Optimization of sample number for Weibull function of brittle materials strength

The estimation of the parameters of the Weibull function was investigated with regard to reliability. The sample number, confident level, and relative error of estimated parameters are three key factors and should be involved for evaluating the strength of brittle materials. The results indicated that the scatter of scale parameter was much less than that of shape parameter. The relationship of sample number, confident level, and relative error of shape parameter was established. The lower limit of sample number should be more than 20 in order to decrease the scatter of shape parameter.