Influence of elastic gradient profiles on dynamically loaded functionally graded materials: cracks along the gradient

The effect of different elastic gradient profiles on the fracture behavior of dynamically loaded functionally graded materials (FGM) having cracks par allel to the elastic gradient is studied numerically. Finite element analys es of FGM and homogeneous beams are used to examine crack tip responses to low velocity, symmetric impact loading on the uncracked edge of the beams. Elastic description of FGMs consist of unidirectional power-law variation o f E/rho and constant Poisson's ratio. The results show the effect of the va riations in elastic profiles to be relatively small for cases with cracks r esiding on the stiff side of the FGM whereas significant differences are se en when cracks are on the compliant side. Elastic property variations also affect crack tip loading rate and hence crack initiation in FGMs. Crack ini tiation in FGMs with cracks on the stiff side are significantly delayed due to a lower rate of crack tip loading when compared to the opposite configu ration or the equivalent homogeneous materials. (C) 2001 Elsevier Science L td. All rights reserved.