In the design of long-life, spaceborne dewars the supports must be considered not only as a structural member, but also as part of the thermal isolation of the cold assembly. Filament-wound composite tension straps provide the strength needed for the launch environment while minimizing heat conduction into the dewar. The optimum material for this application has a large ratio of fatigue strength to thermal conductivity to minimize heat input and a high modulus of elasticity to maximize the system resonant frequency. The material that exhibits the best combination of these properties and has been used in numerous spaceborne dewars is fiberglass/epoxy. This paper presents measurements of mechanical and thermal properties of straps made of a newly-developed alumina fiber with epoxy resin. This composite has significantly higher fatigue strength and modulus of elasticity than fiberglass/epoxy and similar thermal conductivity. This material therefore appears to be the best available choice in the future for dewar tension strap supports. Heat input through the tension straps is also minimized by proper orientation within the dewar. Predictions of dewar thermal performance using alumina/epoxy straps and the improvement compared to a system using fiberglass/epoxy are presented for several relevant dewar applications. This new composite will likely become the material of choice for many future applications requiring structural support with maximum thermal isolation.
Next-generation tension strap supports for spaceborne dewars
Zugbandaufhaengungen der naechsten Generation fuer Dewargefaesse in der Raumfahrt
AIAA-Papers ; Jun ; 1-8
1987
8 Seiten, 9 Bilder, 2 Tabellen, 9 Quellen
Aufsatz (Konferenz)
Englisch