Rigid body constraint
Moderator: bernd
Forum rules
and Helpful information for the FEM forum
and Helpful information for the FEM forum
- Pauvres_honteux
- Posts: 728
- Joined: Sun Feb 16, 2014 12:05 am
- Location: Far side of the moon
Re: Rigid body constraint
What do you guys say about separating what to be connected from the connection properties?
That way it opens up for one connection and multiple properties. Where only one property is active per calculation session, i.e. it speeds up the process. Especially good for showing your collegues different scenarios in a short time frame.
Hmm, perhaps it also opens up for time based calculations where the properties change over time?
That way it opens up for one connection and multiple properties. Where only one property is active per calculation session, i.e. it speeds up the process. Especially good for showing your collegues different scenarios in a short time frame.
Hmm, perhaps it also opens up for time based calculations where the properties change over time?
Re: Rigid body constraint
What properties are you talking about ? Rigid body comstraints don’t have any, their definition is just setting which nodes should be connected to which reference point. Couplings are a bit more complex as you can also define weight for the connection and choose DOFs to be constrained but that’s it when it comes to settings.
Or do you have something different in mind than those constraints ?
Or do you have something different in mind than those constraints ?
Re: Rigid body constraint
From user point of view yes, but from developer point of view:NewJoker wrote: ↑Wed Aug 11, 2021 11:31 am What properties are you talking about ? Rigid body comstraints don’t have any, their definition is just setting which nodes should be connected to which reference point. Couplings are a bit more complex as you can also define weight for the connection and choose DOFs to be constrained but that’s it when it comes to settings.
Or do you have something different in mind than those constraints ?
- we create a new FEM constraint object
- this object will have some attributes (properties)
- reference face
- reference point
- depending if existing constraints are used or not some more properties to held the force and fix
These properties will be attached to the object. The object will be passed to the writer and the writer will write the input file.
Attached a example of the last whole new object implementation: https://github.com/FreeCAD/FreeCAD/comp ... 282db7c8c6
Re: Rigid body constraint
after the first commit the object runs, there is just no gui tool to ceate (python need to be used) it and no task panel and no unit test. Eventually for a real object for sure they are needed too.bernd wrote: ↑Wed Aug 11, 2021 11:43 am Attached a example of the last whole new object implementation: https://github.com/FreeCAD/FreeCAD/comp ... 282db7c8c6
Re: Rigid body constraint
@NewJoker I'm working on this right now but it's been a while using INP files. Could you attach a sample file with how it should all work? Doesn't have to be too complicated (in fact better if it isn't): say an 8- element cube with rigid body constraint applied on one face.
My latest (or last) project: B-spline Construction Project.
Re: Rigid body constraint
Sure, I attached the file. Thank you for your interest in this topic. Please let me know if you need any help with CalculiX's syntax or other issues regarding the implementation.jnxd wrote: ↑Thu Oct 27, 2022 5:00 pm @NewJoker I'm working on this right now but it's been a while using INP files. Could you attach a sample file with how it should all work? Doesn't have to be too complicated (in fact better if it isn't): say an 8- element cube with rigid body constraint applied on one face.
P.S. The example involves torsion so the load is applied to ROT NODE of rigid body constraint.
Re: Rigid body constraint
very cool, If the obeject is implemented it would be great just to include such simple example to the FEM python examples. I even did it before I started wich such object implementation to have something to test with.
If you have any question come up ...
bernd
If you have any question come up ...
bernd
- ebrahim raeyat
- Posts: 621
- Joined: Sun Sep 09, 2018 7:00 pm
- Location: Iran
- Contact:
Re: Rigid body constraint
Hi. I thinks this is what calculix must be done, am I wrong?
Re: Rigid body constraint
From CalculiX's side, it's just a matter of applying *BOUNDARY or *CLOAD to a node used as a REF NODE (for translational DOFs) or ROT NODE (for rotational DOFs). So, in the attached example, you can find:ebrahim raeyat wrote: ↑Mon Oct 31, 2022 10:50 am Hi. I thinks this is what calculix must be done, am I wrong?
Code: Select all
*CLOAD
22, 1, 1000
Re: Rigid body constraint
Thanks for the offer. A question came up: this particular constraint requires a new node to be created; (how) can this be done within write_constraint_rigidbody.py? This node will need to have a number different than existing nodes, and there could be multiple rigid bodies, which would need different nodes to be added.
My latest (or last) project: B-spline Construction Project.