Stress analysis of single-lap bonded joints in composite tubes under torsion and hygrothermal effects using DQM

In this research, adhesively tubular single lap joints subjected to torsional and hygrothermal loadings are studied using the Differential Quadrature Method (DQM), in which the lateral deflections are taken into account. The analysis is based on the linear cylindrical shell theory. At first, governing differential equations of the tubes and the interfacing adhesive layer are expressed in terms of the displacement field components. The total structure is divided into the overlapping and non-overlapping areas. The differential equations of the overlapping area which do not have closed form solution, are discretized by implementing the DQM. Then, the equations of the total areas are solved simultaneously regarding their boundary and continuity equations, to find the circumferential and radial (lateral) displacements. Next, having known the displacement field components, the distribution of the peel and shear stresses in the interfacing adhesive are calculated. Results obtained from the presented DQM solutions are compared well with those of a published reference as well as those of an ABAQUS finite element model. Finally, using the DQM model, the influence of the adhesive layer thickness, the overlap length, and the changes in the temperature and relative humidity on the interfacing stress distributions are investigated.