| Abstract Scope |
For the development of ceramic materials for hypersonic applications, reliable mechanical property data needs to be generated for materials and composites at elevated temperatures. From the perspective of ceramic materials, and consistent with ASTM standard testing methods, a Weibull plot to describe brittle failure requires 30 test specimens. This becomes untenable, although some level of statistical data is required. From the modeling perspective, however, strain data is of particular value, as a function of applied stress over an appropriate temperature range. While it would be beneficial to statistically know when failure might occur, the stress-strain data is of much greater value. To obtain stress-strain data, an indirect measurement was used that accommodated instrument compliance in the deflection measurements to calculate the tensile strain on the tensile surface of the 4-point monolithic flexure specimens. It is proposed that flexure specimens offer the best opportunity to obtain stress-strain data. |