Strain energy release rate of sandwich composite beams for different densities and geometry parameters

In this paper, fracture behaviour of marine sandwich structured composite beams manufactured by vacuum-assisted resin infusion process with a PVC foam core, and different thicknesses of upper and lower glass fibre-reinforced polymer face sheets have been investigated. Fracture toughness in terms of strain energy release rate of sandwich composite beam is obtained using three end notched flexure test (3 ENF) by analytical method, finite element simulation using J integral and virtual crack closure technique (VCCT). Experimental testing has been applied with more accurate loading values for finite element modelling (FEM) simulations. The good agreement between experimental and numerical results shows that the finite element model is acceptable. A parametric study is carried out to observe the effects of core thickness, density of core, length of specimens, loading directions of the specimens on strain energy release rate (SERR) of sandwich composite beams under mode II loading. It is developed for the different core thicknesses with varying density combinations. The variations of maximum SERR value are presented graphically using numerical method and compared with analytical solution