Effects of Architectural Variability on the In-Plane Strength of a Woven Ceramic Matrix Composite

摘要

Woven ceramic matrix composites such as SiC/SiC are candidate materials forrnfuture hypersonic vehicle systems such as thermal protection systems and aeropropulsionrnsystems. However, randomness in woven ceramic matrix compositernarchitecture has been found to cause large variability in stiffness and strength. Therneffect of varying architecture on the variability of in-plane tensile strength is studiedrnusing the Brittle Cracking Model for Concrete in the commercial finite elementrnsoftware, Abaqus. A maximum stress criterion is used to evaluate failure, and thernstiffness of failed elements is gradually degraded such that the energy required to openrna crack (fracture energy) is dissipated during this degradation process. While thernvarying architecture did not create variability in the in-plane stiffness, it doesrncontribute significantly to the variability of in-plane strength as measured by a 0.02%rnoffset method. Applying spatially random strengths for the constituents did notrncontribute to variability in strength as measured by the 0.02% offset. However, if thernstrength varies in larger clusters (rather than completely randomly), there are somernvariations in strength. While the architecture causes a larger amount of variability thanrnrandom constituent strength, the architecture and local constituent strength play arnsynergistic role in determining the strength of the composite.