Experimental, analytical and numerical study of mechanical properties and fracture energy for composite sandwich beams

In this study, the mechanical and fracture behaviour of marine sandwich-structured composite that is manufactured by vacuum-assisted resin infusion process with a PVC foam-web core, and different thicknesses of upper and lower glass fibre-reinforced polymer face sheets used as outer and inner side of the hull have been examined. The properties of PVC core, face sheet material, and composite sandwich structures are presented. Failure modes include sandwich flatwise tension, core flatwise compression, sandwich edgewise compression, and face sheet bending of manufactured composites have been investigated experimentally for marine application. The analytical solution is derived to calculate the flexural rigidity, shear stresses and maximum tensile, compression stresses in three-point bending specimens for marine sandwich composites. 3 End Notched Flexure test method has been applied to calculate the strain energy release rate. Moreover, the finite element study is carried out by using a 2D model to calculate the fracture energy (J) value numerically and virtual crack closure technique. Reasonably good results are obtained between analytical and numerical methods.