In the process of creating a model in a structural analysis design program, sometimes user has to repeatedly delete some elements and then add others:
- for example, while using a previously created geometric model which is being corrected;
- the prototype does not exactly match the chosen structure;
- the user just made a mistake in the model design.
The model is being packed for: 'throw together' coincident nodes and elements; non-refundable exclusion of removed nodes and elements from the design model. When unpackaged scheme is analyzed, removed nodes and elements are considered as non-existent, but their numbers are saved until the packing is done.
Also, using the Pack model dialog box, you can delete stiffness types, materials, and groups coupled DOF that are not assigned to any object of the model.
Dialog box Pack model () can be opened from the Create and edit tab on the Edit panel. It controls the packing parameters of the created model.
In order to mark in the scheme the elements that will become incorrect due to "throw together" nodes and mark the nodes merging of which will lead to this, click on the button .
To work with incorrect finite elements during the 'throw together' process, you can activate one of the radio buttons:
- do not delete elements with incorrect geometry;
- delete elements with incorrect geometry;
- correct if possible.
Also, in the Pack model dialog box there is a command for selecting (on model) elements with incorrect geometry -; and for restoring elements with incorrect geometry - .
The 'Throw together' checkbox gives access to control the following parameters:
- pack precision for nodes: if the distance between nodes is less than the value specified in this box, then these nodes are packed into one, in this case node numbers for appropriate elements are changed;
- in order not to pack elements into one element (for example, several one-node FE type 51 located in the same node), select the Ignore elements with different stiffness types check box;
- in order not to pack nodes with Coupled DOF (degrees of freedom) into one node, select appropriate check box;
- in order not to pack nodes of rigid bodies into one node, select appropriate check box;
- to pack the current fragment, select the Only for fragment check box;
- in order not to pack selected objects of design model, select Except selected nodes and elements check box.
Select the check boxes under Eliminate from design model to do the following:
- dangling nodes ' after the pack procedure all nodes that do not belong to any element will be completely removed from the model while the rest of nodes will be renumbered;
- nodes and elements that were deleted ' after the pack procedure all nodes and elements that were deleted (removed from analysis) will be completely removed from the model while the rest of nodes and elements will be renumbered;
- unused stiffness types ' after the pack procedure all unused stiffness types will be completely removed from the model while the rest of stiffness types will be renumbered;
- unused materials ' after the pack procedure all unused design materials will be completely removed from the model while the rest of design materials will be renumbered;
- unused groups of Coupled DOF ' after the pack procedure all unused groups of Coupled DOF will be completely removed from the model while the rest of groups will be renumbered.
To specify the decimal values to which coordinates should be rounded, in the Modularity for coordinates of nodes area, click Reduce coordinates of nodes to module.
To automatically make a document recover file AutoRecover file, select the AutoSave before pack procedure check box.
To cancel all defined parameters and restore parameters accepted by default, click the Parameters by default button.
Please note that as a result of packaging, the history of creating the model is destroyed
Finite elements of model united into a single element after the pack procedure are coloured red.
Fig. 1. Pack model dialog box
If you find a mistake and want to inform us about it, select the mistake, then hold down the CTRL key and click ENTER.