What is the Impact of Imbalance Force on a Rotating Shaft?

[minger]

I'm doing some rotordynamic work with an outside guy is doing some bearing research for us. I sent him my steady-state response as a function of frequency, and he's almost taken aback by the bearing loads. He said that long ago he did the analysis with another engineer (no longer here) and they were an order of magnitude lower.

As a quick back-of-envelope, could I simply do:
$$F = mr\omega^2$$
To get an idea of the magnitude of forces involved at a frequency?

 

[FredGarvin]

For a point imbalance. Sure. You can throw in a bit more realistic situation by making it a couple imbalance by just adjusting it to

$$T= 2mrl \omega^2$$

 

[minger]

Good enough for me, thanks.