Strategy: Specifying Polynomial Order for a Multi-Pass Adaptive Analysis

When you define a multi-pass adaptive analysis, you can specify the minimum and maximum polynomial order that the Creo Simulate engine uses for each edge. The default is a minimum of 1 and a maximum of 6. In general, use the default values.

If the analysis does not converge on the first run, review the results to understand why it did not converge. See Reviewing the Results for information on reviewing convergence graphs, stress and flux fringe plots, and p-level results.

A run usually fails to converge for one of two reasons:

• A singularity is present and the engine is trying to capture a high stress or flux gradient.

• A highly distorted element is trying to capture a smooth stress or flux field.

In either case, the best solution is to refine the mesh through the Isolate for Exclusion AutoGEM Control, recreate the mesh, and rerun the analysis. You can use items on the Isolate for Exclusion AutoGEM Control dialog box to divide the elements near the local effects, such as concentrated loads, cracks, reentrant corners, and thickness discontinuities between shells. Optionally, you may specify the isolating elements to be excluded, so that the singularity does not adversely affect the results of the analysis.

If this proves difficult, increasing the maximum polynomial order is an alternative. (But if you require high polynomial levels in areas of interest, you should consider refining your mesh). With smaller elements, convergence is more likely to occur and thus will ensure better results in the areas of interest.

For transient thermal analyses, if you suddenly switch on heat loads and convection conditions, your changes will adversely affect analysis convergence. If all heat loads and convection conditions are smooth functions that are zero at the start of the analysis, the engine will generally select smaller values for the p-orders. For more information on how to smooth these functions, see Ramping of Heat Loads and Convection Conditions.

Return to Polynomial Order or Multi-Pass Adaptive Convergence Method.