Non-linear modeling of tubular adhesive scarf joints loaded in tension

In this paper, a simple analytical model is developed to determine the adhe sive shear strain distribution of a tubular adhesive scarf joint loaded in tension. The approach is an extension of the original well-recognized Volke rsen's shear lag analysis for a shear loaded joint, which is frequently app lied to adhesively-bonded joints. A mathematical representation consisting of linear and exponential functions is employed to model the elastic-plasti c behavior commonly observed in structural adhesives. The governing equatio n is found to be in the form of a non-linear second-degree ordinary differe ntial equation with variable coefficients. A numerical method required for solving this equation is also introduced. Numerical predictions of shear st rain distributions are compared with results from non-linear Finite Element Analysis (FEA), utilizing the commercially available software, ANSYS 5.6, a general-purpose software system. It is shown that both the linear and non -linear approximate solutions are closely comparable with the FEA results f or a 10 degrees -scarf angle and elastic isotropic adherends. In concurrenc e with previous work on flat adherends, the present work demonstrates that the scarf joint develops more uniform shear stress and strain distributions with a consequent reduction in peak values than those for the conventional lap joint. In contrast, the conventional lap joint with the equivalent bon ded surface area experiences a more substantial elastic trough, which can p rovide a more stable configuration for, sustained long term loading applica tions.