Compression after impact behavior of composite foam-core sandwich panels

Abstract Low-velocity impact tests and compression after impact (CAI) experiments were conducted on composite foam-core sandwich (FCS) panels. The impact tests revealed that the damage depth of the FCS panels increases with an increase in the impact energy. The CAI experiments revealed that the residual compressive strength of the FCS panels decreased with an increase in the impact energy. The local buckling of the FCS panels without impact damage occurred during compression, which was observed by the strain bifurcation phenomena using electrical strain gauge measurements. However, the large strain gradient and compression failure of the FCS panels with impact damage occurred during compression, as observed by the full-field deformation using three-dimensional digital image correlation (3D-DIC) measurements. The numerical simulations using the finite element method (FEM) were consistent with the observed failure phenomena, i.e., the damage at the impact site weakening the compressive strength of the FCS panels.