Mechanics of adhesive joints

Summary

In order to understand precisely the nature of adhesive strength, we must at least have exact knowledge of the stress distribution in the adhesive layer arising from residual strain as well as from loading.

In this paper we deal with the thermal stress as a representative residual stress, which occurs during glueing operations. Reducing the problem of the thermal stress to one of boundary traction, the stress function of a rectangular plate whose two parallel opposite edges have been glued to two rigid planes respectively is solved.

The results obtained are found to be in good agreement with those of photoelastic experiments even in the case of a thin plate whose relative dimension is comparable to that of actual adhesive joints. In general the stress distribution changes sharply in the vicinity of the peripheral edge of the cemented plane where some stress concentration occurs. Such a disorderliness of stress distribution, however, diminishes within a short distance from the free edge, and beyond this region the stress distribution in the adhesive layer becomes uniform just as in the case of uniaxial tension.