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Determining times‐to‐rupture under changing loading conditions by means of a modified life fraction rule
Author(s) -
Schäfer Ludwig
Publication year - 1986
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.198600806
Subject(s) - fraction (chemistry) , service life , constant (computer programming) , representation (politics) , service (business) , boundary (topology) , work (physics) , boundary value problem , mathematics , structural engineering , materials science , computer science , mathematical analysis , engineering , thermodynamics , chemistry , physics , composite material , economy , organic chemistry , politics , political science , law , economics , programming language
Previously the attempt has been made to improve the often inadequate accuracy of the life fraction rule (according to Robinson) applied to calculate the service lives under varying loading by introducing constants into the mathematical representation of the rule which take into account the influence of the material and the conditions of loading. Therefore, the calculated service lives are not real predictions. In this work description based on constants is dispensed with and only one boundary condition is indicated for the life fraction rule which is necessary and sufficient to calculate correctly any fractional damage and hence any service life under varying loading. The abbreviated wording of this boundary condition is: “To calculate a fractional damage the life fraction t i must be divided by a service life t m, i , the structural condition G i being the same.” The specimen will rupture as soon as the sum of fractional damages has attained unity: .