4+ Take-Aways About Failure Patterns, Failure Mechanisms, and Perception.
Alejandro Erives
Creating the future in maintenance, reliability, and your organization.
I recently posted a quiz about failure (here).
The focus was on 4 failure patterns (Wear Out, Random, Fatigue, & Infant Mortality).
Fatigue and Random failure mechanisms appeared to be the hardest to identify.
An example mechanism for fatigue can be "consistent corrosion cracking mechanism present during normal operations, such as CI-SCC".
A common trait among many fatigue mechanisms is that there is frequently a condition governing initiation (say of a crack) and a separate mechanism governing deteriotation (or propogation for a crack).
Random failure mechanisms on the other hand are characterized by a sporadic condition.
spo·rad·ic [adjective]: occurring at irregular intervals or only in a few places; scattered or isolated
This sporadic condition should generally be sufficient to cause failure at any time - otherwise the failure would present itself as a different failure pattern (i.e. break-in, fatigue, or wear out).
Wear-out appeared to be the easiest to identify in the quiz.
An example of wear out given in the quiz was "Routine exposure to corrosion mechanism in batch operations".
In some applications (in my experience), wear-out is a very common issue - in particular in industries with very corrosive or harsh environments.
Typical histories in RCM texts tend to focus on random or non-age related failure patterns.
Perceptions of the predominant failure mode, however, is generally split (see figure below).
Past studies generally did not include chemical, manufacturing, or refining industries (source of my quiz/survey participants).
If you are interested in understanding (and managing) failure in your organizations then you need to understand the failure patterns (i.e. statistics / Weibull).
To quote W. Edwards Deming, "It is not enough to do your best - you must know what to do, and then do your best."
So, which failure pattern is most prevalent in your organization?
What is Weibull Analysis and what does it have to do with failure?
Weibull analysis is a method of finding patterns in the distribution of failures over time.
In addition to determining what type of failure pattern you may have, Weibull quantifies the failure rate (% reliability).
Blackstart Reliability offers software and service related to Weibull Analysis. Contact me if you'd like to know more.
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5 年Dear Alejandro, The identification of failure patterns was useful in a time when we didn′t have adequate tools for statistical analysis. Currently we have powerful statistical analysis tools. The probabilistic fault models can show the existence of potential failure modes and through a good root cause failure analysis you can to elaborate action plans to eliminate or to mitigate them. Think about.