Copyright © 1999 Institute of Electrical and Electronics Engineers.
Reprinted from IEEE Spectrum (December 1999, Volume 36- Number 12)
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Quick and easy field analysis
Kenneth R. Foster
Engineers who need to model electromagnetic fields frequently turn to finite-element analysis (FEA), a numerical technique for solving field problems of all kinds. QuickField is a slick FEA for solving two-dimensional field problems. Developed by Tor Cooperative, a Russian firm, the program is marketed outside Russia by Tera Analysis. It first appeared in an MS-DOS version (under the name Elcut) early in the 1990s [Spectrum, December 1993, p.64]. This latest release, Version 4.2, is a native application for Windows 95/98/NT.
QuickField consists of several modules, called by the main program as necessary. The user defines the geometry of the problem, labels the blocks, edges, and vertices, and enters information about boundary conditions and material properties using a simple drawing module. The program then calls modules to generate the mesh (used in the finite-element analysis) and solves the problem. Finally, the user visualizes the results and calculates quantities such as fluxes through surfaces or line integrals of field components using the postprocessor module.
Depending on the options purchased by the user, QuickField can solve a wide variety of 2-D problems, or 3-D problems with axial symmetry. These include dc or ac magnetics, electrostatics, current flow, heat analysis, and stress analysis problems. Material properties may be nonlinear or anisotropic. The sidebar illustration, for example, shows the computed magnetic field in an iron structure characterized by a nonlinear flux density versus magnetic field curve.
QuickField can handle many coupled field problems as well. For instance, the user can determine the current pattern in a conductor and then the temperature increase that results when it is exposed to flowing air.
Compared to other FEA programs, QuickField has two main virtues: exceptional user-friendliness and blinding speed. The program has a typical Windows interface, drop-down menus, and extensive help facility, and is equipped with many sample programs. While the user has to understand something about the physics of the problem to successfully carry out a simulation, the mechanics themselves are straightforward. Even on a slow PC, users can construct and run models with tens of thousands of nodes, which makes it practical to solve very complex models on modest platforms. The program itself is small, a few megabytes with various required files.
I loaded my copy of QuickField onto my slow (100-MHz) Toshiba laptop. While on travel last summer, I developed and ran QuickField simulations, in one case verifying the results of an elaborate theoretical calculation in a paper I was reviewing.
QuickField has limitations, of course. As with most prepackaged FEA programs, it can handle only standardized kinds of problems. Some of my work involves a nonstandard form of the heat equation, which cannot be accommodated by the program. Nor can QuickField handle transient analysis or electrical problems involving both electrostatics and current flow (that is, both capacitance and conductance at once).
By comparison PDEase, another FEA program for personal PCs [Spectrum, October 1994, p. 74] is slower but more flexible, since it is not limited to particular equations. For full 3-D simulations, users would need to use another program, most likely on a workstation.
All things said, QuickField is an outstanding program that opens up the possibility of doing 2-D electromagnetic (and other field) simulations on modest personal computers. For problems within its range, QuickField is the way to go. Cost ranges from €1000 to €8000, depending on the configuration.
QuickField Version 4.2. Finite-element analysis software for simulation of electromagnetic, thermal, and stress problems. Runs on Win 95/98/NT. Minimum memory requirement 8MB, recommended 32MB. A limited time demo and limited student versions may be downloaded from the company's Web site. The program, with accessory files, takes up approximately 3 MB of hard-disk space.
Kenneth R. Foster (F) is a professor in the department of bioengineering at the University of Pennsylvania, in Philadelphia. He is immediate past president of the IEEE Society for Social Implications of Technology.