Submodeling in ANSYS WorkBench 14.5. Roberto Silva. ESSS ... Submodeling
procedure. • Using submodeling in WorkBench Mechanical 14.5 ... Page 12 ...
Submodeling in ANSYS WorkBench 14.5 Roberto Silva ESSS
TOPICS • What is submodeling? • Submodeling procedure • Using submodeling in WorkBench Mechanical 14.5 • Comparison with Mechanical APDL submodeling
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.
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.
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.
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.
SUBMODELING PROCEDURE • Create and solve the global model; • Create the submodel; • Apply cut-boundary interpolation; • Solve the submodel; • Verify results and cut boundary position.
SOLVING THE GLOBAL MODEL • No special setup for global model.
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
CREATING THE SUBMODEL • A Submodeling folder is automatically created, that allows the definition of applied load. – Loads must be applied on cut-boundary.
CREATING THE SUBMODEL • Several options are similar to External Data. – Display Source Points – Mapping Controls – Rigid Transformation
CREATING THE SUBMODEL • Loads must be reapplied to submodel!
Pressure = 10 MPa
Force = 10 N
Pressure = 10 MPa
Force = 2.5 N
RESULTS VERIFICATION • Submodel with same mesh size.
RESULTS VERIFICATION • Submodel with more refined mesh size.
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
SUBMODEL – GEOMETRIC DETAILS • Example: pressure vessel with nozzle.
Weld fillets were inserted in submodel
SUBMODEL – GEOMETRIC DETAILS • Mesh comparison
61 126 nodes 30 101 elements
188 239 nodes 40 651 elements
SUBMODEL – GEOMETRIC DETAILS
SUBMODEL – GEOMETRIC DETAILS Weld Region
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
SUBMODEL – 2D to 3D • Cut-boundary surfaces must include the original 2D model faces.
Both revolution section faces must also be selected!
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
SUBMODEL – 2D to 3D
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…
WORKBENCH x MECHANICAL APDL – … but it can be done with an ACT extension!
Available at ANSYS Customer Portal for download!
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 cutboundary limits. – Submodel boundary must be far from critical regions.
