Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781723202469 Category : Languages : en Pages : 160
Book Description
Mechanical, thermal, and physical property test data was generated for as-fabricated advanced composite materials at room temperature (RT), -150 and 250 F. The results are documented of mechanical and thermophysical property tests of IM7/PEEK and discontinuous SiC/Al (particulate (p) and whisker (w) reinforced) composites which were tested at three different temperatures to determine the effect of temperature on material properties. The specific material systems tested were IM7/PEEK (0)8, (0, + or - 45, 90)s, (+ or - 30, 04)s, 25 vol. pct. (v/o) SiCp/Al, and 25 v/o SiCw/Al. RT material property results of IM7/PEEK were in good agreement with the predicted values, providing a measure of consolidation integrity attained during fabrication. Results of mechanical property tests indicated that modulus values at each test temperature were identical, whereas the strength (e.g., tensile, compressive, flexural, and shear) values were the same at -150 F, and RT, and gradually decreased as the test temperature was increased to 250 F. Similar trends in the strength values was also observed in discontinuous SiC/Al composites. These results indicate that the effect of temperature was more pronounced on the strength values than modulus values. Rawal, Suraj P. and Misra, Mohan S. Unspecified Center METAL MATRIX COMPOSITES; ROOM TEMPERATURE; SILICON CARBIDES; TEMPERATURE EFFECTS; THERMAL STABILITY; THERMODYNAMIC PROPERTIES; THERMOPHYSICAL PROPERTIES; WHISKER COMPOSITES; COMPRESSIBILITY; CONSOLIDATION; DELAMINATING; DIMENSIONAL STABILITY; FABRICATION; MICROCRACKS; NONDESTRUCTIVE TESTS; PARTICULATES; RESIDUAL STRESS; TECHNOLOGY UTILIZATION; THERMAL CYCLING TESTS...
Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781723544095 Category : Languages : en Pages : 492
Book Description
The objectives of the program were to: generate mechanical, thermal, and physical property test data for as-fabricated advanced materials; design and fabricate an accelerated thermal cycling chamber; and determine the effect of thermal cycling on thermomechanical properties and dimensional stability of composites. In the current program, extensive mechanical and thermophysical property tests of various organic matrix, metal matrix, glass matrix, and carbon-carbon composites were conducted, and a reliable database was constructed for spacecraft material selection. Material property results for the majority of the as-fabricated composites were consistent with the predicted values, providing a measure of consolidation integrity attained during fabrication. To determine the effect of thermal cycling on mechanical properties, microcracking, and thermal expansion behavior, approximately 500 composite specimens were exposed to 10,000 cycles between -150 and +150 F. These specimens were placed in a large (18 cu ft work space) thermal cycling chamber that was specially designed and fabricated to simulate one year low earth orbital (LEO) thermal cycling in 20 days. With this rate of thermal cycling, this is the largest thermal cycling unit in the country. Material property measurements of the thermal cycled organic matrix composite laminate specimens exhibited less than 24 percent decrease in strength, whereas, the remaining materials exhibited less than 8 percent decrease in strength. The thermal expansion response of each of the thermal cycled specimens revealed significant reduction in hysteresis and residual strain, and the average CTE values were close to the predicted values. Rawal, Suraj P. and Misra, Mohan S. and Wendt, Robert G. Unspecified Center NASA-CR-187472, NAS 1.26:187472, MCR-90-502 NAS1-18230; RTOP 506-43-21-04...
Author: National Aeronautics and Space Administration (NASA)
Author: S. P. Rawal
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Author: Suraj P. Rawal
Author: National Aeronautics and Space Administration (NASA)