A Unified Definition of Stress Intensity Factors for Cracks/Corners/Interface Cracks/Interface Corners in Anisotropic/Piezoelectric/Viscoelastic Materials

To have a definition covering all the possible situations of singular orders (real or complex, distinct or repeated), the matrix form near tip solutions of interface corners written by the Stroh's complex variable formalism of anisotropic elasticity were employed in this paper. Starting from the matrix form near tip solutions for anisotropic elastic materials, identical mathematical expressions were applied to the cases of piezoelectric materials and viscoelastic materials by the ways such as the expansion of the elastic properties to include the piezoelectric effects, and the use of the Laplace transform to make the viscoelastic stress-strain relations look like linear elastic materials. The stress intensity factors defined through the matrix form expression are therefore unified for several different situations. With this unified definition, some special cases are reduced and compared with the definitions proposed in the literature.