Rotational displacement BC problems

[LM290]

Hi all,

I am trying to apply a rotational displacement to a wheel which has been sectioned into 1/4. I have modeled this before so i know its possible, my issue is that it will not work again even with the same BC's etc. I basically have 1/4 of an alloy wheel with the outside rim surface fixed (to simply model tyre traction)then i apply a rotational displacement BC of 0.0175 radian (1 degree) to the inside surface which would contact the brake disc. I ran this simulation before as a proof of concept just before a meeting and did not manage to save it as i assumed it could be model very quickly again (it only took me 2 minutes to set up originally). Now when i try to run the simulation again it tells me in ABAQUS that the 'Degree of freedom 6 is not active in this model'. I know that 3D elements cannot be rotated but im not trying to rotate the elements just translate them about the z-axis. I have attached the images of the errors and the screens of my original simulation that i want to replicate.

 

[LM290]

PS. Please ignore the terrible mesh, i do intend on refining it later on

 

[IceBreakerSours]

I am confused because on the one hand you say you want to apply rotational boundary condition of 0.0175 radians and on the other hand you say " .. im not trying to rotate the elements just translate them about the z-axis". Let me provide two answers:

If rotation is what you want to assign to those elements:

Use Kinematic Coupling constraint between a node and nodes on the surface of interest. Then, apply this rotational boundary condition to that node.

If you want to translate the nodes along axis 3:

Use U3.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[LM290]

sorry if i have been unclear my knowledge of abaqus is very limited. According to the literature 3D elements do not have rotation, but im not trying to rotate the elements just apply a displacement to their position around an axis (Z). This is the reason why im confused about the error im receiving regarding my boundary condition. According to other forum responses the error is due to me trying to rotate the element and because elements have no rotation this flags an error. My goal is not to rotate the element but to displace it in an arc motion to give the effect of torque. Hopefully iv explained myself a little better.

 

[LM290]

This is a very short video i took of my first simulation that worked, it shows what i want to achieve.

 

[IceBreakerSours]

Nodes on continuum elements do not have rotational DOFs whereas nodes on structural elements possess rotational DOFs.

What you want to do is rotate the elements (not the nodes on those elements) on the surface around U3. You should use kinematic coupling between a reference node and the nodes on the surfaces of interest. And then apply UR3 to that reference node.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[LM290]

OK so should this be my process?

Do i select UR3 since this is the degree of freedom that i was the rest of the nodes to copy?

Then select the ref node again to apply the rotation

Thanks for all your help, this is for a final year project and iv never used ABAQUS to this extent before.

 

[IceBreakerSours]

Read the analysis manual for more, try a few things, ask your instructors .. Helping with course work is discouraged on a professional forum such as this one.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[LM290]

Cheers for the help. I got it working but used reference point as my 'ref node'. My issue now is with the symmetry conditions as my cyclic symmetry does not work, it just crashes as soon as the job is submitted. It is something to do with hardware acceleration apparently but i already have it turned off in the .ENV file.

 

[IceBreakerSours]

Try running the job file (.inp) from the command prompt as follows:

abaqus job=myJob cpus=4 memory=4000mb interactive

Depending on the version of your ABAQUS installation, the first keyword may be different. On mine, for example, it is abq611pr3 instead of abaqus.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[LM290]

Absolute hero ! Thank you so much for the help IceBreakerSours. Everything is working as it should! Out of curiosity, where is it running my inp. file with that command as it says there is 90 licenses and i only have acces to 14 usually ?

 

[IceBreakerSours]

Well, if you used the command prompt, the current directory is where the model must run.

If you running your model on a networked computer, then your school must have purchased so many licenses.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083