TAGGED: rotation


October 29, 2024 at 1:04 pmMehdi BaghaeeSubscriber
Hi,
I am doing transient analysis of a plate modeled through solid elements. I need to know the ROTX, ROTY, ROTZ, of the whole nodes on one side of the plate in each time step. As you know the nodes of solid elements do not have ROTX, ROTY, ROTZ dofs, so how is it possible to get those parameters (ROTX, ROTY, ROTZ) in each time step?
Note that *VGET command does not work since the solid elements do not have ROTX, ROTY, and ROTZ degree of freedom.
Â
Â

October 29, 2024 at 4:03 pmDeepakAnsys Employee
Hi,
You can extract the rotational degree of freedom at nodes of the element using *VGET.
Regards,
Deepak K.

October 29, 2024 at 8:38 pmMehdi BaghaeeSubscriber
Â
I used *VGET command ( *VGET,RYt(1),NODE,1,ROT,Y ) to obtain ROTY of nodes, but as I said before, the *VGET command does not work and faced an error as below:
/BATCH Â
/input,menust,tmp,''
WPSTYLE,,,,,,,,0
/NOPR Â Â
KEYW,PR_SET,1 Â Â
KEYW,PR_STRUC,1Â
KEYW,PR_THERM,0Â
KEYW,PR_FLUID,0Â
KEYW,PR_ELMAG,0Â
KEYW,MAGNOD,0 Â Â
KEYW,MAGEDG,0 Â Â
KEYW,MAGHFE,0 Â Â
KEYW,MAGELC,0 Â Â
KEYW,PR_MULTI,0Â
/GOÂ
/PREP7 Â
ET,1,SOLID185 Â Â
MPTEMP,,,,,,,, Â
MPTEMP,1,0 Â
MPDATA,EX,1,,1e9
MPDATA,PRXY,1,,.3 Â Â
MPTEMP,,,,,,,, Â
MPTEMP,1,0 Â
MPDATA,DENS,1,,6700Â
BLOCK,0,10,0,10,0,1,
FLST,5,8,4,ORDE,2 Â Â
FITEM,5,1 Â Â
FITEM,5,8 Â
CM,_Y,LINE Â
LSEL, , , ,P51XÂ
CM,_Y1,LINEÂ
CMSEL,,_Y Â Â
LESIZE,_Y1, , ,10, , , , ,1Â
MSHAPE,0,3DÂ
MSHKEY,1
CM,_Y,VOLU Â
VSEL, , , , Â Â Â 1Â
CM,_Y1,VOLUÂ
CHKMSH,'VOLU' Â Â
CMSEL,S,_Y Â
VMESH,_Y1 Â Â
CMDELE,_Y Â Â
CMDELE,_Y1 Â
CMDELE,_Y2 Â
*dim,impulse,table,3
*SET,impulse(1,1),1,0 Â Â Â , Â 0 Â Â Â Â Â Â Â ! VALUES OF EXCITATION
*SET,impulse(1,0),0,22*timestup, Â 1 ! CORRESPONDING VALUES OF TIME Â
F, 177, FZ, %impulse% Â Â
WPSTYLE,,,,,,,,0
FLST,2,44,1,ORDE,12Â
FITEM,2,1 Â Â
FITEM,2,11Â
FITEM,2,122Â
FITEM,2,143Â
FITEM,2,153Â
FITEM,2,161
FITEM,2,243Â
FITEM,2,244
FITEM,2,267Â
FITEM,2,268
FITEM,2,287Â
FITEM,2,304
/GOÂ
D,P51X,ALL, , , , , , , , , , Â Â
ANTYPE,4
TRNOPT,FULLÂ
LUMPM,0Â
FINISH Â
/SOL
NSUBST,1000,0.01,0.001 Â
OUTRES,ERASE
OUTRES,ALL,ALL Â
TIME,1 Â
SOLVE Â Â
*GET, ARA,NODE,11,ROT,YÂÂ ROTY is not a valid degree of freedom for this solution. Â The DOF command may be used to add degrees of freedom. Â
Any other suggestion?
Â
Â
Â

October 30, 2024 at 1:31 pmdloomanAnsys Employee
You can create a remote point at locations where you want to know the rotation.Â The remote point is a node with rotational dof.Â It may help to later if you give the remote point pilot node and APDL name in the details.Â This "name" is an APDLÂ parameter with the value of the node number.

October 30, 2024 at 11:05 pmMehdi BaghaeeSubscriber
Thanks for your suggested method, by the way it is not clear to me how to relate the remote node with the one I want to calculate its rotation. Could you explain a little more or give a simple example?Â


October 30, 2024 at 3:43 pmmrifeAnsys Employee
Â
The *VFUN command has an option to transform a global x/y/z location to an local coordinate system location.Â So first create a local cylindrical coordinate system (where x/y/z are really r/theta/z) where theta is in the direction you want the rotation.Â Letâ€™s say this is CS 12.Â Now capture the origianal and deformed locations in an array:
(the following is from memory so it may not work...please review command help for each command)
/post1
set,last,last
*dim,node11,array,2,3,1
node11(1,1)=nx(11)
node11(2,1)=nx(11)+ux(11)
node11(1,2)=ny(11)
node11(2,2)=ny(11)+uy(11)
node11(1,3)=nz(11)
node11(2,3)=nz(11)+uz(11)
now do the transformation:
*vfun,local11,local,node11(1,1),12
Now the second column of local11 array will contain the theta values of node 11 in the original (as modeled) location and the deformed location.Â The difference is the rotation in degrees about the local CS z axis (in theta direction).Â Repeat for other local coordinate systems as needed.Â Â
mike
Â

