A Generalized Weibull CDF  
Author D. Gary Harlow




Abstract As reliability and durability become more critical for the design and life assessment of engineered components and systems, the need for more accurate modeling is exacerbated. Time dependent damage accumulation has been a long– standing concern, especially for significant structural components. This is intensified by variability in material properties, loading conditions, and other sources of uncertainty. Analyses of data predominately have been empirical, but mechanical behavior, such as creep, creep– rupture, fracture, or fatigue, require more sophisticated modeling. A generalized phenomenological cumulative distribution function (cdf) for lifetime, which is a combination of mechanical breakdown, weakest–link theory, and classical reliability theory, is investigated. The model is a generalization of the classical accelerated life model in which covariates are included to account for physical attributes that directly influence component lifetime. Even though the proposed cdf was first introduced nearly six decades ago, it has been used very little for modeling damage growth in materials. The first part of this paper is a review of the structure and properties of the cdf. In order to demonstrate its utility, the remaining portion of the paper considers examples subject to fatigue.


Keywords Breakdown rules, Fatigue, Load dependent parameters, Stress–life analysis, Step–stress loading, Weibull distribution
    Article #:  20278
Proceedings of the 20th ISSAT International Conference on Reliability and Quality in Design
August 7-9, 2014 - Seattle, Washington, U.S.A.