1577. Material Selection for Lightweight Dimensionally Stable Space Structures: An Elastic/Plastic Analytical Trade Study

Paper

Abstract

Analytical trade studies were performed to investigate hybrid material systems for use in dimensionally stable, deployable space antennas. To meet overall stiffness and weight requirements, graphite-epoxy was selected as the baseline material for the antenna ribs. The rib laminate was designed to yield maximum stiffness and minimum thermal and viscoelastic distortions. Rib thermal expansion was further minimized by adhering a metallic foil to the outside surface of the rib. Foil materials considered in the study include aluminum, magnesium, titanium, molybdenum, steel, and beryllium-copper. Results of the analysis indicate that titanium, molybdenum, steel, and beryllium-copper foils are effective in adjusting the thermal expansion characteristics of the rib and remain elastic during the operational phase of the antenna. Foil elasticity is required for linear response of the antenna structure. Additional design constraints such as thermal conductivity, weight, and manufacturing considerations favor beryllium-copper surface foil as the leading candidate for this application.