Analytical method for determination of temperature-induced interfacial shear stress in foam-core composite sandwich materials

Composite sandwich materials with glass fibre-reinforced plastic (GFRP) skins and a foam core have been widely used in civil engineering. However, the interfacial delamination is the main failure mode in practice, especially at elevated temperatures. Temperature-induced interfacial shear stress can be generated because of the different coefficients of thermal expansion of GFRP skin and foam core, which can weaken the interfacial bond strength of sandwich materials. In this study, to investigate the distribution of temperature-induced interfacial strain, an analytical model was developed by using the infinitesimal method. In the meantime, a series of foam-core composite sandwich materials were tested via a kind of non-direct test method at different temperatures to validate the accuracy of the proposed analytical model. Finally, the comparison between experimental and analytical results demonstrates that the proposed analytical model can predict the interfacial strain distribution of sandwich structures at elevated temperatures.