Two coplanar cracks in a functionally graded piezoelectric material strip under mechanical and transient thermal loadings

In this paper, the fracture problem of a functionally graded piezoelectric material strip (FGPM strip) containing two coplanar cracks perpendicular to its boundaries is considered. The problem is solved for an FGPM strip that is suddenly heated from the bottom surface under static mechanical loading. The top surface is maintained at the initial temperature. The crack faces are supposed to be completely insulated. Material properties are assumed to be exponentially dependent on the distance from the bottom surface. By using the Laplace and Fourier transforms, the thermoelectromechanical fracture problem is reduced to a set of singular integral equations, which are solved numerically. The stress intensity factors for the cases of the two embedded cracks, two edge cracks, and an embedded crack and an edge crack are computed and presented as a function of the normalized time, the nonhomogeneous and geometric parameters.