Ansys_submodel_tutorial.pdf
- 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.