http://popups.lib.uliege.be/1373-5411/index.php?id=2750 Publications of Auteurs M. Purgailis fr 0 http://popups.lib.uliege.be/1373-5411/index.php?id=3198 In this paper, a control theory is used for planning inspections in service of fatigue-sensitive aircraft structure components under crack propagation. One of the most important features of control theory is its great generality, enabling one to analyze diverse systems within one unified framework. A key idea, which has emerged from this study, is the necessity of viewing the process of planning in-service inspections as an adaptive control process. Adaptation means the ability of self-modification and self-adjustment in accordance with varying conditions of environment. The adaptive control of inspection planning process in service of fatigued aircraft structures differs from ordinary stochastic control of inspection planning process in that it attempts to reevaluate itself in the light of uncertainties in service of aircraft structures as they unfold and change. Thus, a catastrophic accident during flight can be avoided. Wed, 11 Sep 2024 17:02:22 +0200 Thu, 10 Oct 2024 16:27:31 +0200 http://popups.lib.uliege.be/1373-5411/index.php?id=3198 http://popups.lib.uliege.be/1373-5411/index.php?id=2836 For important fatigue-sensitive structures of aircraft whose breakdowns cause serious accidents, it is required to keep their reliability extremely high. In this paper, we discuss inspection strategies for such important structures against fatigue failure. The focus is on the case when there are fatigue-cracks unexpectedly detected in a fleet of aircraft within a warranty period (prior to the first inspection). The paper examines this case and proposes stochastic models for prediction of fatigue-crack growth to determine appropriate inspections intervals. We also do not assume known parameters of the underlying distributions, and the estimation of that is incorporated into the analysis and decision-making. Numerical example is provided to illustrate the procedure. Tue, 03 Sep 2024 15:00:02 +0200 Thu, 10 Oct 2024 16:16:27 +0200 http://popups.lib.uliege.be/1373-5411/index.php?id=2836 http://popups.lib.uliege.be/1373-5411/index.php?id=2741 Based on a random sample from the Weibull distribution with unknown shape and scale parameters, lower and upper prediction limits on a set of m future observations from the same distribution are constructed. The procedures, which arise from considering the distribution of future observations given the observed value of an ancillary statistic, do not require the construction of any tables, and are applicable whether the data are complete or Type II censored. The results have direct application in reliability theory, where the time until the first failure in a group of m items in service provides a measure regarding the operation of the items, as well as in service of fatigue-sensitive aircraft structures to construct strategies of inspections of these structures ; examples of applications are given. Fri, 30 Aug 2024 15:11:10 +0200 Thu, 10 Oct 2024 16:28:03 +0200 http://popups.lib.uliege.be/1373-5411/index.php?id=2741