OPTIMUM BOLTED JOINTS FOR HYBRID COMPOSITE-MATERIALS

The optimum bolted joints for hybrid composite materials composed of g lass-epoxy and carbon-epoxy under tensile loading were investigated. T he design parameters considered for the bolted joints were ply angle, stacking sequence, the ratio of glass-epoxy to carbon-epoxy, the outer diameters of washers and the clamping pressure. As bearing failure wa s desirable for bolted joints, the geometry of the bolted joint specim en was designed to undergo bearing failure only.By inspecting the frac ture surfaces of the specimens it was found that delamination on the l oaded periphery of the holes and extensive damage on the edge region c onstrained by a washer occurred. To assess the delamination of the hyb rid composite materials, three-dimensional stress analysis of the bolt ed joint was performed using a commercial finite-element software and compared with the experimental results. (C) 1997 Elsevier Science Ltd.