[OT]: Failure Analysis - The bathtub looks more like a twintub

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[OT]: Failure Analysis - The bathtub looks more like a twintub

Justin Richards
I have ~20 years of failure data to hand for various devices including
PSU's, Amplifiers and Air Conditioners etc and was curious if there were
any interesting patterns.

Using Excel and its data analysis tools I have to conclude that the
histograms generally look more like a twintub or W rather than a bathtub.
There are lots of variables here and I may have biased myself into seeing W
shapes so not sure how valid all this is.

The middle peak shifts left or right by a year or so around the 10 year
mark depending on the item but then drops away until the failure rate
begins to increase again. The resulting graphs have more area under the
curve to the right (mostly) which I guess I was expecting, just wasn't
expecting the middle peak.

I thought it worthy of sharing and interested to know if others have
witnessed similar failure patterns that deviate from the bathtub

Justin
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