This document is based on the "Introduction to FEA with FEMM" tutorial by Ian Stokes-Rees, TSS (UK) Ltd.
Many thanks to Kostadin Brandisky of the TechnicalUniversity of Sofia for developing the example problems used in this tutorial.
2 1.5 1 0.5 0 -0.5 -1 -1.5 -2 -2 0 2
Figure 1: Square Cross-Section Capacitor Because of the symmetry, only one quarter of the device need be modeled. The finished model will look as pictured below in Figure 2 when ready for analysis.
Figure 2: Completed example in the electrostatics preprocessor.
Thesteps required to create this model are as follows: 2.1 Create model Start FEMM by select the "femm 4.0" entry placed in the "femm 4.0" section of your start menu. After the program starts, "File|New" from the main menu. Select "Electrostatics Problem" in the "Create a new problem" dialog that appears. After you hit "OK", a blank electrostatics problem will appear. Select “nodes” from the tool bar(this is the farthest button on the left with a small black box: ) and place 6 nodes for the corner of a box (at, for example, (0,1), (1,1), (1,0) ,(2,0),(2,2) and (0,2)). One can place nodes either by moving the mouse pointer to the desired location and pressing the left mouse button, or by pressing the key and manually entering the point coordinates via a popup dialog. Select “lines” from thetool bar (second button from the left with a blue line: ). To select a node to be the endpoint of a line, click near each desired endpoint with the left mouse button. Select connect the points as pictured in Figure 2 using this mouse endpoint selection approach. 2.2 Add materials to the model Select “Properties|Materials” off of the main menu. In the dialog that appears, click the “Add Material”button. A dialog will pop up with edit boxes for the various material properties. Change the name of the property from “New Material” to “air.” By default the permittivity of a new material is 1, which is what we require for air. Press the “OK” button to complete the creation of the material. 2.3 Define materials for each region ), and place a block label Now click on “Block Labels” (the tool bar...