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# Calculating the maximum angular velocity of a solid cylinder before it disintegrates2

## Calculating the maximum angular velocity of a solid cylinder before it disintegrates

(OP)
Hey guys,

I trying to find out the maximum angular velocity (with respect to its radius) of a material prior to its disintegration. Im currently using this hoop stress equation for a solid cylinder (Hoop stress = (3 + [v/(1-v)]) * ([density*angular velocity^2*radius^2]/8). As there is not current value for the hoop stress, I have substituted it with the materials maximum tensile strength. Does anyone have any other suggestions?

### RE: Calculating the maximum angular velocity of a solid cylinder before it disintegrates

The matter of stresses in rotating cylinders is widely treated in literature: do a google search.
As far as the failure criterion is concerned, if your goal is to insure that no failure occurs, I think your only option is to avoid yield. Otherwise if you want to predict the speed for rupture, then good chance, it's a complex phenomenon with various uncertainties.

prex
http://www.xcalcs.com : Online engineering calculations
https://www.megamag.it : Magnetic brakes and launchers for fun rides

### RE: Calculating the maximum angular velocity of a solid cylinder before it disintegrates

2
Look for high speed flywheel papers. Rate of change of speed is also a factor.
You cannot have any yielding, which means staying will below the engineering yield strength.
Once you get yielding the shape changes and so do the stresses, and then things start to come apart.
In the real world these fail because of internal imperfections that cause high local stresses well before the bulk stress becomes an issue.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

### RE: Calculating the maximum angular velocity of a solid cylinder before it disintegrates

(OP)
Great! Thanks guys

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