Numerical analysis on the effect of shear keys pitch on the shear performance of foamed sandwich panels

The main problem associated with using composite sandwich panels with foam core is their ability to withstand shear load. The aim of the present work is to extend the knowledge of mechanical properties both on constituent components and on the whole sandwich structures, focusing on the effects induced by inserting semi-circular shear keys between the skin and the foam core. The sandwich panel under investigation is composed of glass fibre reinforced polymer (GFRP) skin with polyvinylchloride (PVC) and polyurethane (PU) foam core, while the shear keys are made of chopped strand (CS) glass fibre impregnated with epoxy resin. The material properties of the skin, keys and foam core materials were investigated through a series of quasi-static tests. The mechanical properties of each component were used as input data in order to implement the finite element (FE) analysis using ABAQUS software. Parametric investigation using the FE analysis to select the most suitable pitch (space between shear keys along the panel) of the shear keys taking into consideration the materials and geometrical nonlinearities as well as the complex interaction between all the mating surfaces was performed. Five different pitches have been investigated namely 15, 25, 35, 45 and 55 mm. The results showed that the model with 45 mm pitch represents the most sustainable model among the others. The FE results were verified with the measured ones extracted from the out-of-plane shear test.