### STP580: Optimization of the Thermal Shock Resistance of Carbon-Carbon Composites

Guess, TR

*Staff member, Sandia Laboratories, Albuquerque, N. Mex.*

Butler, BL

*Staff member, Sandia Laboratories, Albuquerque, N. Mex.*

Pages: 18 Published: Jan 1975

**Abstract**

A three-dimensional rule of mixtures model was developed to calculate the room-temperature thermal and mechanical properties of carbon-carbon composites whose constituents have anisotropic properties. The model was used, along with the properties of different carbon fibers and pyrocarbon matrices, to determine the fiber-matrix combination, constituent volume fractions, and constituent orientations that maximize expected composite thermal shock resistance of heat shields. The results indicate that a composite having a low volume fraction of high-modulus carbon fibers, arranged in a 3D array, and coated with anisotropic, heat-treated pyrocarbon matrix, will have the maximum thermal shock resistance. Confidence in the model was established by good agreement between model predictions and experimental data on actual carbon-carbon composites.

**Keywords:**

carbon, composite materials, thermal shock, mechanical properties, carbon fibers, pyrocarbon matrix, models, reentry materials

**Paper ID:** STP32311S

**Committee/Subcommittee:** D30.08

**DOI:** 10.1520/STP32311S

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