Use the RBE3 panel to create, review, and update RBE3 elements. The Update subpanel allows you to edit the connectivity, DOFs, and weight for each node of the element.
RBE3’s are interpolation constraint elements, where the motion of a dependent node is defined as the weighted average of the motions of a group of independent nodes. The dependent degrees of freedom and weighting factors can be specified or automatically calculated based on the geometry. RBE3 elements are element config 56 and are displayed as lines between the dependent node and the independent node(s) with RBE3 displayed at the dependent node of the element.
RBE3’s are typically used to distribute loads applied on the dependent node amongst the selected independent nodes.
| Note: | The dependent node cannot be directly constrained, as this would lead to a double-dependency for that node. |
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Panel Usage
The rbe3 panel consists of two subpanels, listed along the left-hand edge. Each subpanel has entry fields arranged in two columns in the center of the panel, as well as a set of command buttons on the right-hand edge. Work flow proceeds in columns from left to right.
Changes made in subpanels are persistent until you leave the rbe3 panel (changes are not lost if you switch between subpanels). Changes made in one subpanel do not affect corresponding criteria in the other subpanel.
Subpanels and Inputs
The rbe3 panel contains the following subpanels and command buttons:
Panel Inputs
Input
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Action
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dependent (switch)
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The switch offers two options: calculate node and node selector.
| • | Calculate node creates the dependent node at the weighted average (root-mean-square) location of the selected independent nodes. |
| • | The nodes selector allows you to pick the desired dependent nodes from your model. |
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independent nodes
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Use this entity selector to pick the desired independent nodes from your model.
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dependent dofs: (checkboxes)
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Select the Degrees of Freedom to transfer from the dependent node to the independent nodes.
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weight =
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The decimal proportion (0-1) of the force and moment loads distributed from the independent nodes to the dependent node for the selected DOF’s.
| Note: | The proportion of moment load distributed will also be affected by the geometry (distance) between the dependent and independent nodes. |
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elem types =
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Click this field to display a pop-up menu of valid element types, then click the desired type. Valid types depend on your current solver profile.
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Panel Inputs
Input
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Action
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elem
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Use this entity selector to pick the desired RBE3 element.
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connectivity
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This option determines which additional fields display in the third column of the panel:
| • | Indicate which element you want to update by selecting it on your model, or click elem to display the extended entity selection window. |
| • | To change the dependent node, click node under dependent: and pick the node that you want to be the dependent node. |
| • | To add additional nodes, click nodes under independent: and use the left mouse button to pick the nodes to add to the element. |
| • | To remove independent nodes, click nodes under independent: and use the right mouse button to pick the nodes to remove from the element. |
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dofs
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This option determines which additional fields display in the third column of the panel:
| • | Indicate which element you want to update by selecting it on your model, or click elem to display the extended entity selection window. The current DOFs applied to each node of the RBE3 element are displayed. |
| • | If the change to the DOFs applies to all the nodes of the RBE3 element, select the desired DOFs and click set all. |
| • | If the change is to individual nodes, click the toggle to set individual or select to type. |
| - | If you select set individual, use the checkboxes to select the DOFs you want to apply and then pick the desired nodes to which you want to apply the selected DOFs. |
| - | If you select select to type, pick the DOF numbers displayed by the node that you want to change in the graphics area. The existing DOF values are replaced with a numeric text box; type in the DOF numbers that you wish the node to use, then press ENTER. |
| Note: | When you update the DOFs, only legal DOF values are accepted. |
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weight factors
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This option determines which additional fields display in the third column of the panel:
| • | Indicate which element you want to update by selecting it on your model, or click elem to display the extended entity selection window. The weight of each node of the RBE3 element is displayed. |
| • | If the change to the weight applies to all the nodes of the RBE3 element, enter the desired weight in weight = and click set all. |
| • | If the change is to individual nodes, click the toggle to set individual or select to adjust. |
| - | If you select set individual, enter the weight in weight = and then pick the desired nodes to which you want to apply the weight. |
| - | If you select select to adjust, click the weight displayed by the node that you want to change. Left-click to increment the weight, or right-click to decrement it. Alternatively, left-click-and-drag to rapidly change the value--drag upwards for higher values, and downwards for lower ones. |
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elem types
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This option determines which additional fields display in the third column of the panel. In this case, only the elem types = field displays; click it and pick a valid element type to change the RBE3 to. Valid types depend on your current solver profile.
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The following action buttons appear throughout the subpanels:
Button
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Action
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create
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Creates the new RBE3 to your specifications.
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update
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Change the selected RBE3 to use the currently defined characteristics. Once updated, you can no longer reset to the original values--you can only reset to the updated values.
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reject
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Undoes the most recent create action.
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review
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Click this button, then pick an RBE3 element in the graphics area. The selected RBE3's characteristics display in the subpanel's entry fields.
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reset
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Reset the entry fields to their starting values (the RBE3 element's currently assigned values, as opposed to any changes you might have made without clicking update.)
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