Assistant manager, Materials Engineering, TRW Systems, Redondo Beach, Calif.
Pages: 10 Published: Jan 1975
Composite sandwich structures, composed of graphite-epoxy face sheets on aluminum honeycomb core, were found to successfully withstand 15 000 thermal cycles between -250 and 150°F (-157 and 66°C) in vacuum. Although thermal cycling induced microcracking in the face sheets, laminate flexural and tensile properties were unaffected, and the only noticeable effect was on the coefficient of thermal expansion and flatwise tensile strength of the sandwich. In addition, exposure of the structure to 95 percent relative humidity resulted in a finite change in dimensions, but no effect on the coefficient of thermal expansion.
These environmental effects were determined on composite sandwich structures selected for isotropy, uniformity of mechanical properties at temperature extremes, and balanced thermal expansion characteristics in two perpendicular directions.
composite materials, sandwich structures, thermal expansion, thermal cycling tests, vacuum, moisture, mechanical properties, microstructures
Paper ID: STP32314S