Experimental Characterization of An E-Glass/Epoxy Composite Plate in Pin-Loaded Joints

Abstract

Because of increased use of composites, understanding the failure behaviour of composites is important for effective structural designs. In this study, an experimental investigation was carried out to study the behaviour of pin connected E-GLASS/EPOXY composite joints under static loading conditions. Several specimens were fabricated by varying width and hole-to-edge distance and tested in pin bearing. Details of the test-setup were given and the joint configurations were used in a series of 75 such tests on single bolt joints. The results of this study were presented as experimental characterization. The effects of geometric parameters such as ratio between end distance-hole diameter (E/D) and width ratio (W/D) were evaluated. Three failure modes were observed, net-tension, bearing and shear-out failure at the bolt, depending on the geometry adopted. Under single bolt-bearing conditions, the load-displacement curve labelled for E-GLASS/EPOXY composite with [0/90/45/-45/-45/45/90/0] stacking sequence. In addition, bearing strength, shearing and net-tension stress at failure data were presented as functions of the geometric ratios. The results provided useful information for the structural design with this material against joint failures. From the experimental results obtained, it was concluded that the edge distance ratio (E/D) of the specimen strongly affected the bearing strength of composites. In addition, width ratio (W/D) remarkably affected the failure mode. Bearing failure occurred if (E/D) and (W/D) were large enough. Bearing failure mode was thought as the desirable mode since it generally gave a higher strength and failure was less brittle. Net-tension and shear-out failure modes were catastrophic and not progressive. Therefore, the geometry of the composite plate in pin-loaded joints was designed to undergo bearing failure only.