IMPROVEMENT OF THE USEFULNESS OF PYROLYTIC GRAPHITE IN ROCKET MOTOR APPLICATIONS
Quarterly progress rept. 1 Jun-31 Aug 1961
ATLANTIC RESEARCH CORP ALEXANDRIA VA
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The effect of the gas dynamics on the uniformity of the pyrolytic graphite deposit was noted. A derivation was completed for the exact stressstrain relations for a material which exhibits the form of elastic and thermal anisotropy found in pyrolytic graphite. The over-all problem of stress- strain in a cylinder of finite length was then set up. The problem was separated into two parts, one dealing with the central portion of the cylinder and other dealing with the end effects. A pyrolytic graphite test piece having a coarse-grained microstructure was successfully tested in a 60-sec firing with Arcite 373 5600 F propellant. A segmented nozzle was used in which the test piece was a concentric ring in the throat. The segmented test nozzle was then redesigned to use a larger, contoured section of pyrolytic graphite at the throat. Redesign was necessary for hotter firings 6500 F since no other grade of graphite is serviceable near the throat section under such demanding conditions.