Abaqus Explicit initial rotation
Abaqus Explicit initial rotation
(OP)
Dear all,
I have a very simple but at the same time a very frostrating problelm
I want to freely rotate the cilinder around its axis with an initial rotational velocity, while the inner surface is constrained to the reference point in the middle, as shown on the figure below. The simulation has to be done using Abaqus/explicit

I tried to simply use the coupling constraint to connect the inner surface with the reference point in the middle and prescribing the inital rotational velocity to the whole cylinder, but I get very strange results.
Since there is no boundary condition on load action on the cilinder, it sould freely rotate in space with its initial rotational velocity, but insted the results show very unstable results with high levels of stress, which doesnt make sence.
Does anyone know how this constrains should be modeled to get reasonable results?
I am also attaching the .inp of the problem.
http://www.filedropper.com/tryex2
Many thanks,
Uroš
I have a very simple but at the same time a very frostrating problelm
I want to freely rotate the cilinder around its axis with an initial rotational velocity, while the inner surface is constrained to the reference point in the middle, as shown on the figure below. The simulation has to be done using Abaqus/explicit

I tried to simply use the coupling constraint to connect the inner surface with the reference point in the middle and prescribing the inital rotational velocity to the whole cylinder, but I get very strange results.
Since there is no boundary condition on load action on the cilinder, it sould freely rotate in space with its initial rotational velocity, but insted the results show very unstable results with high levels of stress, which doesnt make sence.
Does anyone know how this constrains should be modeled to get reasonable results?
I am also attaching the .inp of the problem.
http://www.filedropper.com/tryex2
Many thanks,
Uroš





RE: Abaqus Explicit initial rotation
You have to define roatation initial velocity for all nodes not only for reference point.
You can do it with keyword *INITIAL CONDITIONS, TYPE=ROTATING VELOCITY.
Regards,
Bartosz
VIM filetype plugin for Abaqus
https://github.com/gradzikb/vim-abaqus
RE: Abaqus Explicit initial rotation
thanks for your reply. If you open the .inp file you can see that the initial velocity is defined to all the nodes not only the Reference point, so the problem shouldnt probably be there. Do you have any other idea maybe?
Regards,
Uros
RE: Abaqus Explicit initial rotation
Rob
Rob Stupplebeen
Rob's Engineering Blog
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RE: Abaqus Explicit initial rotation
This is a valuable point. Solid elements indeed do not have a rotational DOF. Your advice that proposes incorporation of an initial step could be a solution. I am though interested especially in the case where such step would not be needed,(since i will use this approach in a large assembly later, where such step would not be efficient) and the initial velocity vould be prescrived in the initial conditions.
Since it seemes you have some experiences, would you have any other sugestion?
Regards,
URoš
RE: Abaqus Explicit initial rotation
I mainly work on medical devices such as implants and the body doesn't usually spin.
I hope this helps.
Rob
Rob Stupplebeen
Rob's Engineering Blog
Rob's LinkedIn Profile
RE: Abaqus Explicit initial rotation
if you look at picture at the first figure you can see that cylindrical coordinate system has already been made.
I know it is a very strait forward problem that should not take a lot of efford to come accros, but it has been bodering me for weeks now. Any more suggestions would realy help me out.
Regards,
Uroš