1 / 20

The Art of Matrix Reduction

The Art of Matrix Reduction. How to create a super-element matrix in ANSYS. ME 501 Project Michael Tonks Alan Mortensen. Summary. Background Matrix Reduction Substructure Analysis Creating Super Elements in Ansys Leading Edge Example Conclusions. FEA Difficulties.

asher-mccormick
Download Presentation

The Art of Matrix Reduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Art of Matrix Reduction How to create a super-element matrix in ANSYS ME 501 Project Michael Tonks Alan Mortensen

  2. Summary • Background • Matrix Reduction • Substructure Analysis • Creating Super Elements in Ansys • Leading Edge Example • Conclusions

  3. FEA Difficulties • Complex parts have large stiffness matrices • Analyses with large parts are cumbersome • Large Number of nodes • Many DOFs • Large matrices • Difficult to invert • Take up large disk space

  4. Create Super Element Matrices • The equivalent stiffness matrix is condensed by eliminating interior nodes that have no loads • Matrix reduced to create equivalent super-element matrix • Small and easy to analyze • Contains all important information

  5. Create Super Element Matrices • The equivalent stiffness matrix is condensed by eliminating interior nodes that have no loads • Matrix reduced to create equivalent super-element matrix • Small and easy to analyze • Contains all important information

  6. Substructure Analysis • Large structures divided into sections • Each separate section analyzed to find stiffness matrix • Super elements created and reassembled for full structural analysis

  7. How to create Super Elements in • Step 1: Create and Mesh Geometry

  8. How to create Super Elements in • Step 2: Specify Analysis type

  9. How to create Super Elements in Select File Name Select option to print Matrix • Step 3: Select Option to Print Stiffness Matrix

  10. How to create Super Elements in Choose DOFs • Step 4: Choose Masters and Master DOF’s • Choose Master Nodes • Choose Master DOF’s

  11. How to create Super Elements in Choose file name Select Full contents • Step 5: Solve in Current LS • Super Element Saved in .sub file • Super Element Matrix retrieved in List file • Menu Path: List – Other – Superelem – Data

  12. How to create Super Elements in • Super Element Stiffness Matrix:

  13. How to create Super Elements in • Super Element Stiffness Matrix:

  14. Example • Leading Edge Skin • Supplied by Boeing Phantom Works • Modeled in Pro/E • Imported as IGES into Ansys Actual Part Pro/E Model Ansys Model

  15. Meshed Part • Skin meshed using Shell Elements • Shells given thickness of actual part

  16. Master DOF’s Chosen • Part rigidly constrained along bottom edge • Master DOF’s chosen along one side • Location for spar • In X, Y, Rot Z Master DOF’s

  17. Super Element Matrix • Problem solved in Ansys • Stiffness Matrix Shown in Ansys List File • Originally 683 Nodes, 2049 DOF’s • Reduced to 24 Nodes, 72 DOF’s

  18. Conclusions • Ansys can be used to do Substructure Analysis • Make complex problems easier to solve • Ansys can output the super element stiffness matrix • Useful for other types of analysis

  19. Future Research • Investigate different data output methods for super-element matrix • Develop Matlab program to format super-element matrix for linear algebra • Combining super-elements in assemblies for FEA analysis

  20. Questions?

More Related