Static and ultimate state analysis of CFRP double-layer grids

As increased in span, the selfweight and internal force of space structures in large span are also much increased, thus span of space structures is limited. Indeed, the lower weight of composite structures compared to conventional metallic structures achieves directly the weight reduction goal. Therefore, composites provide an alternative to replace conventional materials. In this paper, double-layer grids, one of the most popular space structures, are investigated. Firstly, the mechanical behaviors of CFRP tubes were studied. The design procedure of FW CFRP tubes subjected to axial loading in CFRP double-layer grids was proposed. And then, compressive and tensile strengths of series of CFRP tubes with variety of winding angles were presented. The results indicated that 0/90 lay-ups for CFRP tubes may be the best candidate. Secondly, based on identical deformation principle, CFRP double-layer grids, in which steel tubes were replaced by CFRP tubes, were designed. Thirdly, static and ultimate state analysis of CFRP double-layer grids and the same types of steel double-layer grids was carried out using the finite element program ABAQUS. The analytic results indicated that ultimate load-carrying capacity of CFRP double-layer grids is obviously higher than that of steel double-layer grids. It is seen from load-displacement curves that CFRP double-layer grids behave more brittle.