  In this paper, the flutter behaviour of simply supported square functionally
graded material plates immersed in a supersonic flow is studied. An enriched
4-noded quadrilateral element based on field consistency approach is used for
this study and the crack is modelled independent of the underlying mesh. The
material properties are assumed to be temperature dependent and graded only in
the thickness direction. The effective material properties are estimated using
the rule of mixtures. The formulation is based on the first order shear
deformation theory and the shear correction factors are evaluated employing the
energy equivalence principle. The influence of the crack length, the crack
orientation, the flow angle and the gradient index on the aerodynamic pressure
and the frequency are numerically studied. The results obtained here reveal
that the critical frequency and the critical pressure decreases with increase
in crack length and it is minimum when the crack is aligned to the flow angle.
