Submodeling in ANSYS WorkBench 14

1 Submodeling in ANSYS WorkBench Roberto Silva ESSS. TOPICS. What is Submodeling ? Submodeling procedure Using Submodeling in WorkBench Mechanical 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.

2 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 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.

3 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 Pressure = 10 MPa Force = N. Force = 10 N. RESULTS VERIFICATION. Submodel with same mesh size.

4 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 188 239 nodes 30 101 elements 40 651 elements SUBMODEL GEOMETRIC DETAILS. SUBMODEL GEOMETRIC DETAILS.

5 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!

6 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 cut- boundary limits. Submodel boundary must be far from critical regions.