Creo Simulate > Modeling Structure and Thermal Problems > Meshes > Native Mode Meshes > Controlling an AutoGEM Mesh > Isolate for Exclusion (IEAC)
  
Isolate for Exclusion (IEAC)
Click Refine Model and then click the arrow next to Control. Click Isolate for Exclusion. The Isolate for Exclusion Control dialog box opens. Use this control to detect and isolate the singularities in a model as an Isolate for Exclusion AutoGEM Control (IEAC).
Singularities are areas of theoretically infinite stress or temperature flux and are undesirable because they can skew analyses results. For example, point loads in shells or solid models create singularities, or stress concentrations. In this case, your analysis solution may primarily reflect these stress concentrations, hampering your ability to focus on overall stress behaviors that you may be more interested in.
You can ignore such singularities when calculating convergence and measures during analysis by excluding elements grouped as an IEAC mesh control. Creo Simulate ignores the stresses and possible displacements from measure computations for the elements that touch the references defined by the IEAC, by limiting the polynomial order of the edges of the elements and possibly ignoring the stresses when normalizing the errors during a single pass analysis. The Single Pass Adaptive (SPA) algorithm also ignores stresses in excluded elements when computing the local relative error estimate. By ignoring singularities in a model during analysis, you can save analysis time and get accurate results for the areas outside the singularities.
Specify the following information on the Isolate for Exclusion Control dialog box:
Name—Specify the name for the AutoGEM control or use the default name.
Preselect Singularities—Identifies the specified type of singularities in the model simultaneously and populates the collector in the dialog box. For example, if you select reentrant corners, the appropriate edges or points or both are added to the collector. Similarly for point loads, the points that are loaded by point loads are added to the collector.
Creo Simulate detects the singularities of type Point Loads and Point Constraints by default in Structure mode. In the Thermal mode, the Point Heat Loads and Point Prescribed Temperatures are set by default.
Model Geometric Entities—Selects datum points, edges, datum curves, datum surfaces, volume regions, or parts on the model to group as an IEAC mesh control.
If Preselect Singularities is selected, Creo Simulate identifies all the specified types of singularities in the model simultaneously and populates the collector in the dialog box. Select geometric entities on the model to add them to the selected entities or to replace all the preselected entities with other model entities.
Isolation for Shells—Refines the shell mesh by separating shell elements adjacent to singularities using the Automatic, None, or Maximum Element Size options. The default is Automatic.
Isolation for Solids—Refines the solid mesh by separating solid elements adjacent to singularities using the None or Maximum Element Size option. The default is None.
Exclude—Specifies whether or not the elements that isolate the selected geometric references are excluded elements. To exclude these elements, check the Exclude check box on both the IEAC definition dialog box and on the Analysis definition dialog box. Note that this option does not affect the AutoGEM mesh creation.
Creo Simulate groups all the selected singularities in the model as an IEAC mesh control and the corresponding model entities are tagged with a icon in the graphics window. If the elements that touch the references defined by the IEAC are excluded, Creo Simulate ignores the stresses and displacements from measure computations. Optionally, it may limit the polynomial order of the edges of the elements and ignore the stresses when normalizing the errors during a single pass analysis.
You can create multiple IEAC mesh controls in a model and group different types of singularities. All such singularities are isolated during AutoGEM mesh creation.
To exclude the isolating elements that are defined by the IEAC mesh control from an analysis, you must select the following items:
The Exclude check box on the Isolate for Exclusion Control dialog box and
The Exclude Elements check box on the Excluded Elements tab of the corresponding analysis definition dialog box.
As an option to exclude elements is available on both the IEAC mesh control and the analysis definition dialog box, you can optionally exclude some isolated regions and not others by creating multiple IEACs, and selecting various combinations of IEACs during analysis. When defining multiple IEACs for the analysis, you should consider various guidelines and behavior.
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