Structural behaviour of a deployable Tensairity beam: influence of cables and hinges MEMBRANES 2011

A Tensairity structure has most of the properties of a simple air-inflated beam, but can bear to hundred times more load [1]. This makes Tensairity structures very suitable for temporary and mobile applications where lightweight solutions that can be compacted to a small volume are a requirement. However, the standard Tensairity structure cannot be compacted without being disassembled. By replacing the standard compression and tension element with a mechanism, a deployable Tensairity structure is achieved that needs - besides changing the internal pressure of the air beam - no additional handlings to compact or erect the structure [2]. The deployable Tensairity beam contains - unlike the standard Tensairity structure – hinges (in its struts) and cables (connecting these hinges). The influence of these elements on the structural behaviour of the deployable beam is investigated in this research and compared with the behaviour of the standard Tensairity structure. This is done by means of numerical and experimental investigations on a five meter deployable spindle shaped Tensairity beam. The paper presents first briefly the numerical model of the structure and the experimentally tested five meter prototype. The detailing and manufacturing is described, as well how the experiments are conducted. The general behaviour of the deployable Tensairity beam, such as its stiffness and maximal load, is discussed. Then, various configurations are studied to analyze the influence on the structural behaviour of the cables and hinges. The numerical and experimental investigations show that a deployable Tensairity beam is achieved with similar structural behaviour as the standard Tensairity beam. Cables connecting upper and lower strut increase the structure’s stiffness, while applying hinges on the other hand decreases this stiffness. Additionally, the results show the necessity of connecting all hinges with a cable if one wants to achieve a decent structural behaviour. Finally, the paper discusses the influence of the cable configuration on the structure’s behaviour under different loading conditions. REFERENCES