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APDL Maxwell Stress Tensor force very small

APDL Maxwell Stress Tensor force very small

APDL Maxwell Stress Tensor force very small

(OP)
I'm currently trying to simulate a magnetically levitating platform as part of a university project. Simplifying the problem and modelling it in 2D dimensions worked well and the results seemed logical. However now I've moved onto attempting to simulate it in 3D the force I'm seeing on the magnets seem way too small. So as a test I checked the force that two magnets exert on each other at a gap of 3mm and saw that the forces were once again very small, 10^-15N. However the magnetic field strength matches what the data sheet for the magnet said it should be.

Here is my code, what have I done wrong?:
/prep7
BLOCK,-6.350000e+00,6.350000e+00,-1.500000e+00,-2.690000e+01,-3.175000e+00,3.175000e+00
BLOCK,-6.350000e+00,6.350000e+00,1.500000e+00,2.690000e+01,-3.175000e+00,3.175000e+00
BLOCK,-2.540000e+01,2.540000e+01,-5.080000e+01,5.080000e+01,-1.270000e+01,1.270000e+01
/VIEW,1,1,1,1
/ANG,1
/REP,FAST
FLST,2,1,6,ORDE,1
FITEM,2,3
FLST,3,2,6,ORDE,2
FITEM,3,1
FITEM,3,-2
!*
VSBV,P51X,P51X, , ,KEEP
FLST,2,3,6,ORDE,3
FITEM,2,1
FITEM,2,-2
FITEM,2,4
VGLUE,P51X
!*
!*
/NOPR
KEYW,PR_SET,1
KEYW,PR_STRUC,0
KEYW,PR_THERM,0
KEYW,PR_FLUID,0
KEYW,PR_ELMAG,1
KEYW,MAGNOD,0
KEYW,MAGEDG,1
KEYW,MAGHFE,0
KEYW,MAGELC,0
KEYW,PR_MULTI,0
KEYW,PR_CFD,0
/GO
!*
/COM,
/COM,Preferences for GUI filtering have been set to display:
/COM, Magnetic-Edge
!*
!*
ET,1,SOLID236
!*
!*
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,MURX,1,,1
MPDATA,MURY,1,,1
MPDATA,MURZ,1,,1
*CSET,1,2, 1,2,
MPCOPY, ,1,2
TBCOPY,ALL,1,2
!*
*CSET,1,2, 1,3,
MPCOPY, ,1,3
TBCOPY,ALL,1,3
!*
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,MGXX,2,,
MPDATA,MGYY,2,,9.91E5
MPDATA,MGZZ,2,,
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,MGXX,3,,
MPDATA,MGYY,3,,-9.91E5
MPDATA,MGZZ,3,,
CM,_Y,VOLU
VSEL, , , , 2
CM,_Y1,VOLU
CMSEL,S,_Y
!*
CMSEL,S,_Y1
VATT, 3, , 1, 0
CMSEL,S,_Y
CMDELE,_Y
CMDELE,_Y1
!*
CM,_Y,VOLU
VSEL, , , , 1
CM,_Y1,VOLU
CMSEL,S,_Y
!*
CMSEL,S,_Y1
VATT, 2, , 1, 0
CMSEL,S,_Y
CMDELE,_Y
CMDELE,_Y1
!*
CM,_Y,VOLU
VSEL, , , , 4
CM,_Y1,VOLU
CMSEL,S,_Y
!*
CMSEL,S,_Y1
VATT, 1, , 1, 0
CMSEL,S,_Y
CMDELE,_Y
CMDELE,_Y1
!*
SMRT,6
MSHAPE,1,3D
MSHKEY,0
!*
FLST,5,3,6,ORDE,3
FITEM,5,1
FITEM,5,-2
FITEM,5,4
CM,_Y,VOLU
VSEL, , , ,P51X
CM,_Y1,VOLU
CHKMSH,'VOLU'
CMSEL,S,_Y
!*
VMESH,_Y1
!*
CMDELE,_Y
CMDELE,_Y1
CMDELE,_Y2
!*
SMRT,3
FLST,5,3,6,ORDE,3
FITEM,5,1
FITEM,5,-2
FITEM,5,4
CM,_Y,VOLU
VSEL, , , ,P51X
CM,_Y1,VOLU
CHKMSH,'VOLU'
CMSEL,S,_Y
!*
!*
VCLEAR,_Y1
VMESH,_Y1
!*
CMDELE,_Y
CMDELE,_Y1
CMDELE,_Y2
!*
FLST,2,3,6,ORDE,3
FITEM,2,1
FITEM,2,-2
FITEM,2,4
VLSCAL,P51X, , ,0.001,0.001,0.001, ,0,1
ESEL,S,MAT,,2
CM,MAG1,ELEM
/UI,MESH,OFF
ESEL,S,MAT,,3
CM,MAG2,ELEM
!*
!*
FMAGBC,'MAG1','MAG2'
ALLSEL,ALL
FINISH
/SOL
/STATUS,SOLU
SOLVE
FINISH
/POST1
FMAGSUM,'MAG1','MAG2'

I understand that using the GUI is probably not the best way to tackle the problem but I have been chucked in at the deep end with this project, having no previous experience with Ansys. Any help would be greatly appreciated.

Thanks
Benji

RE: APDL Maxwell Stress Tensor force very small

What version of Maxwell and ANSYS are you working with?

I ask because you may not actually have an error in your work, but it could be something that has been corrected in an updated version of Maxwell. If you have an active license, you should have ANSYS 14.5.7 and Maxwell 16.0.3. ANSYS itself is fine, but the newer family members such as Maxwell have had a number of bug updates and patches in recent builds.

Hopefully something that simple may fix your problem. :) Otherwise we can take it from there!

~ Kherszal

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