How to use mor4ansys in windows

[sertac]

Hi,

I am a mechanical engineer and I do not have so much information about
programming. I only want to run mor4ansys in WindowsXP environment and
obtaine mass stiffness and damping matrices to use them in MATLAB. VCan
anybody discribe me to use mor4ansys basically and obtaining the system
matrices.

Thank you very very much.

Best Regards,

Sertaç

[Evgenii Rudnyi]

> I am a mechanical engineer and I do not have so much information about
> programming. I only want to run mor4ansys in WindowsXP environment and
> obtaine mass stiffness and damping matrices to use them in MATLAB. VCan
> anybody discribe me to use mor4ansys basically and obtaining the system
> matrices.

Dear Sertac,

mor4ansys is a command-line tool and the main potential problem for
Windows users is to learn cmd - a Windows shell.

1) Starting the command line shell:

You can find the icon Command Prompt in Accessory or simply make Start
| Run | type in "cmd" | Click OK

There are many things to learn but the most important are described
below

2) Changing directory. You have to make the directory with the files as
the current directory.

cd path

There is a trick. If you type in "cd " and then drag the directory from
Explorer to cmd, you will have the full path typed in automatically.

dir

will show you the file in the current directory. If you do not see the
right files, try again.

3) Running a program. Program should be in the current directory or on
the path. You can set up your path somewhere in Control Panel | System.

Try type in

mor4ansys

If everything is correct, you should see output with mor4ansys options.
If you see "A command not found", check your path or copy mor4ansys in
the current directory.

4) Where to find more info:

Type help in cmd or search in Windows Help (Start | Help).

Well, I should say that it is not too difficult but it can take some
time at the beginning. Sorry for inconvenience.

Evgenii

[Colm Mc Sweeney]

Hi Sertac
if your only objective is just to read ANSYS produced system matrices
into matlab sparse format
you can do this without using mor4ansys

ANSYS allows you to write out system matrices in harwell boeing format,
make sure you have a <jobname>.full file by
running (see Evgenii's thruster example)
resume
/solu
allse
antype,static
eqslv,sparse
nsubst,1
wrfull,1
ematwrite,yes
solve
fini

then dump the matrices
/aux2
file ,<jobname>,full,
hbmat ,,,,ascii,stiff,yes/no
or
hbmat ,,,,ascii,mass,yes/no
or
hbmat ,,,,ascii,damp,yes/no

these text files can be read into MATLAB using software from
http://math.nist.gov/MatrixMarket/
or
http://www.csit.fsu.edu/%7Eburkardt/m_src/hb_to_msm/hb_to_msm.html

or you could convert the harwell boeing to market format using MTL
before reading the matrices in.

i can forward on C code if you want to do this

regards,
Colm.

[Evgenii Rudnyi]

Dear Colm,

Thank you for your information. We should not forget about HBMAT
indeed. I would like to share my experience with this.

Well, I use HBMAT to debug mor4ansys. I should say that there is still
a small bug in mor4ansys concerning models with a CE family of
commands. When there are hundreds CE constraints, then mor4ansys is
doing well, but when there are thousands CE constraints, the results
from mor4ansys are not that good. Unfortunately, I have not found this
bug yet. In this case, it seems that now HBMAT is the only option to
proceed. Note that this does not concern Dirichlet constraints.

Yet, there are some problems with FULL file. Well, HBMAT just dumps its
content.

1) The ordering of matrices is not natural. In the FULL file, there is
a special record with a nodal equivalence table. Anybody knows if this
is written in the Harwell-Boeing format? With mor4ansys you can learn
ordering from matrix C (see matrix.C.names).

2) It is not straightforward to have all the matrices.

After static analysis, there is a stiffness matrix only (your example
will not work).

After transient and harmonic analyses, there is a single matrix as
well. It is a combination of all the matrices needed to solve a system
of linear equations. After harmonic analysis, the matrix is complex.

Modal analysis seems to produce all the matrices indeed. Yet, it is
unclear how to do it for the first order problems.

This was the reason why I have left both FULL and EMAT files to read
the matrices.



It would be good if someone spent some more time to document what ANSYS
writes in FULL file after different analyses. It would be nice to use
only the FULL file to read all the matrices.

Best wishes,

Evgenii

[sertac]

Hello again,

By now, I have the system matrices and I could use them in MATLAB. If I
would have further questions about the matrices or if there will be a
problem, I will contact to you.

Thank you very much.

Best Regards,

Sertac

[sertac]

Dear Evgenii and Colm,

Evgenii, I tried to reduce the order of a 10 DOFs sample system using
mor4ansys. I used the command

mor4ansys filename.full filename.emat -f -w matrices -N 5

but the program gave an output of 10 DOFs again instead of 5 DOFs. Is
there a problem or am I doing something wrong?

Colm, Can you send me the C code?

Thank you and regards,

Sertaç