Obtaining mass and stiffness matrices in cylindrical coordinates
Obtaining mass and stiffness matrices in cylindrical coordinates
(OP)
Hello,
I am using Ansys to study a cyclic symmetric structure. But I just use it to obtain the mass and stiffness matrices of an elementary sector.
In order to make the analyze of the matrices easier, I need to obtain them in global cylindrical coordinates. It is why I have a problem.
After importing my FE model in Ansys (the elementary sector), I use the commands :
- CSYS,1 to work in cylindrical coordinates
- EMATWRITE, YES
- WRFULL to get the files containing the mass and stiffness matrices.
However, this seems unefficient because I get the matrices in global cartesian coordinates.
Would anyone know which command is required beside of "CSYS,1" to be sure to obtain the matrices in global cylindrical coordinates ?
Thank you.
Alain
I am using Ansys to study a cyclic symmetric structure. But I just use it to obtain the mass and stiffness matrices of an elementary sector.
In order to make the analyze of the matrices easier, I need to obtain them in global cylindrical coordinates. It is why I have a problem.
After importing my FE model in Ansys (the elementary sector), I use the commands :
- CSYS,1 to work in cylindrical coordinates
- EMATWRITE, YES
- WRFULL to get the files containing the mass and stiffness matrices.
However, this seems unefficient because I get the matrices in global cartesian coordinates.
Would anyone know which command is required beside of "CSYS,1" to be sure to obtain the matrices in global cylindrical coordinates ?
Thank you.
Alain





RE: Obtaining mass and stiffness matrices in cylindrical coordinates
I don't know if what you want is even possible in Ansys. It it is possible, then csys,1 would not have any effect anyway.
RSYS,1 on the other hand could have a chance to do, what you would like to do.
Regards,
Alex
RE: Obtaining mass and stiffness matrices in cylindrical coordinates
sometimes it's the "DSYS" command which governs the listings of coordinates. If the suggestion of the "RSYS" doesn't work, I'd have a try with DSYS.
RE: Obtaining mass and stiffness matrices in cylindrical coordinates
I tried RSYS,1 and DSYS,1 none of them seems to give waht I am looking for ... I know this is possible to do with Ansys because I did it already with another structure that was imported from Nastran.
In order to knoe where could the problem be from I edited the .db files of the previous structure and the one i am studying now, the only differences (beside of the structures data) are in :
Record 2 -> 5th position ("1" instead of "0")
Record 7 -> 61st position ("6" instead of "-1")
I tried to look in the Ansys Interface Guide but I couldn't find the meaning of these records in an input "db" file ...
Thank you for your help.
Alain
RE: Obtaining mass and stiffness matrices in cylindrical coordinates
To rotate the nodes:
CSYS,11
NROTAT,all
To change element's coordinate system:
EMODIF,...
Regards
RE: Obtaining mass and stiffness matrices in cylindrical coordinates
CSYS, 1
and then
NROTAT, ALL
can make what I was looking for !
Alain
RE: Obtaining mass and stiffness matrices in cylindrical coordinates
glad it works!...
Regards