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Comparison of 3P‐Weibull parameters based on J C and K J C values
Author(s) -
LARRAINZAR C.,
BEREJNOI C.,
PEREZ IPIÑA J.E.
Publication year - 2011
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2010.01533.x
Subject(s) - weibull distribution , weibull modulus , equivalence (formal languages) , brittleness , mathematics , exponentiated weibull distribution , materials science , function (biology) , statistics , metallurgy , discrete mathematics , evolutionary biology , biology
The characterization of fracture toughness of ferritic steels in the ductile‐to‐brittle transition is problematic due to the scatter of test results. Several proposals using Weibull statistics have been made, some of them in terms of J and others in terms of K ; some authors employ a two parameters Weibull function (2P‐W), while others use a three parameters function (3P‐W), although ASTM E1921 uses 3P‐W in terms of K with two fixed parameters to determine the Reference Temperature To. An analysis about the relationship between Weibull distributions expressed in terms of J and K is presented in this paper. It is shown that if the J C results follow a 3P‐W, their equivalent values do not exactly fit a 3P‐W function obtained by means of a simple transformation of the three parameters. Nevertheless, an approximated 3P‐W function in K terms is proposed in this work. It fits very well with the transformed values and their parameters are related to the ones expressed in J terms. In case the experimental results follow a 3P‐W in , a similar analysis can be performed. For the particular situation of a 2P‐W, there is an exact equivalence between the distributions in terms of J and K , being the Weibull slope in terms of K twice the slope in terms of J .