Transient response of an edge interfacial crack in bonded dissimilar strips with a functionally graded interlayer under an antiplane shear impact

The transient response of an edge interfacial crack in bonded media with a functionally graded interlayer is investigated under the condition of an antiplane shear impact. The graded interlayer is assumed to follow power-law variations of the shear modulus and mass density between two dissimilar, homogeneous semi-infinite strips. Based on the use of Laplace and Fourier integral transforms, the crack problem is formulated in terms of a singular integral equation with a generalized Cauchy kernel, which is solved by the expansion-collocation technique in the Laplace domain. The time-dependent crack-tip behavior is determined through an inverse Laplace transform and the values of the mode III stress intensity factors are obtained as a function of time. The numerical results include the variations of such dynamic stress intensity factors for various combinations of the material and geometric parameters of the bonded system; more specifically, the effects of shear modulus, mass density, layer thickness, and their interactions on the dynamic overshoot characteristics of the transient crack-tip behavior in the presence of the graded interlayer are examined.