Materials behavior engineer, GE Aircraft Engines, Cincinnati, OH
Pages: 16 Published: Jan 1990
A preliminary investigation of the mechanical behavior of a Nicalon/CAS [O/90]2s laminate at 20 and 815°C has been performed For monotomc and cyclic tension, a sequence of progressive damage has been identified as 90° ply degradation, followed by transverse matrix cracking in the 0° plies and nonlinear strain deformation. Monotonic and cyclic behavior at 815°C was degraded due to embnttlement of the fiber/matrix interface. Longitudmal stiffness remained fairly constant following initial degradation on the first fatigue cycle. Surface crack density and inelastic strain deformation were found to be functions of applied stress and, thus, useful in monitoring damage progression. At 20°C ultimate strength increased, and stram-to-failure decreased, following cyclic damage. For uniform umaxial tension, Nicalon/CAS behaves in a manner amenable to evaluation by the critical element method of fatigue life analysis.
ceramic composite material, fatigue (materials), damage mechanisms, critical element, characteristic damage state, inelastic strain, crack density, composite materials, thermal properties, mechanical properties
Paper ID: STP25397S