Hello,
i try do connect our monocoque with the wheel bearing, where i want to set the loads, but i have massive problems with possible rigid body modes.
The wheel bearing is out of a rbe2 Element. Independent Node at the center.
The suspension rods are crod Elements. They are connected to the dependent nodes of the RBE2 Element with dof 1-3. On the other side to another RBE2 Element (independent node). The dependent nodes are connected to the monocoque.
The Pushrod is connected to a ball-joint and the ball-joint is connected to some 3D-Elements, which should demonstrate the bellcrank to turn the loads into the damper.
Can i send you the model, that you can help me solving the error messages?
Thanks in advance.
Henrik Alpmann
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Problem with rods, rbe, and joints
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Re: Problem with rods, rbe, and joints
Hi Henrik,
Yes, please use the dropbox below
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Re: 3D meshing basic problem
isn't there a way to define that two touching surfaces are connected before starting the meshing process. otherwise it would be a lot of work to select each element. especially when it is inside the yellow component like in my problem.
what I did so far was:
1. 2D automesh the inner component, than tetra mesh.
2. find faces (displayed), resulting in a new component "faces"
3. project all those elements to the component "faces"
4. tetramesh the outer component.
it seems there are still some small clashing areas. I used the same size/element properties
should I project to another component like the outer one?
How do I define contact surfaces?
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Re: 3D meshing basic problem
Student_1739
The step 3 above should be to project the elements you want to match to the outer component surface.
When there are two adjoining surfaces A and B of solids whose mesh has to match, solid 1 and solid 2, just mesh solid 1, extract the face elements of surface A , project the face elements to surface B of solid 2, them mesh solid 2
You can use Geometry > boolean if you have solids in order to combine the two solids so that they become one volume and there is full connectivity between the two bodies when you mesh.
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Re: Problem with rods, rbe, and joints
Henrik,
My first observations are that you may have to rethink your modelling approach of the wheel bearing,
Deleting the load on the rbe 2 eliminates the error, this error is usually due to insufficient constraints, wrongly defined spc etc
Secondly the warning about material orientation coordinate system can be eliminated by using an angle to define the material orientation.
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Re: 3D meshing basic problem
ok.
the problem is, that I only can choose onesurface of the outer component. so the projection is not working.![Image]()
![Image]()
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Re: 3D meshing basic problem
I just tried it again with an other surface. now it seems to work but as you can see in the close up it didn't work for the hole mesh
![Image]()
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Re: Normals of 3D elems using MAT9
it worked with MAT9ORT, thanks :)
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Re: Normals of 3D elems using MAT9
Thank you for updating :)
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Re: help with non linear materials, acceleration vs time loading, and more block tutorials in general.
I tried both ways but they did not work for me.
But now I have moved on to impacting the model by a rigid plate from top which is moving at 9 m/s. I have created a model but it requires very small time step and takes too long to run. Can you please offer some suggestions.. I have attached the hm file.
I am sorry to keep bothering you but my university doesn't have anyone who knows hyperworks well enough.
Thanks
![Image]()
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Re: help with non linear materials, acceleration vs time loading, and more block tutorials in general.
here it has an error saying the time step is less and almost equal to zero and terminates.
what is the impact time?
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Re: Normals of 3D elems using MAT9
i had some trouble that my solution failed to convert and checked my coordinate system and the nodes again.
When I assign the COSystem do I have to "set reference" or "set displacement"?
set reference changes the CP field in the grid card?
set displacement changes the CD field in the grid card?
I think set displacement is right but I am not sure. Can you help?
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Re: Problem with constraint force output using MATE function
Hi,
is the revolute joint on the grey shaft is connected via ground body? if that is the case its like the entire system except the bed is hanging? please correct me if I am wrong
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Re: Problem with constraint force output using MATE function
Hi,
the revolute joint indeed constrains the grey shaft to ground. Both the left and right horizontal axis (brown), however, are constrained to the grey shaft by both an inline joint and a parallel axes joint so that they are free to translate in Z direction and rotate about the Y axis of the body fixed marker (see lower end of the grey shaft).
Therefore, only the grey shaft is hanging. The rest is not.
The MDL source text in my first post (see link "Image") is attached by the trick described in the forum "How to use this forum?", see topic "How to upload *.hm files to the Support Forum". It can be saved and renamed to *.mdl.
Best regards
Matthias
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Re: Normals of 3D elems using MAT9
Tobias,
you can actually set both to the GRID/node(s). the set displacement references all changes in the DoF's and any vectorial notations to the grid which means the system created will be your analysis system. whereas the set reference defines the location of a particular GRID/node calculated with respect to the local system i.e., the system you have created instead of global system.
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Re: help with non linear materials, acceleration vs time loading, and more block tutorials in general.
You can make the impactor as a rigid by card editing the component.
also, when creating RBEs' make sure the independent node is not a part of the impactor. create a node a little offset to the impactor and connect to the elements.
In type 7 change the Istf to 4, this way solver will calculate the stiffness of the contact interfaces.
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Re: Problem with rods, rbe, and joints
please check the material consistency for isotropic materials. either give G or Nu. in one of your material cards the values are violating the relationship between E, G, Nu.
also, please check the coordinate system or change the orientation of the system.
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Re: 3D meshing basic problem
the problem is based on the geometry.
as you can see in the pictures, the lines of the two components are not the same.
is there a way to edit this before I proceed with the tetramesh and the face projection??
![Image]()
![Image]()
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Re: 3D meshing basic problem
Student_1739
Please send the model using the dropbox below,
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Re: 3D meshing basic problem
I just sent it
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