Experimental Validation of the Relationship between Parameters of 3P-Weibull Distributions Based in JC or KJC

摘要

The characterization of fracture resistance of ferritic steels in the ductile to brittle transition zone is problematic due to the great scatter of test results.The statistical treatment in the literature is mainly based on the Weibull distribution,but some authors based their analysis on such a distribution with two parameters (2P-W),while others use a three parameters Weibull distribution (3P-W).Besides this,it is not homogeneous the use of these distributions in terms of J or K,and in general is acceptable that the Weibull slope for a K based distribution is twice the corresponding slope for the distribution based on J values.In previous works,the authors have shown that this relationship between slopes is not valid,except for the case of a 2P-W distribution,and have proposed a new factor (ξ ) different from two that is calculated once the three parameters of the 3P-W distribution are estimated.In this paper it is demonstrated,using datasets with 100％ cleavage from the Euro Round Robin in order to analyze cases where the weakest link model is valid,that this new factor works quite well,and that even when 3P-W distributions based on J and K values are not equivalent,both could be used to describe the results of fracture mechanics toughness tests.