Structural Efficiency of Composite Struts for Aerospace Applications

The structural efficiency of carbon-epoxy tapered struts is considered through trade studies, detailed analysis, manufacturing and experimentation. Since some of the lunar lander struts are more highly loaded than struts used in applications such as satellites and telescopes, the primary focus of the effort is on these highly loaded struts. Lunar lander requirements include that the strut has to be tapered on both ends, complicating the design and limiting the manufacturing process. Optimal stacking sequences, geometries, and materials are determined and the sensitivity of the strut weight to each parameter is evaluated. The trade study results indicate that the most efficient carbon-epoxy struts are 30 percent lighter than the most efficient aluminum-lithium struts. Structurally efficient, highly loaded struts were fabricated and loaded in tension and compression to determine if they met the design requirements and to verify the accuracy of the analyses. Experimental evaluation of some of these struts demonstrated that they could meet the greatest Altair loading requirements in both tension and compression. These results could be applied to other vehicles requiring struts with high loading and light weight.