On the use of the Weibull and the normal cumulative probability models in structural design

In this paper, the Weibull and the normal cumulative probability are discussed and compared in relation to the analysis of the fracture toughness KIC. It is shown that, in the normal distribution, KIC can take negative or zero values, causing complications in structural design. In the Weibull distribution, this does not happen and its lower limit KICL can be determined without problems. So, the Weibull cumulative probability represents reality in a better form. Finally, comparing experimental data with both distributions, it is found that the Weibull probability is more economics in terms of structural design.