The following examples are available:
The following example shows how to perform a 2D transient magnetic analysis of a solenoid actuator.
The analysis, based on a solenoid actuator, analyzes the actuator as a 2D axisymmetric model. The example calculates the force on the armature (the moving component of the actuator), inductance of the coil, and the coil current in response to a voltage excitation. Figure 4.2: Diagram of a Solenoid Actuator below shows you the solenoid actuator:
The analysis uses the parameters listed below to model the actuator geometry:
Parameter | Description |
---|---|
n = 650 | Number of turns in the coil; used in postprocessing |
ta = .75 | Thickness of inner leg of magnetic circuit |
tb = .75 | Thickness of lower leg of magnetic circuit |
tc = .50 | Thickness of outer leg of magnetic circuit |
td = .75 | Armature thickness |
wc = 1 | Width of coil |
hc = 2 | Height of coil |
gap = .25 | Gap |
space = .25 | Space around coil |
ws = wc+2*space | |
hs = hc+.75 | |
w = ta+ws+tc | Total width of model |
hb = tb+hs | |
h = hb+gap+td | Total height of model |
acoil = wc*hc | Coil area |
The solenoid actuator model for this transient example is identical to the solenoid example described in 2D Static Magnetic Analysis. Instead of a DC current excitation, the coil is supplied a voltage excitation which varies over time.
The coil is supplied a voltage which ramps from 0 volts to 12 volts over a .01 second time frame. After that, the voltage is held constant and the analysis runs until a time of .06 seconds. The coil requires additional characterization, including cross-section area and fill factor. Resistivity for copper is also provided. The armature is assumed to be solid steel, so it requires the input of electrical resistivity as well.
The purpose of the example analysis is to calculate the coil current, armature force, and coil inductance over time in response to the applied voltage excitation.
The solution uses constant time stepping over three load steps ending at .01, .03, and .06 seconds respectively.
You can perform the example analysis of transient eddy currents using the commands shown below. Any text prefaced by an exclamation point (!) is a comment.
/PREP7 /TITLE, 2D Solenoid Actuator Transient Analysis /NOPR ET,1,PLANE233,,,1 ! Define element type, set for axisymmetric run ET,2,PLANE233,2,,1 ! Axisymmetric, coil option MP,MURX,1,1 ! Define material permeability (air) MP,MURX,2,1000 ! Permeability (backiron) MP,MURX,3,1 ! Permeability (coil) MP,MURX,4,2000 ! Permeability (armature) MP,RSVX,3,3e-8 ! Define coil resistivity MP,RSVX,4,70e-8 ! Define armature resistivity /com ! Set parameter values n=650 ta=.75 tb=.75 tc=.50 td=.75 wc=1 hc=2 gap=.25 space=.25 ws=wc+2*space hs=hc+.75 w=ta+ws+tc hb=tb+hs h=hb+gap+td acoil=wc*hc ! Cross-section of coil (cm**2) Sc=acoil*.01**2 ! coil cross-sectional area pi=acos(-1) Ri=(ta+space)*0.01 ! inner radius Ro=(ta+space+wc)*0.01 ! outer radius Rm=(Ri+Ro)/2 ! mean radius Vc=pi*(Ro**2-Ri**2)*(hc*0.01) ! coil volume Rc=3e-8*(n/Sc)**2*(Vc/0.95) ! coil resistance R,1,,Sc,n,Rm,1,Rc ! Coil constants (thick, scaled area, turns, mean rad, dir., resistance) /PNUM,AREA,1 RECTNG,0,w,0,tb ! Create rectangular areas RECTNG,0,w,tb,hb RECTNG,ta,ta+ws,0,h RECTNG,ta+space,ta+space+wc,tb+space,tb+space+hc AOVLAP,ALL RECTNG,0,w,0,hb+gap RECTNG,0,w,0,h AOVLAP,ALL NUMCMP,AREA ! Compress out unused area numbers APLOT ASEL,S,AREA,,2 ! Assign attributes to coil AATT,3,1,2,0 ASEL,S,AREA,,1 ! Assign attributes to armature ASEL,A,AREA,,12,13 AATT,4,1,1 ASEL,S,AREA,,3,5 ! Assign attributes to backiron ASEL,A,AREA,,7,8 AATT,2,1,1,0 /PNUM,MAT,1 ALLSEL,ALL APLOT SMRTSIZE,4 ! Set SmartSize meshing level AMESH,ALL ! Mesh all areas ESEL,S,MAT,,4 ! Select armature elements CM,ARM,ELEM ! Define armature as a component ESEL,S,MAT,,3 NSLE,S CP,1,VOLT,ALL CP,2,EMF,ALL NCOIL=NDNEXT(0) ALLSEL,ALL ARSCAL,ALL,,,.01,.01,1,,0,1 ! Scale model to MKS (meters) FINISH /SOLU ANTYP,TRANS NSEL,EXT ! Select exterior nodes D,ALL,AZ,0 ! Set potentials to zero (flux-parallel) ALLSEL,ALL D,NCOIL,VOLT,12 ! voltage load TIME,.01 DELTIM,.002 OUTRES,ALL,ALL SOLVE TIME,.03 NSUBST,1 SOLVE TIME,.06 DELTIM,.005 NSUBST,1 SOLVE FINISH /POST1 *GET,_NSET,ACTIVE,,SET,NSET *DIM,CURTIME,ARRAY,_NSET *DIM,FORCEY,ARRAY,_NSET *DIM,CUR,ARRAY,_NSET *DIM,IND,ARRAY,_NSET ! sum up forces CMSEL,S,ARM,ELEM NSLE ESLN *DO,_ISET,1,_NSET SET,,,,,,,_ISET EMFT FORCEY(_ISET)=_FYSUM *ENDDO ALLS *DO,_ISET,1,_NSET SET,,,,,,,_ISET ! get current *GET,_CUR,NODE,NCOIL,RF,AMPS ! amps per turn CUR(_ISET)=_CUR*n ! calculate inductance ETABLE,_ENER,MENE SSUM *GET,ENER,SSUM,,ITEM,_ENER IND(_ISET)=2*ENER/_CUR**2 *GET,CURTIME(_ISET),ACTIVE,,SET,TIME *ENDDO *VWRITE,'TIME','FORCE-Y','CURRENT','INDUCT' (/4a14) *VWRITE,'(SEC)',' (N)','(A-turn)',' (H)' (4a14) *VWRITE,CURTIME(1),FORCEY(1),CUR(1),IND(1) (E14.5,1x,E14.5,1x,E14.5,1x,E14.5) FINISH
Another Ansys, Inc., publication, the Mechanical APDL Verification Manual, contains an additional example of transient magnetic analysis:
VM186 - Transient Analysis of a Slot-Embedded Conductor |