The following examples are available:
This section shows you how to perform a sample 3D static magnetic analysis.
This example calculates the force acting on the armature when the coil in the solenoid actuator shown in Figure 5.4: Solenoid Actuator is energized . A static (DC) current excites the coil and provides the force to move the armature. The current is 6 amps and there are 500 turns in the coil. The analysis uses a 1/4 symmetry model of the positive x and y quadrant.
The analysis uses a relative permeability of 1.0 for the air regions.
The B-H data for the pole and armature steel follows. You will enter the B and H values in this analysis.
| H(A/m) | B(T) | H(A/m) | B(T) |
|---|---|---|---|
| 355 | 0.70 | 7650 | 1.75 |
| 405 | 0.80 | 10100 | 1.80 |
| 470 | 0.90 | 13000 | 1.85 |
| 555 | 1.00 | 15900 | 1.90 |
| 673 | 1.10 | 21100 | 1.95 |
| 836 | 1.20 | 26300 | 2.00 |
| 1065 | 1.30 | 32900 | 2.05 |
| 1220 | 1.35 | 42700 | 2.10 |
| 1420 | 1.40 | 61700 | 2.15 |
| 1720 | 1.45 | 84300 | 2.20 |
| 2130 | 1.50 | 110000 | 2.25 |
| 2670 | 1.55 | 135000 | 2.30 |
| 3480 | 1.60 | 200000 | 2.41 |
| 4500 | 1.65 | 400000 | 2.69 |
| 5950 | 1.70 | 800000 | 3.22 |
The analysis uses a smart sizing level (LVL) of 8. For production work a finer mesh should be used (LVL 6).
All surfaces are assumed to be flux-parallel. This is a natural boundary condition that is satisfied automatically without any prescription of an explicit boundary condition.
A single node is constrained to avoid an ill-conditioned problem.
This example uses a smart element sizing (SmartSizing) level of 8.
The computed results you should obtain are:
| Virtual Work Force (z direction) = -12.77 N |
| Maxwell Force (z direction) = -11.87 N |
The total force acting on the armature can be computed by multiplying the results above by a factor of 4 for symmetry. Forces in the x and y directions cancel.
For additional information on the solution to this problem, see M. Gyimesi and D. Ostergaard, "Non-Conforming Hexahedral Edge Elements for Magnetic Analysis," IEEE Transactions on Magnetics, Vol. 34, No. 5 (1998).
/prep7 /title, 3D Static Force Problem - Tetrahedral /com, ! ! define analysis parameters ! n=500 ! coil turns i=6 ! current per turn ! !define element type ! et,1,96 ! mp,murx,1,1 !define material properties for air and steel tb,bh,2,,40 tbpt,,355,.7 ,,405,.8 ,,470,.9 ,,555,1.0 ,,673,1.1 ,,836,1.2 ,,1065,1.3 ,,1220,1.35 ,,1420,1.4 ,,1720,1.45 ,,2130,1.5 ,,2670,1.55 ,,3480,1.6 ,,4500,1.65 ,,5950,1.7 ,,7650,1.75 ,,10100,1.8 ,,13000,1.85 ,,15900,1.9 ,,21100,1.95 ,,26300,2.0 ,,32900,2.05 ,,42700,2.1 ,,61700,2.15 ,,84300,2.2 ,,110000,2.25 ,,135000,2.3 ,,200000,2.41 ,,400000,2.69 ,,800000,3.22 tbcopy,bh,2,3 ! /pnum,volu !create pole volumes block,0,63.5,0,25/2,0,25 /view,1,1,1,1 /replot block,38.5,63.5,0,25/2,25,125 block,13.5,63.5,0,25/2,125,150 vglue,all ! !create armature and air volumes and compress numbers ! block,0,12.5,0,5,26.5,125 ! armature block,0,13,0,5.5,26,125.5 ! air region vovlap,1,2 numcmp,volu cyl4,,,0,0,100,90,175 vovlap,all numcmp,volu ! !set volume attributes ! vsel,s,volu,,1 vatt,3,1,1 ! armature vsel,s,volu,,3,5 vatt,2,1,1 ! pole ! !mesh the model ! allsel,all smrt,8 ! for production work a finer mesh should be used, (LVL 6) mshape,1,3d mshkey,0 vmesh,all /pnum,mat,1 /number,1 eplot ! !define armature as a component and apply force flags ! esel,s,mat,,3 ! armature cm,arm,elem cmsel,,arm nsle bf,all,mvdi,1 ! apply virtual work flags to the armature nsel,r,ext esln cmsel,u,arm sf,all,mxwf ! apply maxwell surface flags to the air surrounding the armature ! !scale the model to meters ! allsel,all vlscale,all,,,.001,.001,.001,,0,1 ! !create the coil ! local,12,0,0,0,75/1000 wpcsys,-1 race,.0285,.0285,.014,n*i,.018,.0966,,,'coil1' /eshape,1 eplot save finish ! /solu d,2,mag,0 ! apply boundary conditions ! allsel,all magsolv,3,,,,,1 ! solve finish ! /post1 ! calculate the armature forces ! cmsel,,arm ! select the elements at the air/armature interface nsel,,ext esln etab,fmx_x,fmag,x ! store maxwell forces etab,fmx_y,fmag,y etab,fmx_z,fmag,z etab,fvw_x,nmisc,4 ! store virtual work forces etab,fvw_y,nmisc,5 etab,fvw_z,nmisc,6 ssum ! sum the forces over all the selected elements ! finish
Another Ansys, Inc. publication, the Mechanical APDL Verification Manual, contains other examples of various types of analyses, including the following examples of 3D static magnetic analysis: