Estimator type and population size for estimating the Weibull modulus in ceramics

Analysis of fracture data in ceramics can be made by applying probabilistic theories. In order the fracture probability to be expressed an estimator must be used. For economic reasons it is also necessary, the population size for estimating the shape ceramic parameter, to be found. In the present work a number of estimators and sets of different sample populations of kaolin ceramics are tested against the stability of the weibull shape parameter. The 2-parameter and 3-parameter Weibull functions and the Neville function were compared for best fitting of results. It seems that modulus remains almost constant in the range of the specimen numbers tested and a minimum number of about 30 specimens is acceptable for reliability predictions at least for the examined type of ceramic. (C) 1998 Elsevier Science Limited All rights reserved.