s.s. yang and j.k. lee femlab and its applications postec h plasma application modeling lab. oct....
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S.S. Yang and J.K. Lee
FEMLAB and its applications
POSTECH
Plasma Application Modeling Lab.
Oct. 25, 2005
Plasma ApplicationModeling @ POSTECH
Contents
Introduction of FEMLABHow 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
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FEMLAB (COMSOL Multiphysics)
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”
COMSOL Multiphysics
Ver. 3.2
1995 1999 2000 2001 2002 2003 2004 2005
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).
(Package name is changed)
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FEMLAB - Key featuresFast, 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
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FEMLAB – modeling flow Application areas• 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
FEMLAB modeling flow
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Running of FEMLAB - Model Navigator
Model Navigator Pre-defined equations
When you run FEMLAB program, you meet Model Navigator from which you can choose Space dimension and pre-defined equations and modules.
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.
You can combine several modules using Multiphysics function. Click OK, then you can meet the interface to design the structures.
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Draw toolbar
Mesh generation
Solver Zoom View mode
FEMLAB geometry and CAD environment
2-D
In [Draw] menu, you also has the same toolbar buttons!
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FEMLAB geometry and CAD environment
2-D draw toolbar
3-D draw toolbar
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Create Composite Object
2-D geometry drawing (1)
Or
Draw rectangle Draw triangle
Open the Model Navigator and select 2D in the Space dimension list, then click OK
Open the Model Navigator and select 2D in the Space dimension list, then click OK
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Open the Model Navigator and select 3D in the Space dimension list, then click OK.
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.
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.
3-D geometry drawing (1)
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Go to the Draw menu and choose Extrude. Select CO2 and enter 0.2 in the Distance field. Click OK.
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.
Click the Zoom Extents button to optimize your view of the new geometry object.
3-D geometry drawing (4)
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Then, using mesh buttons ( ) ,we can generate initial meshes and control the mesh density.
Generating mesh (2)
Domain 1
Domain 2
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1299 elements 5196 elements
20784 elements
Initialize Mesh Refine Mesh
Refine Mesh (again)By default, the maximum element size used is 1/15 (in 2D) of the maximum axis parallel distance in the geometry.
However, we can control element size and mesh density.
Generating mesh (3)
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Maximum element size scaling factor : 1Element growth rate : 1.3
Maximum element size scaling factor : 2Element growth rate : 1.3
Maximum element size scaling factor : 2Element growth rate : 2
Element number :15
Element number :8
Generating mesh (4)
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The Mesh curvature factor determines the size of boundary elements compared to the curvature of the geometric boundary
The Mesh curvature factor determines the size of boundary elements compared to the curvature of the geometric boundary
The Mesh curvature cut off prevents the generation of many elements around small curved parts of the geometry
The Mesh curvature cut off prevents the generation of many elements around small curved parts of the geometry
Mesh curvature factor : 0.3Mesh curvature cut off : 0.001
Mesh curvature factor : 1Mesh curvature cut off : 0.001
Mesh curvature factor : 0.3Mesh curvature cut off : 0.1
Generating mesh (5)
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Example 1 – model & structure
Choose 2D, Electromagnetics, Electrostatics mode in Model Navigator
Choose 2D, Electromagnetics, Electrostatics mode in Model Navigator
At first, draw a rectangle and a small circle in the rectangle.
At first, draw a rectangle and a small circle in the rectangle.
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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).
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).
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Example 1 – mesh and solver
Generating mesh
Postprocess - potential Postprocess – electric field
Postprocess - potential
Runningsolver
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Example 2 – 2D PDP model & structure
200V 0V
100V
= 1
= 12
= 12
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Generating mesh
Postprocess - potential Postprocess – electric field
Postprocess - potential
Runningsolver
Example 2 – 2D PDP mesh and postprocess
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Example 3 – Spherical Capacitor (1)
Axial symmetry (2D) Electromagnetics Electrostatics Axes/Grid setting in [Options]
Define variables and expressions or values
Draw the structure using circles, rectangle, and composite object function
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Example 3 – Spherical Capacitor (2)
Set boundary conditions
Set subdomain 1 to Glass (quartz) material in Subdomain Setting.
Generating mesh Postprocess – electric potential
Runningsolver
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