Analysis and enhancement of tubular bonded joints subject to torsion

The increasing trend in the use of Adhesively Bonded Joints (ABJ), which is replacing the use of conventional joints in many industries, makes the determination of their strengths and weaknesses of significant importance. Ease of production, maintenance and a controllable stress distribution are only a few key factors that attest to the superiority of ABJ compared to mechanically fastened joints. There are extensive investigations in literature that detail the behavior of ABJ under different loading conditions; however, only a few of them have addressed torsional loading.;The first section of this thesis is comprised of a comprehensive study on tubular ABJ under torsional loading wherein both isotropic and composite adherends are investigated. Both the finite element method (FEM) and experimental approaches were used in this study. ABAQUS, a widely used commercial finite element code, was used to develop a series of FEM models to examine the linear and non-linear behaviors of ABJ under torsional loading. The FEM results were validated by experimental results obtained through an extensive series of static and cyclic torsional tests conducted on joints made of metallic and composite adherends. Good agreement was observed between the results obtained from the two methods. In addition, the influence of fabrication method on joint performance was examined. The results of this investigation have been collated into a series of design curves and manufacturing recommendations that are verified by various test methods.;In the following section, the possibility of enhancing the response of composite joints by the incorporation of smart materials (i.e. shape memory alloys) was explored. It was concluded that shape memory alloys (SMA) can be used for increasing the strength and stiffness of composite joints that are subject to elevated temperatures at which the composite adherends' mechanical properties would be otherwise degraded. Subsequently, a comprehensive method for the design and fabrication of SMA embedded hybrid composites (SMAHC) was introduced. Furthermore, the behavior of SMAHC, compared to its non-reinforced composite counterpart, was investigated under static and cyclic loading conditions. It was demonstrated that SMA embedment could significantly enhance the performance of a composite compared to its non-reinforced counterpart.