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S.S. Yang and J.K. Lee

FEMLAB and its applications. S.S. Yang and J.K. Lee. Oct. 25, 2005. Plasma Application Modeling Lab. POSTECH. Contents. Introduction of FEMLAB. How to run FEMLAB. How to draw geometry (2D and 3D). How to generate meshes. Examples (Electro-static cases).

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S.S. Yang and J.K. Lee

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  1. FEMLAB and its applications S.S. Yang and J.K. Lee Oct. 25, 2005 Plasma Application Modeling Lab. POSTECH

  2. Contents Introduction of FEMLAB How to run FEMLAB How to draw geometry (2D and 3D) How to generate meshes Examples (Electro-static cases) Parallel capacitor with dielectric circle Plasma display panel structure Spherical capacitor Plasma Application Modeling@ POSTECH

  3. FEMLAB (COMSOL Multiphysics) COMSOL Multiphysics Ver. 3.2 (Package name is changed) 1995 1999 2000 2001 2002 2003 2004 2005 COMputer SOLutions (COMSOL) is a Swedish-based software company in partnership with Mathworks. They developed the PDE Toolbox for use with MATLAB, and more recently the FEMLAB computing environment, also MATLAB based. Now, FEMLAB is upgraded and program name is changed to “COMSOL Multiphysics” FEMLAB has a powerful interactive environment for modeling and solving various kinds of scientific and engineering problems using finite element method (FEM) based on partial differential equations (PDEs). Plasma Application Modeling@ POSTECH

  4. FEMLAB - Key features  Fast, interactive and user-friendly Java-based graphical user interface for all steps of the modeling process  Powerful direct and iterative solvers based on state-of-the-art C++ technology  Linear and nonlinear stationary, time-dependent and eigen-value analyses of large and complex models  Total freedom in the specification of physical properties, whether as analytical expressions or functions  Unlimited multi-physics capabilities for coupling of all types of physics  General formulations for quick and easy modeling of arbitrary systems of PDEs  Built in CAD tools for solid modeling in 1, 2, and 3D  CAD import and geometry repair of DXF (vector data format) and IGES (neutral data format) files  Fully automatic and adaptive mesh generation with explicit and interactive control of mesh size  Extensive model libraries that document and demonstrate more than 100 solved examples  Parametric solver for parametric studies and efficient solution of highly nonlinear models  Interactive post-processing and visualization using high performance graphics  Smooth interface to MATLAB Plasma Application Modeling@ POSTECH

  5. FEMLAB – modeling flow • Application areas • FEMLAB modeling flow • Acoustics • Bioscience • Chemical reactions • Diffusion • Electromagnetics • Fluid dynamics • Fuel cells and electrochemistry • Geophysics • Heat transfer • MEMS • Microwave engineering • Optics • Photonics • Porous media flow • Quantum mechanics • Radio-frequency components • Semiconductor devices • Structural mechanics • Transport phenomena • Wave propagation Plasma Application Modeling@ POSTECH

  6. Running of FEMLAB - Model Navigator When you run FEMLAB program, you meet Model Navigator from which you can choose Space dimension and pre-defined equations and modules. You can combine several modules using Multiphysics function. Click OK, then you can meet the interface to design the structures. Model Navigator Pre-defined equations Plasma Application Modeling@ POSTECH

  7. FEMLAB geometry and CAD environment 2-D Solver Zoom View mode Mesh generation Draw toolbar Plasma Application Modeling@ POSTECH In [Draw] menu, you also has the same toolbar buttons!

