Rotating axle in Ansys

[Garvin]

I really hope some of you may be able to help me with this problem...


I have an axle which is supported at one end in a bearing and at the other end there is a clutch.
The problem is that the axle is not straight, which results in the axle bending. It is kind of S-shaped. (Badly turned)
What I would like to do, is simulate this axle turning, and then be able to observe how it is performing. (How much it is bending).

I would really appreciate it, if anyone could give me some hints how to solve this problem in Ansys, or any other FEM program, for that matter.


Best regards

Jan

Best regards,
Jan L

 

[Garvin]

Hi...

I have looked high and low, for some clues how to solve this problem, but haven't been able to find anything.

Any input whatsoever would be greatly appreciated.
If I haven't been specific enough, or explained the problem well enough, please let me know?





Best regards,
Jan L

 

[Drej]

A basic analysis could be to constrain the axle at the bearing end with a frictionless support, whilst applying a rotational velocity to the entire axle (see the OMEGA command). This should simulate the turning motion of the axle and give you some offset bending. Without a more precise desciption of your system/results required etc., it's difficult to give more advice.

Cheers,

-- drej --

 

[Garvin]

Hi
Thank you for your response...

Goal:
I wan't to make the axle turn around it's axis, and then find the reactions at it's support(s). I would also like to observe how it acts dynamically, at different velocities in order to find it's natural frequencies and mode shapes. (Maybe a normal modal analysis is adequate for finding the natural frequencies???)


What I have tried to do so far is this:

Model:
I have modelled the axle in a CAD program, imported and meshed it in Ansys. (Swept mesh)

Constraints:
At one end (Which is straight)I have made a local cylindrical coordinate system, rotated the nodes on the outer surface at that end into same coord. system., then constrained those nodes for radial movement. Finally I have constrained the nodes on the end surface for axial movement. (same end)

Load(s):
I have applied global inertia (OMEGA) around the ideal axis of the axle.

Solution:
?????
I tried to specify a transient analysis, but I have no experience so far, with transient analysis, so....


I think that I'm on the right way, as far as the setup of the model goes, but I get somewhat lost when it comes to the solution.


Best regards,
Jan L

 

[edebs71]

Garvin,

Did you manage to get it work?

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)

edebs71

 

[Garvin]

No... Unfortunately I haven't managed to get it to work... :-(

I'm still looking into it though.

Best regards,
Jan L

 

[edebs71]

Hi Jan,

After a dicussion with Drej (see "Cylindrical Constraints in Ansys" post that I initiated a couple of days ago. It seems that you cannot use angular acceleration or velocity as a load in a transient analysis in ansys and expect your part to rotate.

knowing that linear acceleration and velocity works in a transient analysis (I've tried it, the part did move as expected).

This doesn't make sense to me at all. I guess every software has its limitation.

Cheers,
Elias