Deployable tubular bar structures with laterally confined flattened ends

Abstract

[Abstract] The article proposes a simple and efficient system for connecting the bars and the linkages in deployable structures. These structures must allow precise movements for unfolding and folding, which requires specific linkages that have been the subject of numerous studies. In contrast, the linkage-bar connection has hardly been studied. This article analyses this connection using a system based on crushing the ends of the bars, but introducing a modification that considerably improves its efficiency. It consists of flattening the end of the tube in a press with lateral confinement, which concentrates the entire section of the tube, but which limits the transversal expansion. The response of flattened tubes without accessory elements is studied, as well as other variants of the system by inserting at the ends of the bar either intermediate plates or a section of tube. The different types of bars with flattened ends have been tested to failure and the resistance capacities of the proposed solutions have been analysed. The results obtained demonstrate the structural efficiency of the proposed system, with a clear improvement over unflattened tubes.