Category: Reliability Analysis
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Failure probability prior to attaining MTTF
The article “What is the scale parameter” showed that 63% of randomly failing items or items adhering to Weibull failure behavier will fail prior to attaining their MTTF. Generally speaking, the MTTF is not a good decision guide for the age replacement of an item. The following shows that for age dependent failure behavior (e.g.…
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Problem statement
When to maintain? (Slides) In the casino hall that we call “maintenance” we are faced with choices. Risk is associated with each decision we take. We might say that maintenance is the art and science of managing risk. The choices we make day to day affect the organization’s bottom line profitability. Pursuing the casino metaphor…
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RCM – Living RCM: Achieving reliability from data
1 The objectives of LRCM (slides) Living RCM was created to address two vital yet unresolved issues not addressed by initial RCM or the EAM. First, observational data entered on the work order is, generally speaking, of insufficient quality for Reliability Analysis (RA) and decision modeling. Efficient maintenance management requires model based decision making. Otherwise…
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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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Weibull exercises
We have seen that reliability analysis is about counting failure mode instances of failure and preventive renewal. The EAM should be our “counting machine” but, thus far, has not fulfilled that role for the reliability engineer. In these simple exercises we will perform reliability analysis and draw certain conclusions. Perkins marine diesel engine Problem background…