. The two-dimensional finite element analysis includes both mechanical and thermal loading (differential expansion) of the specimens and their elastic rails. Parameters in this analysis of unidirectional and symmetric angle-ply laminates include ply layup angles, specimen length-to-width ratio, the effect of flexible rails and the method of load introduction to the specimen. Results of the analysis include shear and normal stress distributions. Two types of tensile rail shear fixtures were investigated experimentally: a uniform thickness, bolted rail shear fixture, loaded diagonally across the specimen test section; and a tapered-thickness, bonded rail shear fixture, loaded axially along the centerline of the specimen test section. Test results include room temperature and 600°F (315°C) strain data taken from various points on the specimen test section during loading.