Abstract
The establishment of large space systems in the Earth's orbit requires the development of new construction techniques. As large structures are being proposed for future projects, several orbit construction processes have evolved. Of these, the concept of deployable truss structures is one which is appraised during this research. An energy loaded joint is presented which realises the potential of this technique. Incorporated into a skeletal truss framework, however, the structural characteristics of the joint will influence the overall performance of the structure. In order to assess the significance of this, an investigation is conducted into the structural behaviour of the joint. Although the deployable concept has been primarily developed for realising large structures in the Earth's orbit, the technique can also be used in terrestrial applications. Accordingly, a numerical study evaluates the static stress distribution generated through the joint; the structure is considered to be in a fully deployed state. The investigation appraises the effects of manufacturing tolerances and indicates their significance on design. Dynamic loading induced in the space environment highlights the joint to possess a strong geometrical nonlinearity. The joint describes a bilinear flexural stiffness property that is associated with the design. As a consequence, resonant frequencies exhibited by small truss structures are found to be dependent on a variety of geometric and loading parameters. Large trusses are also found to be affected although their behaviour is seen to be less dependent on the characteristics of individual joints. An experimental investigation confirms the presence of nonlinearity within the energy loaded joint. The characteristic response during vibration highlighted the difficult task of predicting structural behaviour. This instigated a redevelopment of the joint design incorporating measures which eradicate the cause of the geometrical nonlinearity. Tests reveal this design to be a significant improvement and an important contribution to the development of deployable structures.