Vibration Fatigue Testing

[Raddy13]

I'm getting ready to send a part out for vibration fatigue testing, but I've never done this before and I'm a little unsure how to set the parameters. The part is being mounted on an engine and I've already run a test and collected vibration data for the mounting location. Now from that, how exactly do I go about scaling the data to simulate the lifetime fatigue from the vibration? Is there a way to scale the PSD? Do I take an FFT and just increase the amplitude? I'm a little unclear of how to do this, so any help is greatly appreciated!

 

[rb1957]

the simple approach is the ensure that the maximum cycle measured in less than the endurance limit (if you're looking for infinite life).

if you're looking for finite life, i'd use a rainflow algorithim to reduce your measured spectrum to a manageable bunch of max/min cycles; use miner's rule to determine the damage accumulated in your test ... sum(n/N); then the life = (test duration)/sum(n/N)

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