Premium
Fitting fatigue data with a bi‐conditional model
Author(s) -
Cova M,
Tovo R
Publication year - 2017
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/ffe.12541
Subject(s) - quantile , reliability (semiconductor) , range (aeronautics) , fatigue limit , quantile function , function (biology) , cumulative distribution function , probability density function , confidence interval , limit (mathematics) , extension (predicate logic) , paris' law , reliability engineering , mathematics , structural engineering , statistics , computer science , engineering , fracture mechanics , mathematical analysis , physics , power (physics) , evolutionary biology , biology , programming language , aerospace engineering , crack closure , quantum mechanics
The formulation of a probability‐stress‐life (P‐S‐N) curve is a necessary step beyond the basic S‐N relation when dealing with reliability. This paper presents a model, relevant to materials that exhibits a fatigue limit, which considers the number of cycles to failure and the occurrence of the failure itself as statistically independent events, described with different distributions and/or different degree of scatter. Combining these two as a parallel system leads to the proposed model. In the case where the S‐N relation is a Basquin's law, the formulations of the probability density function, cumulative distribution function, quantiles, parameter and quantile confidence interval are presented in a procedure that allows practically any testing strategy. The result is a flexible model combined with the tools that deliver a wide range of information needed in the design phase. Finally, an extension to include static strength and applicability to fatigue crack growth and defects‐based fatigue approach are presented.