The effect of laminate orientations on friction and wear mechanisms of glass reinforced polyester composite

Friction and wear properties of polyester composite reinforced with laminated glass fibres are experimentally examined in three different orientations, namely, cross-laminar CL, and inter-laminar (normal, NL and parallel, PL). The rubbing experiments of the composite specimens are carded out against abrasive paper (silicon carbide, P600) under various sliding speed and loading conditions. Experimental results show that PL orientation gives the highest value of friction coefficients followed by NL and CL. Microscopic investigations of the worn surfaces are conducted to identify the operating wear mechanism. They reveal that the weaving configuration in CL orientation inhibits an easy detachment of fibres during the wear process. Therefore, intermediate values of wear resistance between PL and NL orientation are obtained. Furthermore, entrapped soft components of matrix resin between laminates in CL orientation play an important role in reducing the friction coefficient. In NL orientation, the individual fibres within the laminates do not get mutual support as in PL orientation. As a result, fibres suffer bending at their ends, leading to an easy shear mechanism.