Re: [femm] *.ans file format

[David Meeker <dmeeker@xxxxxxxxxxxxxxxxx>]

marki denaro wrote:

> Dear the Femm expert
> I am student fromm Institute of Technology of Sepuluh
> Nopemeber (ITS)at Surabaya-Indonesia
>
> I'm interested to use your femm software, and I have
> been try to use your software to detect the leakage
> flux of 3phasa induction motor. And result of this
> simulation is satisfied enough.
>
> Now I have been build a software to combine the Finite
> element method with The Neural Network Method.
>
> and for the Finite element method, I want to spawn
> your program, for this I need your explanation about:
> the meaning of data in *.ans file

Everything before the line that says: "[Solution]" is just a copy of the
input .fem file. I probably should detail the input file as well, but I
don't have the time this morning. The input files are also somewhat
human-readable.

Next line is the number of nodes in the mesh. Then follows a list of nodal
values for the solution. If frequency is greater than zero, there are 4
columns:
1) Node's x (or r) coordinate
2) Node's y (or z) coordinate
3) Real component of the nodal value of A or Phi
4) Imaginary component of the nodal value of A or Phi
If the frequency is equal to zero, there are just three columns:
1) Node's x (or r) coordinate
2) Node's y (or z) coordinate
3) Nodal value of A or Phi
Note that if the problem is 2-D planar, the nodal values are A, the magnetic
vector potential. If the problem is axisymmetric, the nodal values are Phi,
which is equal to 2*Pi*r*A, where r is the r location of that node.

After the list of nodes comes the elements. First, there is a line
containing the number of elements in the solution. Then, there is a line for
each element containing element data. If the frequency is equal to zero, the
element data contains 6 columns:
1,2,3) Numbers of the nodes that form the element, listed in a
counter-clockwise order
4) Block label number that defines the element's material properties
5) x- or r-direction permeability of the element
6) y- or z-direction permeability of the element
If the frequency is greater than zero, columns 5 and 6 are omitted. In both
cases, note that the block label number corresponds to the order in which the
block labels are listed in the input file, e.g. block label 0 would
correspond to the first block label.

Then comes the "circuit" data. First, there is an entry denoting the number
of circuit properties. Then, there is a
line for each circuit property. If the frequency is zero, there are two
columns. The first column a "circuit type" indicator, where 0 indicates a
voltage and a nonzero value a current density. The second column is then
either the resulting voltage or current density, depending upon the
type flag. If the frequency is non-zero, there is an additional column so
that both the real and imaginary components of the voltage or current density
can be represented.

Also refer to the OnOpenDocument subroutine in the femmviewdoc.cpp file of
the femmview source code to see the file loading is actually implemented.

Note that the femme preprocessor does some sort of vital things as far as
"premeshing" the geometry. It writes the .poly file that triangle needs to
do the meshing. If you want to spawn an entire analysis independently,
you'll probably need some code to do this premeshing. For the 2.1a version,
I did at one point write a stripped down command line version of the
preprocessor that just had what code it takes to do the OnOpenDocument
function and the premeshing function OnWritePoly. I suppose that would be
relatively easy to reproduce for the 3.0 version as well.

Dave Meeker



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