Creat CBUSH with cylindrical coordinate
Altair Employeedear all
I want to creat a CBUSH element to simulate a rubber with axial stiffness and radial stiffness. I tried cylindrical coordinate, but the result is same as rectangular coordinate.
How could I solve this problem? Thanks!
---this model is built with cylindrical coordinate.
---this model is built with default rectangular coordinate.
Answers
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Could you share your model with us?We will take a look and update you.
Regards
Rahul R
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hi, Rahul R
Thank you very much, now I have already uploaded the models. Could you help me?
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You can define the local cylindrical system and then flag the ID of this in the 9th (CID) field of CBUSH card.
CID > 0 overrides GO and Xi. Then the element x-axis is along T1, the element y-axis is along T2, and the element z-axis is along T3 of the CID coordinate system. If the CID refers to a cylindrical coordinate system or a spherical coordinate system, the grid GA is used to locate the system. If for cylindrical or spherical coordinate, GA falls on the z-axis used to define them, it is recommended that another CID be selected to define the element x-axis.
Find attached a sampled deck defining Bush elements wrt a cylindrical system, all the nodes are assigned to a cylindrical displacement system => the GA node of the CBUSH is assigned a cylindrical displacement system too hence the orientation vector is implicitly attached to cylindrical system via GA.
Regards
Rahul R
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Thank you very much. But I sitll have a problem. I define four cylindrical coordinates. Each mount has its own coordinates, for all the axial stiffness and radial stiffness
of mounts are defined by its own coordinates. Why the result is same as rectangular coordinate? It is wrong to define axial stiffness and radial stiffness with rectangular coordinate. I don't know why.
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What results you are compairing?I see you have performed modal analysis & zero length bush elements you have in your deck.
Regards
Rahul R
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First thank you very much answering my question.
The attachment two files contain CBUSH elements, one is created with cylindrical coordinates, the other one is created with rectangular coordinate.
The pbush property defined same as follows
PBUSH 1 K390.0 0.0 751.0 0.0 0.0 0.0
for the model: axial stiffness should be 751 and radial stiffness should be 390
for the model: stiffness on X direction of local coordinate should be 390 and on Z direction should be 751
Because the coordinates are different, I think the result should be different. but it seems not like that. I don't know why.
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