FEA on stubshaft with impeller

[schmt1i]

Hi all,

I'm looking to do an FEA on a stubshaft that has an impeller at the end of it. Mostly, I'm looking to simulate the torque from the motor on the shaft along with the forces of the impeller. Keeping the impeller in place is a key between the shaft and impeller. The problem I'm having with this, is that

a) I have the basic version of Solidworks, which does not allow for an easy way to do this

b) When I tried putting the torque from the motor on the key, Solidworks thinks it's a bending moment (not true), so I put another key in the bottom and applied the same force to twist the shaft, but when the part is actually made, there is only one key, which will void any results I get.

c) When I tried modeling the impeller as a part of the shaft, it says there is stresses at the point where the shaft and impeller meet, which does actually happen.

Has anybody had experience with this?

Thanks

 

[JMirisola]

Going off of you only having basic SolidWorks, you must be using SimulationXpress. If this is the case, there's not much you can do short of what you've done. SimulationXpress is very limited in the options you have as far as applying fixtures and forces, which you've already discovered. Also, it's meant only to be a first-pass test and you shouldn't base your design solely on the results you get. However, the test you did by adding the second keyway will give you a rough idea where your design stands, but you'd need to do hand calcs, or use a complete FEA solver, to be sure.


Jeff Mirisola, CSWP
Design Manager/Senior Designer
M9 Defense
My Blog

 

[schmt1i]

JMirisola, Thanks for the reply!

What we ended up doing is creating the shaft with a circular knob on the end of the shaft to simulate the impeller with two cutouts and put a force on each cutout to simulate the torque from the motor via the impeller. As it turns out, the torque on the shaft had little effect compared to the moment we were previously simulating, so all of our shafts were a little over-engineered for their purpose, but this way we know they won't fatigue.