The Effect Of Functionally Graded Core OnThe Dynamic Fracture Behavior InModel Sandwich Structures

Fracture behavior under impact loading conditions of functionally graded core in a sandwich construction is examined. A model sandwich structure comprising of a graded core with a bilinear volume fraction variation is considered for numerical simulations. For comparative purposes, conventional sandwiches with a uniform volume fraction core are also developed. The crack tip in both configurations is positioned such that both global and local material characteristics are matched in these two models. The numerical simulations suggest that crack tip loading rates in terms of normal and shear stresses and stress intensity factors are consistently higher in the conventional structure when compared to the graded one. A parametric study of different elastic impedance gradients in the core material suggests enhanced mixed-mode fracture performance of a graded sandwich structure, having a face-sheet/core interface crack when compared to a conventional counterpart under stress-wave loading conditions.