Presenter Information

Robert B. Stone


Mechanical and Aerospace Engineering

Research Advisor

Dharani, Lokeswarappa R.

Advisor's Department

Mechanical and Aerospace Engineering

Funding Source

This work was supported by OURE (UMR Opportunity for the Undergraduate Research Experience Program), NASA Missouri Space Grant Consortium, and L. R. Dharani, faculty advisor.


It is well known that ceramics are strong, highly heat resistant, refractory materials. Unfortunately, they are brittle and fail catastrophically. However, the strength as well as fracture toughness of ceramics can be greatly improved with the addition of continuous fibers, thus obtaining ceramic matrix composites (CMC). Normally the addition of aligned continuous fibers to a matrix degrades the transverse (the direction 90° to the fiber axes) properties while greatly improving the longitudinal properties. It has been shown that the addition of whiskers to a continuous fiber CMC will improve moduli and strength properties in both the transverse and longitudinal directions. Any improvement in the transverse direction is a tremendous advantage as loads may not always act along the longitudinal fiber direction, thus avoiding the necessity for lamination and angle plies.

Strengthening ceramics by the addition of fibers and whiskers can hopefully produce a reliable refractory material that will offer service on the National Aerospace Plane (NASP) and other related space/hypersonic vehicles. If CMC can be shown to have high strength and toughness, they could fill a spot on the nosecap, leading edge surfaces as well as primary structures of the NASP.

Document Type


Presentation Date

16 Apr 1992