1 / 21

3.2 Material Models

3.2 Material Models. Material enhancements in ANSYS 5.7 include: A. Material Definition GUI B. Hyperelasticity C. Metal Plasticity D. Viscoplasticity E. User Material Subroutine for 18x Elements. Material Models A. Material Definition GUI. New GUI for material model definition

aretha-reilly
Download Presentation

3.2 Material Models

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. 3.2 Material Models • Material enhancements in ANSYS 5.7 include: A. Material Definition GUI B. Hyperelasticity C. Metal Plasticity D. Viscoplasticity E. User Material Subroutine for 18x Elements Training Manual 001419 15 Aug 2000 3.2-1

  2. Material ModelsA. Material Definition GUI • New GUI for material model definition • Applicable to all linear and nonlinear materials (except ANSYS/LS-DYNA and FLOTRAN fluids) • Logical tree structure sorted by discipline and behavior • Associates all properties (MP’s and TB’s) for a material model, which is treated as a single entity Training Manual 001419 15 Aug 2000 3.2-2

  3. Material Models… Material Definition GUI • Definition and editing of models • Intuitive definition of complex relationships (combination models) • Dynamic interface, e.g., {stress vs. strain} vs. temperature • Provides a framework for future expansion • Experimental data input • Support for external material database (XML, proprietary…) Training Manual 001419 15 Aug 2000 3.2-3

  4. Material Models… Material Definition GUI • Models and disciplines All models in database All available materials grouped by discipline Training Manual 001419 15 Aug 2000 3.2-4

  5. Material Models… Material Definition GUI • Subgroupings Expanded folder shows material model contents Materials are grouped by behavior Training Manual 001419 15 Aug 2000 3.2-5

  6. Material ModelsB. Hyperelasticity Background: • Existing (5.6) mixed U-P elements (56, 58, 74, 158) have limited application • Assumed not incompressible • Pressure is NOT a DOF (eliminated before solution) • Penalty based formulation causes problems • Input via • TB,MOONEY,mat,ntemp,npts • Material property dialogs Training Manual 001419 15 Aug 2000 3.2-7

  7. Material Models… Hyperelasticity New in ANSYS 5.7: • Mixed U-P formulation added to all 18x family of elements (except beams which are naturally excluded). • Poisson’s ratio of 0.5 allowed (incompressible) • Compressible and incompressible parts are two separate formulations • Lagrange multipliers for Pressure DOF • Includes all relevant stress states • Input via: • New TB,HYPER option* • New material definition GUI *TB,BOYCE has been moved to TB,HYPER Training Manual 001419 15 Aug 2000 3.2-8

  8. Material Models… Hyperelasticity • New formulation also offers more hyperelastic material models: • Mooney-Rivlin • Ogden • Neohookean • Polynomial • Arruda-Boyce • User hyperelasticity Training Manual 001419 15 Aug 2000 3.2-9

  9. Material Models...Hyperelasticity • Example: Axisymmetric plug using Ogden model Training Manual 001419 15 Aug 2000 3.2-10

  10. Material Models...Hyperelasticity • Example: Cook membrane problem using Mooney material Training Manual 001419 15 Aug 2000 3.2-11

  11. Material ModelsC. Metal Plasticity • ANSYS 5.7 represents a significant change in the philosophy of material implementation: Keep material behavior separate from element technology. • Allows complex behavior to be simulated by combining simple behaviors • Easier to maintain existing material models and add new ones • New plasticity model: Hill type anisotropy Training Manual 001419 15 Aug 2000 3.2-12

  12. Material Models...Metal Plasticity Hill type Anisotropy • Must be combined with another form of plasticity such as bilinear isotropic hardening • 6 input constants define the ratio of the yield value in each orthogonal direction to that specified on the hardening model. • Elastic portion of model may be isotropic or orthotropic Training Manual 001419 15 Aug 2000 3.2-13

  13. Material Models...Metal Plasticity • Example - uniformly loaded stainless steel plate with constant pressure BISO only BISO with Hill anisotropy Training Manual 001419 15 Aug 2000 3.2-14

  14. Material Models… Metal Plasticity • Plasticity options available in 5.7: • Isotropic hardening laws • Kinematic hardening laws • Anisotropic plasticity • Viscoplasticity • User material Training Manual 001419 15 Aug 2000 3.2-15

  15. Material ModelsD. Viscoplasticity • Types of viscoplasticity in ANSYS 5.7: • Creep • Implicit Creep • Explicit Creep • usercreep for implicit and usercr for explicit • TB,ANAND for 106, 107 and 108 only • TB,RATE for 18x elements • Peryzna • Peirce • User Material for 18x elements Training Manual 001419 15 Aug 2000 3.2-16

  16. Material Models… Viscoplasticity • BISO only Training Manual 001419 15 Aug 2000 3.2-17

  17. Material Models… Viscoplasticity • BISO plus Perzyna Training Manual 001419 15 Aug 2000 3.2-18

  18. Material Models… Viscoplasticity • BISO plus Peirce Training Manual 001419 15 Aug 2000 3.2-19

  19. Material ModelsE. User Material • Why User Material? • Not all materials can be included • some material behavior proprietary • need to apply limited resources to general behavior • Gives users the ability to create custom material behavior • Subroutine usermat*, which was beta at 5.6, is now released. • Note: Some differences exist between beta and released versions. 5.6 users should re-create user material at 5.7. *Not to be confused with USERPL, USERCR, etc Training Manual 001419 15 Aug 2000 3.2-20

  20. Material Models… User Material • Subroutine usermat • For 18x elements only, i.e, only structural analyses at the present time • User must specify both linear and nonlinear properties • Requires relink of ANSYS (use ANSCUSTOM script) • Demonstration routine includes BISO plasticity Training Manual 001419 15 Aug 2000 3.2-21

More Related