The creep response of uni-directional fiber-reinforced ceramic composites: a theoretical study

Both the finite-element technique and the elastic-viscoelastic correspondence principle (in conjunction with the Hashin and Aboudi methods of calculating the effective elastic properties) methods have been used to calculate the effective creep properties of SCS6 (fiber)/SiC (matrix) composites and the results have been compared. In the finite-element technique, three different arrangements of fibers were used to study the effects of fiber arrangements on the creep properties of the composite. Effects of the fiber volume fraction on the creep behavior of composite were also studied. No significant difference was found in the longitudinal compliance, S11 (i.e. the compliance along the fiber axis), calculated from the five models. But, it was found that the fiber arrangement plays an important role in the transverse compliance, S22, and transverse shear compliance, S44. For S22, the correspondence principle method based on Aboudi method and the square array of fibers in the finite-element technique gave the upper and lower bounds, respectively. For S44, the square array of fibers in the finite-element technique and the correspondence principle method based on Hashin (for low volume fraction of fiber)/Aboudi (for high volume fraction of fiber) method gave the upper and lower bounds, respectively. The effects of fiber arrangements on S22 and S44 are explained by the strain energy and the energy dissipation due to creep.