Free-Edge Stress Singularity of Bonded Dissimilar Materials with an Interlayer under Thermal Stress Loading

Abstract

Free-edge stress singularity usually develops near the edge of interface of bonded dissimilar materials. Because of the difference of the coefficient of the thermal expansion of the materials, the residual stress may develop when two materials are bonded. To defuse the residual stress, an interlayer may be inserted between the two materials. Stress distribution near the edge of the interface in the presence of the interlayer is very important to evaluate the strength of the bonded dissimilar materials. In this study, stress distribution on the interfaces of the bonded dissimilar materials with an interlayer under thermal stress loading was calculated by using the boundary element method. An effect of an interlayer on the stress distributions on the interface was examined numerically. It was found that the influence of the interlayer on the stress distribution was limited within a region where distance from interface edge is smaller than the interlayer thickness. Stress distribution around the edge of the interface of the bonded dissimilar materials with an interlayer can be normalized by the parameters of the singularity and the thermoelastic constant stress term of the bonded dissimilar materials without an interlayer.

Identification analysis of order of singularity near vertex on interface in three-dimensional bonded structures

“…From Fig. 7, it is found that the order of the singularity can be correctly identified, even if the initial value of the order of the singularity λ (1) is greater than the target value.…”

“…The computational flow of the identification analysis of the order of singularity is shown below. (1) The initial order of the singularity {λ} (1) and convergence criterion ϵ are input.…”

“…In recent years, considerable researches have been carried out to clarify the stress singularity near the interface edge of bonded structures, e.g., researches on stress singularity under thermal stress loading [1] and comparison of the intensity of the stress singularity between bonded plates and tubes [2]. These studies have centered on the influence of the material properties and the shape of the bonded edge for bonded strength by the order of singularity and the intensity of stress singularity.…”

“…On the other hand, the intensity of stress singularity is obtained by stress analysis using volume force distributed on a fictitious boundary in the region of the stress singularity. This method has been applied to a V-notched model [1], material with an inclusion model [3], and an interface crack model [4]. With this method, it is also necessary to obtain the order of singularity before calculating the intensity of the stress singularity.…”