Generating Material Properties From Flight Representative Structures

High-speed flight vehicles commonly use carbon / carbon (C/C) and carbon / silicon carbide (C/SiC) for structural components. These materials are chosen because of their superior structural properties at elevated temperatures. Most often, their properties are characterized using flat and thin material test plates. While this approach is convenient, it is not guaranteed to yield material properties that are representative of those observed on flight-representative components due to geometric differences. The Phase I effort demonstrated that curved specimens exhibited significantly different stiffness and strength than those that were flat, as observed in two loading modes via testing of 25 specimens. The proposed Phase II effort aims to further advance testing capabilities for complex specimens through a more expansive experimental and analytical program, focusing on the development of test methods for other critical loading modes for simply-curved and complexly-shaped specimens, at ambient and elevated temperatures. As in the Phase I effort, properties derived from flat and non-flat specimens will be compared for all loading modes investigated. The methods developed and data generated in this effort will also begin to establish a unified testing procedure for CMC materials that can be applied to current and future hypersonic vehicle development efforts.