ABSTRACT
The interest in new high-performance aircraft and turbine engines over the last several years, which has brought attention to titanium matrix composites (TMCs) as a candidate for high-temperature structural applications, brings with it a number of questions related to design for fatigue. For fatigue life prediction in this material system, the role of thermal stresses induced by the large difference in coefficient of thermal expansion between fiber and matrix must be considered when the material is subjected to thermal cycling. This chapter reviews and evaluates approaches that have been developed for life prediction in TMCs. The life prediction methodologies considered here are limited to the case of smooth bar fatigue, with no consideration being given to the problem of the propagation of a single dominant crack. Fatigue under mission spectrum loading, which has received relatively little attention, is addressed as an extension of life modeling under isothermal fatigue and thermomechanical fatigue.
