抄録
Approximate functions for estimating the variances and degrees-of-freedom associated with the slow crack growth parameters n, D, B, and A as measured using constant stress rate (″dynamic fatigue″) testing were derived by using propagation of errors. Estimates made with the resulting functions and slow crack growth data for a sapphire window were compared to Monte Carlo simulations. Comparison indicated that linearization of the constant stress rate equation is not required for good estimates of the variances of parameters n and D by propagation of errors. However, good estimates of the variances of the parameters B and A requires linearization. This was a result of the skewed distributions of B and A. Parametric variation of the input parameters was used to determine an acceptable range for using the approximate solutions.
