Comparative and parametric study of aluminium honeycomb sandwich composites and GRP

Sandwich composites are a special class of material because of distinctive properties such as lightweight, high damping and high energy absorbing capacity, which in turn make this material highly suitable for the shipbuilding industry. The traditionally used materials for hull construction in the shipbuilding industry are steel, Glass Reinforced Plastic (GRP) and wood which is prone to problems such as weight and strength reduction due to water absorption over a period of time. This manuscript presents a comparative study of specific energy absorption (SEA) of GRP sheets and two different aluminium honeycomb sandwich composites one of which has aluminium honeycomb core and aluminium face sheet/skin and the other has aluminium honeycomb core and GRP face sheet. Experiments are carried out on the GRP sheet and sandwich composite with aluminium honeycomb core and aluminium as face sheet using Charpy ASTM E-23 machine. The experimental results are compared with the numerical results obtained from Abaqus and are found to be in good agreement. Further, the numerical simulation has been carried out on sandwich composites and GRP sheets varying several parameters such as foil thickness of honeycomb in sandwich composites, and skin of sandwich composites (aluminium sheet and GRP). Failures have been discussed based on stress theories and the deformation patterns of sandwich composites and GRP sheets (obtained from the numerical and experimental investigation) have been compared. The maximum impulse force has also been presented by using the impulse-momentum equation. It has been found in the study that the aluminium honeycomb sandwich composites with aluminium as face sheet possess high energy absorption to mass ratio than the pure GRP sheets and the aluminium honeycomb sandwich composites with GRP sheet as skin. Further parametric study reveals that the energy absorption to mass ratio increases with increase in foil thickness in both type of honeycomb sandwich composites.