Submodeling allows analyzing a small region of a larger model with a more refined mesh. It involves solving a global model, creating a submodel with cut boundaries far from load and constraint areas, applying loads to the submodel boundaries, and verifying results. In ANSYS Workbench 14.5, submodeling is available directly in the interface, avoiding the need for APDL commands. It can be used to include more geometric details and refine meshes in critical areas compared to the global model.

1. Submodeling in ANSYS WorkBench 14.5
Roberto Silva
ESSS

2. TOPICS
• What is submodeling?
• Submodeling procedure
• Using submodeling in WorkBench Mechanical 14.5
• Comparison with Mechanical APDL submodeling

3. WHAT IS SUBMODELING?
• Submodeling is a modeling approach that allows to
solve a small part of a bigger model, with more
refined meshes and results.

4. WHAT IS SUBMODELING?
• Submodeling is based on St. Venant’s Principle.
– Far away from loading regions and constraint boundaries,
mechanical behavior is not affected.
– If submodel boundaries respect this principle, good
results are obtained.
http://pl.wikipedia.org/wiki/Plik:Zasada_de_Saint-Venanta.jpg

5. WHAT IS SUBMODELING?
• This technique allows an initial evaluation of a
coarser (and faster to solve) global model, followed
by a detailed analysis of regions of interest.
• The smaller submodel geometry allows one to:
– Use a more refined mesh at the critical regions to provide
better results;
– Include small geometric details (like welds) that are not
represented in the global model.

6. WHAT IS SUBMODELING?
• Submodeling has been available in Mechanical
APDL for years!
– NWRITE, CBDOF…
• WorkBench users needed to use
• It’s now available directly in Workbench Mechanical
14.5 interface.

7. SUBMODELING PROCEDURE
• Create and solve the global model;
• Create the submodel;
• Apply cut-boundary interpolation;
• Solve the submodel;
• Verify results and cut boundary position.

8. SOLVING THE GLOBAL MODEL
• No special setup for global model.

9. CREATING THE SUBMODEL
• To create a submodel analysis, Solution from Global
model is connected to Setup of the submodel.
Available in
Static Structural and
Steady-State Thermal
Analyses

10. CREATING THE SUBMODEL
• A Submodeling folder is automatically created, that
allows the definition of applied load.
– Loads must be applied on cut-boundary.

11. CREATING THE SUBMODEL
• Several options are similar to External Data.
– Display Source Points
– Mapping Controls
– Rigid Transformation

12. CREATING THE SUBMODEL
• Loads must be reapplied to submodel!
Pressure = 10 MPa
Force = 10 N
Pressure = 10 MPa
Force = 2.5 N

13. RESULTS VERIFICATION
• Submodel with same mesh size.

14. RESULTS VERIFICATION
• Submodel with more refined mesh size.

15. SUBMODEL – GEOMETRIC DETAILS
• The submodel geometry can be different from the
global model!
– As long as cut-boundaries are far away from region of
interest.
• This allows the user to include some geometric
details that are not considered in the global model.
– Welds
– Small fillets and chamfers
– Defects, like dents and cracks

16. SUBMODEL – GEOMETRIC DETAILS
• Example: pressure vessel with nozzle.
Weld fillets were
inserted in submodel

17. SUBMODEL – GEOMETRIC DETAILS
• Mesh comparison
61 126 nodes
30 101 elements
188 239 nodes
40 651 elements

18. SUBMODEL – GEOMETRIC DETAILS

19. SUBMODEL – GEOMETRIC DETAILS
Weld Region

20. SUBMODEL – 2D to 3D
• WorkBench submodeling can also be used to read
results from a 2D analysis in a 3D model.
2D Axisymmetric model 3D model

21. SUBMODEL – 2D to 3D
• Cut-boundary surfaces must include the original 2D
model faces.
Both revolution section
faces must also be selected!

22. SUBMODEL – 2D to 3D
• It’s necessary to select a cylindrical coordinate
system, aligned with the original plane.
2D Y-axis = 3D Z-axis
2D X-axis = 3D X-axis

23. SUBMODEL – 2D to 3D

24. WORKBENCH x MECHANICAL APDL
• PROS:
– User-friendly operation – No manual file handling!
– No need of APDL commands.
– Global mesh data can be adjusted – no need to worry
about origin position!
• CONS:
– No shell-to-solid submodeling yet…

25. WORKBENCH x MECHANICAL APDL
– … but it can be done with an ACT extension!
Available at ANSYS Customer Portal for download!

26. SUBMODELING FINAL REMARKS
• Submodeling is an useful technique to study large
structures in detail.
– Optimizes mesh refinement;
– Optimizes geometric detail modeling.
• The user must be careful to define suitable cut-
boundary limits.
– Submodel boundary must be far from critical regions.