Meso-scale laminate adhesive joints for pultrusions

The study aims to understand the failure of adhesive joints within glass fibre reinforced plastic (GFRP) pultrusions and the effects of moulding materials on adhesion. This is based on experimental and numerical approaches with respect to moulding and adhesive bonding and modelling of relatively small-scale laminates—referred to as “meso”. The small laminates, of dimensions 10 mm×10 mm×1.2 mm, were moulded with various fabric architecture, for the surface layers. These were then sandwiched within metallic adherends by adhesive bonding and tested in shear and tension to study their adhesion. A 2-D closed-form stress analysis was used to model the bonded laminates. The analysis of the meso-scale models showed a good correlation with results from a macro-scale lap-shear model, in relation to transverse stresses in the composite. The study demonstrated the effectiveness of the meso-scale moulding technique and showed a significant adhesion improvement from using a 0/90° inlaid fabric in combination with a random mate, as the surface fabric layer.