Damage assessment of sandwich structures with Al/SiC functionally graded plasma sprayed faceplates subjected to single and repeated impacts

Structural response, energy absorption, and damage mechanisms of honeycomb sandwich structures (HSS) subjected to single and repeated impacts were investigated in present work. The HSS was constructed with an Al/ SiC functionally graded plasma sprayed (FGPS) face plate and aluminium honeycomb core. Experiments were carried out using single-stage gas gun to study the effect of repeated impacts at a constant impact energy of 260 J. A numerical model based on the piecewise plasticity and Johnson-Cook material models was developed to study the effects of impact energy ranging from 164 J to 754 J. The experimental and numerical results were correlated for the case of 260 J impact, and they show good agreement with regard to dent width, central deflection, core compression, and damage area. The energy absorption of the top faceplate rises as the impact energy increases owing to the local indentation, whereas the energy absorption of the core decreases. Two failure modes were observed in the FGPS coating, namely tensile delamination and shear delamination. The accumulation of damage in the coating of FGPS plate and FGPS HSS were mapped through image processing. Thus the current research provides a detailed understanding of the damage behaviour of HSS under various impact scenarios.