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I need to run an analysis on a gear to see the tooth deflection induced by the shrink fit of the bore on to a shaft. Loading is easy just a simple pressure load applied on the bore, but how do I constrain it properly? I was thinking perhaps using a cyclic constraint? Any ideas?
Thanks,
Chris.
Running the simulation with a pressure load applied on the bore and selecting the check box for inertial relief under static analysis worked perfect!
Thanks,
Chris.
looking at the analysis results for stess everything looks as expected... what up with the deflections?
I’ve tried this a few different ways and can’t seem to get it right. My initial suggestion using cyclic symmetry is not a valid use of the tool, as I am only able to use it for a model analysis. So if I use a slice of the gear what type of constraint should I be using? Rigidly constraining the sides causes unrealistic stress concentration on those edges.
The last approach I tried was placing weak ground springs at 90 degree intervals on the top and bottom surfaces of the cylindrical feature. I was really surprised to see non-uniform displacement as was seen with using Inertial Relief and just the pressure force. So that appears to get back to what Steve mentioned regarding node locations. However that is confusing as the nodes should be the connection points of the springs. I can understand this while using Inertial Relief as the system chooses constraint point arbitrarily.
Still is it not possible to do an analysis on a pressure vessel? That’s essentially the problem, as Yuri pointed out the force is internal pressure the constraint is the hoop stress. But how can it be simulated in Mechanica?
Thanks,
Chris.
Thank-you for the information! I tried setting up the system as you’ve suggested, I’ve a 90 degree piece constrained on the symmetry surfaces. On one surface constrained X and Z, the other Y and Z, rotations are free. The displacement is closer to what I would expect, as you can see from the displacement picture, it expands radially but since it’s constrained on Z there is no deformation from top to bottom.
So I removed the Z constraint on those surfaces and placed 4 weak ground springs; the pressure load is 4500psi the springs have a stiffness value of 1 lbf/in (extensional), 1 in*lbf/rad (torsional). Looks good, is it valid? ...I think so. comments?
Thanks,
Chris.