Pr. Marur et Hv. Tippur, Numerical analysis of crack-tip fields in functionally graded materials with a crack normal to the elastic gradient, INT J SOL S, 37(38), 2000, pp. 5353-5370
The nature of the singular field around the crack in functionally graded ma
terial (FGM) is analyzed parametrically using finite element method. The nu
merical simulations are carried out by varying the location of the crack in
the graded region for different material gradients. Using linear material
property variation in the gradient zone, the influence of material gradient
and the crack position on the fracture parameters such as complex stress i
ntensity factor (SIF) and energy release rate are studied. The crack openin
g displacement profiles of FGM are compared with the homogeneous and bimate
rial counterparts. The analysis shows that the fracture parameters of FGM a
pproach that of the bimaterial as the material gradient is increased, regar
dless of the position of the crack in the graded region. The extent of appl
icability of the homogenous crack tip fields around the crack in FGM is ana
lyzed, and the results show that the size of the homogeneous field reduces
with the increase in material gradient. Static fracture experiments are con
ducted on epoxy based FGM to determine complex SIF with electrical strain g
ages, using the homogeneous field equations to convert the strains to SIF.
The measured SIF values compare favorably with the numerical results provid
ing a limited experimental validation of the computations and the use of ho
mogeneous field for FGM. (C) 2000 Elsevier Science Ltd. All rights reserved
.