Recently, fiber reinforced plastics (FRP) are being widely used as the elements of sandwich constructions. Such sandwich constructions are superior in improving flexural rigidity as well as making laminated structures. However, few fundamental studies have been carried out on the sandwich constructions composed of plastic materials, and their mechanical and functional properties remain unclear.
The present paper examines the mechanical properties of an unsymmetrically laminated sandwich construction which is composed of the polyurethane form (PUF) as the core material and aluminium (Al) and glass mat FRP (GRP) as the facing materials so as to enhance hybrid effectiveness. Particularly, the basic problems associated with flexural properties of the sandwich construction GRP/PUF/Al, such as the behaviors of flexural fracture, and the test methods of laminated construction are examined. Two types of flexural tests are carried out by using three and four point loading systems and the results are treated theoretically as well as experimentally to clarify the characteristics of the sandwich construction in which the core material has comparatively lower elastic modulus than the facing materials.
