Category: Theory and definitions
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Optimal PM and spares strategies – exercises
Optimal maintenance strategies The exercises in this section follow from and extend the analyses conducted earlier in the Weibull exercises section. Age preventive replacement policy Discussion Most physical assets lend themselves to preventive maintenance based on usage. The greater the age the more stresses will have accumulated thereby diminishing an item’s failure resistance.…
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RA – Micro (day-to-day decision) analysis
Reliability Analysis: 2 dimensions (Statistical and probabilistic concepts) Reliability analysis is counting (slides) All types of analysis are about counting in one way or another. The elemental units of information that we count vary with each area of endeavor. Financial analysis is, of course, counting money and categorizing it in a variety of accounts that…
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Reliability trend yes Weibull analysis no
Building a Weibull model from a sample of data that covers a prolonged duration assumes that all failure times observed are “independently and identically distributed” (iid). That means that no change occurred in the inherent reliability of the item over the duration of the data. However there are at least three reasons why this assumption…
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Diagnostics versus prognostics
Where is the divide between the process of troubleshooting and that of predictive condition based maintenance? Both sets of procedures require condition data and knowledge of failure behavior. How do these distinct processes work with one another? Some confusion in the purchase and application of maintenance technology tools can arise when the particular problem lacks sufficient…
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Achieving reliability from data
Which, among limitless, maintenance related data is relevant to physical asset reliability improvement? Secondly, how do we transform that data into decision models for effective risk management? Finally, how do we continuously update those models for verifiable asset reliability improvement? These questions drive our relentless pursuit of new maintenance technologies. This article reports on Living RCM as a solution to the long standing problem of achieving…