Experimental and Theoretical Study on Behaviour of Geometrically Asymmetric Composite Marine Sandwich Beams under Bending Load

Abstract

This study presents a detailed investigation on the three-point and four-point bending behaviour of asymmetric sandwich beams composed of polyvinyl chloride (PVC) foam core and E-glass fibre reinforced polymer face sheets. The effects of mid-plane asymmetry on the bending load-displacement behaviour and failure mechanism of the sandwich beams were examined. Simple analytical expressions accounting for flexural and shear rigidities of the sandwich beams were proposed to predict the failure load, mid-span deflection and equivalent bending stiffness of the specimens and validated against experimental results. By shifting the loading direction, the flexural behaviour of asymmetric beams may be controlled. On the loading side, the use of face sheet with thick or high in-plane mechanical characteristics resulted in a delay in compressive failure of the top face sheet. The effective bending stiffness was overestimated since the applied formula did not account for shear deformations. First-order shear deformation theory was used to estimate the mid-span displacement values of sandwich beams in elastic regime and showed good agreement with the experimental results.