An analytical model to determine the stress singularity and critical bonding angle for an elastic-viscoelastic bonded joint

Measurements of interface bonding strengths are necessary for predicting the failure behavior of structures and materials with bi-material interfaces. However, it is well known that due to the discontinuity of material properties, stress singularity may exist at the edges of the interface. For accurate determination of the bonding strength of bi-material interface, the elimination of the stress singularity is necessary. This paper presents an analytical solution for the determination of the stress singularity and the critical bonding angle of a bonded joint between elastic and viscoelastic materials. This solution is based on the analytical solution available for an elastic-elastic bonded joint via the elastic-viscoelastic corresponding principle. For the viscoelastic material, both time-independent and time-dependent Poisson's ratios are considered to find its effect on the stress singularity. As an example, the developed solution is applied to a simulated aluminum-epoxy bonded joint with a spherical interface. It is found that the critical bonding angle and the order of the stress singularity are different for assuming a time-independent or time-dependent Poisson's ratio of the idealized viscoelastic epoxy.With the analytical solution developed, it is possible to design an optimal interface geometry that can eliminate the stress singularity from the interface corner. © Springer Science+Business Media, B. V. 2011.