Engineering topics

Nowitzky, A. M.

Publications and source records attributed to Nowitzky, A. M..

3 records

NASA NTRS1991

Open-Section Composite Structural Elements

Report describes investigation of manufacture and mechanical properties of graphite-fiber/aluminum-matrix open-section structural elements; e.g., channels and angle bars. Conducted with view toward using such elements to build lightweight, thermally stable truss structures in outer space. Other applications transport to, and assembly at, remote or otherwise uninviting locations. Advantages include shapes permitting high packing density during shipment, convenient paths for routing tubes, hoses, and cables; accessibility of both inner and outer surfaces for repair; and ease of attachment of additional hardware. Easier and require less equipment to fabricate, and more amenable to automated fabrication and assembly at remote site. Disadvantages, not as resistant to some kinds of deformation under load.

Loftin, T. A.↗

NASA NTRS1989

Thermally Stable Truss

Lightweight truss made of materials that yield low thermal expansion and contraction. Average coefficient of thermal expansion minus 0.0428 part per million per degree Fahrenheit (0.0770 ppm/degree C) between minus 100 and plus 150 degree F (minus 73 and plus 66 degree C). Rotational distortion of truss less than 1/4 degree as temperature is varied through same range. High thermal conductivity minimizes temperature gradients, minimizing thermal distortions under variety of heating and cooling conditions. Elements of truss readily assembled.

Nowitzky, A. M.↗

NASA NTRS1988

Space structures concepts and materials

An extension is preseted of the evaluation of graphite/aluminum metal matrix composites (MMC) for space structures application. A tubular DWG graphite/aluminum truss assembly was fabricated having the structural integrity and thermal stability needed for space application. DWG is a proprietary thin ply continuous graphite reinforced aluminum composite. The truss end fittings were constructed using the discontinuous ceramic particulate reinforced MMC DWAl 20 (trademark). Thermal stability was incorporated in the truss by utilizing high stiffness, negative coefficient of thermal expansion (CTE) P100 graphite fibers in a 6061 aluminum matrix, crossplied to provide minimized CTE in the assembled truss. Tube CTE was designed to be slightly negative to offset the effects of the end fitting and sleeve, CTE values of which are approx. 1/2 that of aluminum. In the design of the truss configuration, the CTE contribution of each component was evaluated to establish the component dimension and layup configuration required to provide a net zero CTE in the subassemblies which would then translate to a zero CTE for the entire truss bay produced.

Nowitzky, A. M.↗