The transient response of a coating–substrate structure with a crack in the functionally graded interfacial layer

The transient response of a coating–substrate structure with a cracked functionally graded interfacial layer subjected to an impact load is studied. The crack is located perpendicularly to the free surface of the coating. By using integral transform techniques, the present problem is reduced to a singular integral equation. The dynamic stress intensity factors (DSIFs) are obtained by using the Laplace inversion technique. The influences of the material nonhomogeneity constant and the geometry parameters on the DSIFs are investigated. The obtained conclusions can be used to direct the designment and optimization of the coating–substrate structures.