In this paper, we demonstrate a method by which computationally intensive micromechanical simulations of stress-rupture processes in ceramic matrix composites can be reduced to simpler analytical expressions. In this procedure, the results obtained from the micromechanical simulations are treated as inputs to a phenomenological model. The phenomenological model can then be used to predict degradation under more complex environments, which would normally require simulations. To demonstrate the technique, three conditions are examined: (1) the effect of changing stress level during the test, (2) the superposition of two damage mechanisms, and (3) the combination of (1) and (2). The results of the simple phenomenological model are then compared to the results of micromechanical simulations.