ABSTRACT
The use of sandwich structures is rapidly growing to construct cost effective, low weight and high performance structures. New materials typically bring new challenges to designers utilize these new materials. Conventional sandwich structures consist of a metallic skin sheets and polyurethane foam core material as an insulating layer. These conventional structures have been used very widely for structural components. However, the durability of those panels become degraded due to delamination at the bonding interfaces, corrosion of the face sheets and stiffness degradation through aging of the foam core over time (Zenkert 1997). This paper introduces an innovative use of glass fiber reinforced polymer (GFRP) sandwich panels as an alternative and solution to these problems. The 3-D FRP sandwich panels presented in this paper consist of two GFRP laminates separated by a foam core where top and bottom GFRP layers are connected together with through thickness fibers as shown in Figure 1. The use of light-weight foam core serves to place the stiffer GFRP face sheets further from the neutral axis and therefore increasing the flexural stiffness and strength. The through thickness fibers increase the shear stiffness of the panel and delay the delamination between the plies of a composite laminate. The panels are fabricated using pultrusion and the through thickness fibers are injected during the pultrusion process.