  8. FEMLAB geometry and CAD environment 3-D Plasma Application Modeling@ POSTECH

  9. FEMLAB geometry and CAD environment 2-D draw toolbar 3-D draw toolbar Plasma Application Modeling@ POSTECH

  10. 2-D geometry drawing (1) Open the Model Navigator and select 2D in the Space dimension list, then click OK Draw rectangle Draw triangle Create Composite Object Or Plasma Application Modeling@ POSTECH

  11. 2-D geometry drawing (2)   In [Option] menu  Plasma Application Modeling@ POSTECH

  12. 2-D geometry drawing (3) Plasma Application Modeling@ POSTECH

  13. 3-D geometry drawing (1) Open the Model Navigator and select 3D in the Space dimension list, then click OK. Go to the Draw menu and open the Work Plane Settings dialog box. Proceed to the Quick tab, select the x-y button, and then click OK. Plasma Application Modeling@ POSTECH

  14. 3-D geometry drawing (2)    Plasma Application Modeling@ POSTECH

  15. 3-D geometry drawing (3) In [Draw] menu Plasma Application Modeling@ POSTECH

  16. 3-D geometry drawing (4) Go to the Draw menu and choose Extrude. Select CO2 and enter 0.2 in the Distance field. Click OK. Click the Zoom Extents button to optimize your view of the new geometry object. Plasma Application Modeling@ POSTECH

  17. Generating mesh (1)    Plasma Application Modeling@ POSTECH

  18. Generating mesh (2)  Domain 1  Domain 2  Then, using mesh buttons ( ) , we can generate initial meshes and control the mesh density. Plasma Application Modeling@ POSTECH

  19. Generating mesh (3) Initialize Mesh Refine Mesh 1299 elements 5196 elements Refine Mesh (again) By default, the maximum element size used is 1/15 (in 2D) of the maximum axis parallel distance in the geometry. 20784 elements However, we can control element size and mesh density. Plasma Application Modeling@ POSTECH

  20. Generating mesh (4) Element number :15 Maximum element size scaling factor : 1 Element growth rate : 1.3 Element number :8 Maximum element size scaling factor : 2 Maximum element size scaling factor : 2 Element growth rate : 2 Element growth rate : 1.3 Plasma Application Modeling@ POSTECH

  21. Generating mesh (5) Mesh curvature factor : 0.3 The Mesh curvature factor determines the size of boundary elements compared to the curvature of the geometric boundary Mesh curvature cut off : 0.001 The Mesh curvature cut off prevents the generation of many elements around small curved parts of the geometry Mesh curvature factor : 0.3 Mesh curvature factor : 1 Mesh curvature cut off : 0.1 Mesh curvature cut off : 0.001 Plasma Application Modeling@ POSTECH

  22. Generating mesh (6) Plasma Application Modeling@ POSTECH

  23. Example 1 – model & structure Choose 2D, Electromagnetics, Electrostatics mode in Model Navigator At first, draw a rectangle and a small circle in the rectangle. Plasma Application Modeling@ POSTECH

  24. Example 1 – subdomain setting In Physics, Subdomain Setting menu, define the characteristics of each domain. To set the material properties, you can use Library material. In this example, let’s assume that subdomain 1 is air(=1) and subdomain 2 is silicon (~12). Plasma Application Modeling@ POSTECH

  25. Example 1 – boundary setting 100V 0V Plasma Application Modeling@ POSTECH

  26. Example 1 – mesh and solver Running solver Generating mesh Postprocess - potential Postprocess - potential Postprocess – electric field Plasma Application Modeling@ POSTECH

  27. Example 2 – 2D PDP model & structure 200V 0V  = 12  = 1  = 12 100V Plasma Application Modeling@ POSTECH

  28. Example 2 – 2D PDP mesh and postprocess Running solver Generating mesh Postprocess - potential Postprocess - potential Postprocess – electric field Plasma Application Modeling@ POSTECH

  29. Example 2 – 3D PDP Plasma Application Modeling@ POSTECH

  30. Example 3 – Spherical Capacitor (1)   Axial symmetry (2D) Electromagnetics Electrostatics Axes/Grid setting in [Options]   Draw the structure using circles, rectangle, and composite object function Define variables and expressions or values Plasma Application Modeling@ POSTECH

  31. Example 3 – Spherical Capacitor (2)  Set boundary conditions  Set subdomain 1 to Glass (quartz) material in Subdomain Setting.  Running solver Generating mesh Postprocess – electric potential Plasma Application Modeling@ POSTECH

  32. Example 3 – Spherical Capacitor Calculation of capacitance Postprocess – 3D plot C = 3.171097e-11 C = 3.170985e-11 Plasma Application Modeling@ POSTECH

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