National Research Council research associate, NASA Langley Research Center, Hampton, VA
Senior scientist, NASA Langley Research Center, Hampton, VA
Research associate professor, Rensselaer Polytechnic InstituteCairo University, TroyGiza, NY
Research engineer, Sverdrup Technology, Inc., NASA Lewis Research Center, Cleveland, OH
Pages: 17 Published: Jan 1993
Thermomechanical fatigue (TMF) data have been generated for a Ti-15V-3Cr-3Al-3Sn (Ti-15-3) material reinforced with SCS-6 silicon carbide fibers for both in-phase and out-of-phase testing. Significant differences in failure mechanisms and fatigue life are noted for the in-phase and out-of-phase testing. The purpose of the research reported in this paper is to apply a micromechanics model to analysis of the data. The analysis predicts the stresses in the fiber and in the matrix material during the thermal and mechanical cycling by calculating both the thermal and mechanical stresses and their time-dependent behavior. The rate-dependent behavior of the matrix was characterized and was used to calculate the constituent stresses in the composite. The predicted 0° fiber stress range was used to explain the composite failure. It was found that for a given condition, temperature, loading frequency, and time at temperature, the 0° fiber stress range may control the fatigue life of the unidirectional composite.
silicon-carbide fibers, isothermal fatigue, stress range, interface, residual stresses, in phase, out of phase, nonisothermal
Paper ID: STP24752S