A study of skin-core adhesion in glass fibre reinforced sandwich materials

A test technique for measuring skin-core adhesion in fibre reinforced sandwich structures has been developed and applied. The test enables the interfacial fracture energy to be measured for most standard sandwich constructions. The technique has been subsequently employed to investigate skin-core adhesion in a number of sandwich structures similar to those currently used in the marine industry. It has been shown that the interfacial fracture toughness of a GFRP-crosslinked PVC sandwich structure can be as high as 2700 J/m²; however, sandwich constructions based on balsa cores offered considerably lower values of interfacial fracture energy. Here it was found that pre-treating the balsa core prior to bonding of the composite skins has a deleterious effect on the measured fracture toughness. Finally, the results of these tests have been correlated with data obtained from conventional climbing drum and short beam shear tests.