Rotaional Speed to Overcome Shrink Fit

Hi Folks,

First time posting on this forum. I am a novice Mathcad user. I have Prime 3.0 and am having problems with a solve block. I suspect the problem is how I have the worksheet set up.

I have two equations for the maximum tangential stress on a hub connected to a shaft. First equation is stress due to press fit. Second equation is stress induced by rotation of hub. I am trying to solve for the rotational speed where the stress from the shrink fit is overcome.

I have solved this problem by hand. Now I am trying to have Mathcad save me the time required to rearrange equations.

I would appreciate any advice you could provide. I have attached the file.

Regards,

Bill