Steady-state thermal and geometrical non-linear stress analysis of an adhesively bonded tee joint with double support

Abstract

The adhesive joints consist of adhesive layer and adherends with different mechanical and thermal properties. In case the adhesive joint is subjected to a temperature difference, thermal stresses arise in the adhesive joint due to the thermal and mechanical mismatches of the adhesive layer and the adherends. If the thermal expansion of the adhesive joint is restrained the stresses in the adhesive and adherends can reach considerable levels. In this study, the geometrically non-linear thermal stress analysis of an adhesively bonded tee joint with double support was carried out using the finite element method. The configurations of the adhesive tee joint bonded to a rigid base and to a flexible horizontal plate were considered. It was assumed that the adhesive tee joint is subjected to variable thermal boundary conditions, that is, air flows with different temperature and velocity parallel and perpendicular to outer surfaces of the tee joint. In order to determine the thermal strains with respect to a reference temperature, it is necessary to know the final temperature distributions through the adhesive tee joint. The heat transfer analysis of the tee joint showed that high heat fluxes occurred inside the adhesive fillets at the adhesive free ends whereas the vertical and horizontal plates experience uniform low-temperature distributions. Based on the final temperature distribution of the adhesive tee joint its geometrical non-linear stress analysis was carried out considering large displacement effects for two plate edge conditions in which the edges of the vertical and horizontal plates were fully or partly constrained. The stress analyses showed that high stress concentrations occurred inside the adhesive fillets around the adhesive free ends. The surfaces of the vertical and horizontal plates near the free ends of the adhesive–plate interfaces and the adhesive–support interfaces also experience stress concentrations. The adhesive tee joint was subjected to the highest stresses in the adhesive layer and plates when the edges of the horizontal and vertical plates were fully fixed. In addition, increasing the effect of the support length resulted in increases in the peak stresses at the critical locations of the adhesive layer and the plates.