RBE2 AND JOINTS
Altair Employeehi,
what is the difference between joints and RBE2 elements?? while using RBE2 if we select(tick) dof checkbox does it mean that we are allowing that dof?
Answers
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The RBE2 element defines a rigid body with independent degrees-of-freedom that are specified at a single grid point and with dependent degrees-of-freedom that are specified at an arbitrary number of grid points. The first grid listed on the RBE2 is the independent grid point and all 6 degrees of freedom are used. The CM field is used to specify the components of the following dependent grids.
For RBE2 the constraint DOF’s will be transferred from independent node(Master) to dependent node/s (Slave).
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Hi Jahnavi,
Yes when you Uncheck the Dof of dependent nodes of RBE2. Careful when using Dofs on dependent nodes as this may result in local deformation.
So rotation at independent node produce a translation at dependent nodes and translations at then dependent nodes affect rotations at the independent node.
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can u please tell me about joints(fixed) also??
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What type of joints you are using?
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I'm using fixed type.does that allow any dof??
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Fixed joints has all Dof constrained. You can create an RBE and constraint in all dofs will realize to fixed joint.
The joints which are available in OptiStruct 1D page are meant for Multi body simulation.
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hi,
I'm using both rbe2 and celas1 elements in one model then it is showing an error that there is some internal massless mechanism.how can i get rid of that?Can i use cbush elements for rigid connections??which property should i assign to that??
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When i'm using fixed joints it is showing that there are no MBD cards and all the joints are neglected
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can u pls tell the difference between rigids and rigidlink but it is not there in 1D but if we select elements by configuration it is showing rigids and rigid link separetely
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Jahnavi,
Looks like you are using JOINTS which are MBD entities for a FRF anlalysis. This is not compatible.
Also, there is no much space available to write scratch files in your working directory. You need to create a temperory directory to write scratch files.
Refer to this below post:
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Altair Forum User said:
can u pls tell the difference between rigids and rigidlink but it is not there in 1D but if we select elements by configuration it is showing rigids and rigid link separetely
A rigid has one Independent node and only one dependent node where as for a rigidlink variable dependent nodes are connected to independent node.
Both are rigid elements.
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