Cylindrical constraints in Ansys
Cylindrical constraints in Ansys
(OP)
Hi,
I'm trying to simulate a 2D rotating disk on a polishing Jig.
I created and meshed the disk (hollow disk). I rotated the nodes to Active cylindrical coordinate.
1. I applied Ux = 0(radial coordinate) on inside circumference of the disk.
2. I applied global acceleration
3. ran a transient analysis for 0.5 seconds.
The disk did not move at all, it seems that ansys does not understand radial constraints (it asigns the constraints only in the X direction not radially)
Could you please tell me what am I doing wrong.
thank you in advance.
I'm trying to simulate a 2D rotating disk on a polishing Jig.
I created and meshed the disk (hollow disk). I rotated the nodes to Active cylindrical coordinate.
1. I applied Ux = 0(radial coordinate) on inside circumference of the disk.
2. I applied global acceleration
3. ran a transient analysis for 0.5 seconds.
The disk did not move at all, it seems that ansys does not understand radial constraints (it asigns the constraints only in the X direction not radially)
Could you please tell me what am I doing wrong.
thank you in advance.





RE: Cylindrical constraints in Ansys
RE: Cylindrical constraints in Ansys
I rotated all nodes into the cylindrical system (is this correct?)
I only applied the Ux=0 constraint to the inner circle
What am i missing?
RE: Cylindrical constraints in Ansys
No. As my post says, only rotate the inner circle nodes and apply your radial constraint here.
RE: Cylindrical constraints in Ansys
I did that (rotated only the inner circle nodes and applied the radial contraints. I appplied a global angular acceleration of 3.14 rd/sec^2 on the disk and ran a transient analysis for 0.5 seconds. When I checked the position of a specific node on the disk (it didn't move at all).
I animated the result over time (the disk didn't rotate at all).
I've tried the same procedure on a model moving in a straight line (X-direction) and everything looks OK (the model moved during this 0.5 seconds as it is supposed to).
Please help.......
RE: Cylindrical constraints in Ansys
RE: Cylindrical constraints in Ansys
I'm applying the acceleration DOMEGA as a stepped load in the transient analysis. Normally the disk should start rotating 'till it reaches a OMEGA = DOMEGA * time.
I tried a solid disk (constrain its central node radially) and applied the angular acceleration for 0.5 second as a stepped load. The disk started to rotate but the final rotation did not coincide with:
Theta = 0.5 * DOMEGA * time^2 + OMEGA(i)* time + Theta(i) (in this case OMEGA(i) and Theta(i) = 0)
Something doesn't make sence here (I don't think I'm missing any required step)
Any thoughts?
NOTE: I ran another transient analysis:
a) Load Step1: I specified a rotational displacement on the inner node during time t, to get an initial rotational velocity.
b) Load Step2: I removed the Uy constraints and ran for another T = 1 second
Ran an animation to see if the disk will continue to move(at the speed calculated from Load Step1) after Load Step 1 and guess what it didn't.
I thought that ANSYS could handle something like that easily.
RE: Cylindrical constraints in Ansys
Why do you need to run a transient analysis for this type of loading? My thoughts (as before) are: that you CANNOT use DOMEGA within a transient analysis and expect to see your disk rotating. If you want to analyse acceleration ONLY, I would use DOMEGA as a 'static' load applied within a static-type analysis. Why do you need to model the acceleration as a transient anyway? it doesn't make sense to me (maybe you have a simple explanation for this?). You will not see the model rotating because that is not the nature of the usage of this command. This command issued within a static analysis (ANTYPE,0) will give you what you need. What you should see here are stresses in the disk due to centripetal forces. Although this command is very much valid for transient analysis (for example, as a constant throughout loading), using this command in the way you have described is meaningless, and I would reconsider your strategy.
Cheers,
-- drej --
RE: Cylindrical constraints in Ansys
I'm trying to analysis the stresses induced in a Silicone Chip resting on a polishing disk as it accelerates from zero speed to a specified one at time T).
that is why I need the acceleration in a transient analysis.
Thank for your help,
Elias