Cyclic fatigue of a model feldspathic porcelain

Objectives. This study was conducted to evaluate the fatigue parameters of a model porcelain based on the Weinstein patent using cyclic fatigue and to compare the parametric values obtained from cyclic fatigue tests with those from dynamic fatigue tests previously reported by Fairhurst et al. (1993). Methods. Cyclical biaxial flexure of 1 mm thick and 12 mm diameter disks was performed at 37°C in distilled water at a frequency of 4 Hz with constant stressing rates between a minimum and maximum stress. Three groups of samples (50, 40, 40) were tested with a maximum stress of 51, 47, and 43 MPa, respectively. The crack growth exponent, n, and the scaling constant, σfo, were derived from the regression constants obtained from a linear regression of the logarithm of the median time to failure with the logarithm of the maximum stress. Results. No significant differences were found between the cyclic fatigue parameters, n and σfo, derived from the median time to failure and those obtained from dynamic fatigue data. Significance. Within the limits of error in this determination, the median cyclic fatigue life can be estimated by the use of fatigue parameters obtained from dynamic fatigue testing.