The Influence of Variations in Glue-Line Thickness on the Load Transfer in Double Overlap Joints

Abstract

Abstract The equilibrium equation of the classical theory of joints is not, in general, soluble in closed form for variable glue-line thickness. It is shown, however, that analytical results describing the influence of thickness variations can be obtained by two methods: a perturbation method and an inverse method. Detailed calculations are given for thickness variations which are most pronounced at one end of the joint and which can be characterized by two parameters, namely an amplitude and a decay length. Of the two methods, the perturbation method is the more flexible in application, but its accuracy relies on the amplitude being sufficiently small, while the inverse method can lead to an exact solution which can be used to assess the range of accuracy of the two-term perturbation expansion. Certain practical implications of the results obtained are discussed.