Re: What would cause a fan blade to fail?
Posted by:
JimmieD
(66.81.29.---)
Posts: 1,090
Date: July 03, 2009 01:46PM
How can it not be metal fatigue?
http://www.materialsengineer.com/CA-fatigue.htm
The part does not have to part into separate pieces for metal fatigue to be present, or to be the cause. Just like bending a piece of wire back & forth until it finally breaks, there's that point long before breakage & separation where extreme metal fatigue has occured, from cycles of bending, like vibration. The frequencies of flex & bending in a fan blade would change throughout engine rpms.
Just a nick or two in the fan blade occurring when it was punched out and/or stamp formed could weaken one blade in relation to the others. Add in a possible, even likely imbalance and years of engine revs and you have exactly what's needed for catastrophic failure.