October 30, 2024 at 11:33 pmMehdi BaghaeeSubscriber
Thanks for your suggested method. It seems great for small number of nodes, but since in my orginal problem, there are tons of nodes that their rotations must be at hand in each time step, the speed of simulation will decrease more because of do loops. Is it possible to apply your method in vector form? I mean put the positions of all nodes in an array and transform it to find the rotations.

October 30, 2024 at 11:41 pmmrifeAnsys Employee
Of course  see the help for *vget and *voper.Â To retrieve the same data (say x location) for all nodes at the same time.Â Then to operate on two vectors (like add them togther).
Â

October 30, 2024 at 11:59 pmMehdi BaghaeeSubscriber
but according to the Help, points to be transformed are specified in array having 3 consecutive columns of data, with the columns containing the x, y, and z global Cartesian coordinate locations, respectively, of the points. So it seems, *vfun usage is limited to one node.ðŸ¤¨

October 31, 2024 at 5:07 ammrifeAnsys Employee
And yet my example uses 2 rows....maybe try it yourself.

November 11, 2024 at 9:40 pmMehdi BaghaeeSubscriber
/BATCH Â
/input,menust,tmp,''
WPSTYLE,,,,,,,,0
/NOPR Â Â
KEYW,PR_SET,1 Â Â
KEYW,PR_STRUC,1Â
KEYW,PR_THERM,0Â
KEYW,PR_FLUID,0Â
KEYW,PR_ELMAG,0Â
KEYW,MAGNOD,0 Â Â
KEYW,MAGEDG,0 Â Â
KEYW,MAGHFE,0 Â Â
KEYW,MAGELC,0 Â Â
KEYW,PR_MULTI,0Â
/GOÂ
/PREP7 Â
ET,1,SOLID185 Â Â
MPTEMP,,,,,,,, Â
MPTEMP,1,0 Â
MPDATA,EX,1,,1e9
MPDATA,PRXY,1,,.3 Â Â
MPTEMP,,,,,,,, Â
MPTEMP,1,0 Â
MPDATA,DENS,1,,6700Â
BLOCK,0,10,0,10,0,1,
FLST,5,8,4,ORDE,2 Â Â
FITEM,5,1 Â Â
FITEM,5,8 Â
CM,_Y,LINE Â
LSEL, , , ,P51XÂ
CM,_Y1,LINEÂ
CMSEL,,_Y Â Â
LESIZE,_Y1, , ,10, , , , ,1Â
MSHAPE,0,3DÂ
MSHKEY,1
CM,_Y,VOLU Â
VSEL, , , , Â Â Â 1Â
CM,_Y1,VOLUÂ
CHKMSH,'VOLU' Â Â
CMSEL,S,_Y Â
VMESH,_Y1 Â Â
CMDELE,_Y Â Â
CMDELE,_Y1 Â
CMDELE,_Y2 Â
*dim,impulse,table,3
*SET,impulse(1,1),1,0 Â Â Â , Â 0 Â Â Â Â Â Â Â ! VALUES OF EXCITATION
*SET,impulse(1,0),0,22*timestup, Â 1 ! CORRESPONDING VALUES OF TIME Â
F, 177, FZ, %impulse% Â Â
WPSTYLE,,,,,,,,0
FLST,2,44,1,ORDE,12Â
FITEM,2,1 Â Â
FITEM,2,11Â
FITEM,2,122Â
FITEM,2,143Â
FITEM,2,153Â
FITEM,2,161
FITEM,2,243Â
FITEM,2,244
FITEM,2,267Â
FITEM,2,268
FITEM,2,287Â
FITEM,2,304
/GOÂ
D,P51X,ALL, , , , , , , , , , Â Â
ANTYPE,4
TRNOPT,FULLÂ
LUMPM,0Â
FINISH Â
/SOL
NSUBST,1000,0.01,0.001 Â
OUTRES,ERASE
OUTRES,ALL,ALL Â
TIME,1 Â
SOLVE Â Â
/post1
set,last,last
*dim,node11,array,2,3,1
node11(1,1)=nx(11)
node11(2,1)=nx(11)+ux(11)
node11(1,2)=ny(11)
node11(2,2)=ny(11)+uy(11)
node11(1,3)=nz(11)
node11(2,3)=nz(11)+uz(11)
*vfun,local11,local,node11(1,1),12faced error!



October 30, 2024 at 10:53 pmMehdi BaghaeeSubscriber
Â
Â

October 31, 2024 at 2:26 pmdloomanAnsys Employee
The remote point would be a new node at the same location as the node you were trying to obtain the rotation of.Â It does probably require you to imprint a face in the geometry at the location of interest, so may not be practical in your case.Â If the locations of interest are on the surface you could mesh the surface with very thin shell elements, which do have rotational dof.

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