Original Paper(Vol.61 No.12 pp.926-931)

Logarithmic Free-Edge Stress Singularity in Bonded Dissimilar Orthotropic Materials

Seiji IOKA, Tomoyuki ISHIDA and Shiro KUBO

Abstract:When two materials are bonded, free-edge stress singularity usually develops at the intersection of free-surfaces and interface. The order of the free-edge stress singularity p can be obtained as a root of the characteristic equation deduced in terms of Airyfs stress function. It is theoretically predicted that logarithmic free-edge singularity develops when the order of the singularity p has double root, but no numerical examination is available in the literature. In this study, stress distribution on the interface of the bonded dissimilar orthotropic materials is calculated by using the boundary element method (B.E.M.) under the condition where the order of the singularity has the double root of the characteristic equation. It was found that the logarithmic free-edge stress singularity developed under mechanical loading. The order of the stress singularity calculated by the nonlinear least squares method from the stress distribution obtained by B.E.M. analyses agreed well with one obtained by using the characteristic equation. The logarithmic free-edge stress singularity developed under thermal stress loading also.

Key Words:Bonded dissimilar materials, Orthotropic material, Interface, Free-edge stress singularity, Boundary element method