{"id":308227,"date":"2023-09-24T10:25:11","date_gmt":"2023-09-24T10:25:11","guid":{"rendered":"\/forum\/forums\/topic\/capacitance-analysis-of-parallel-plate-capacitors-in-mapdl\/"},"modified":"2023-09-24T10:25:11","modified_gmt":"2023-09-24T10:25:11","slug":"capacitance-analysis-of-parallel-plate-capacitors-in-mapdl","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/capacitance-analysis-of-parallel-plate-capacitors-in-mapdl\/","title":{"rendered":"Capacitance analysis of parallel plate capacitors in MAPDL"},"content":{"rendered":"

Dear everyone<\/p>\n

Hi,The following script was created to determine the fringe capacitance of parallel plate electrodes in MAPDL.<\/p>\n

———————————<\/p>\n

do,i,0,100,10 !\u5909\u6570\uff0c\u521d\u5024\uff0c\u7d42\u5024\uff0c\u5897\u5e45\u5ea6(\u30eb\u30fc\u30d7\u306e\u59cb\u307e\u308a)<\/div>\n
 <\/div>\n
fini<\/div>\n
\/cle<\/div>\n
 <\/div>\n
\/vie,1,1,1,1<\/div>\n
\/sys,del file*.png<\/div>\n
 <\/div>\n
\/PREP7<\/div>\n
 <\/div>\n
 <\/div>\n
C*** Plate dimensions (um scale)<\/div>\n
eps0=8.854e-12 ! FREE SPACE PERMITTIVITY<\/div>\n
 <\/div>\n
width = (100*1e-6) + (i*1e-6)<\/div>\n
height = 20*1e-6<\/div>\n
thickness = 3*1e-6<\/div>\n
separation = 10*1e-6<\/div>\n
 <\/div>\n
d_dmn = 10*1e-6 ! DEPTH SURROUNDING DOMAIN EXTENDS BEYOND ELECTRODES<\/div>\n
d_inf = 5*1e-6 ! DEPTH OF INFINITE BOUNDARY ELEMENT MESH<\/div>\n
 <\/div>\n
esz = 3*1e-6  ! MESH SIZE<\/div>\n
 <\/div>\n
V = 0.01 ! APPLIED VOLTAGE<\/div>\n
 <\/div>\n
 <\/div>\n
C*** Configured for electrostatic analysis of 3D 8-node elements<\/div>\n
ET,1,SOLID123<\/div>\n
 <\/div>\n
 <\/div>\n
C*** Define infinite element<\/div>\n
ET,2,111,2,1<\/div>\n
 <\/div>\n
C*** Material properties (relative dielectric constant in vacuum)<\/div>\n
!MP,PERX,1,8.854e-12 ! THIS IS ABSOLUTE PERMITTIVITY IN MKS, WHICH WORKS OK, BUT…<\/div>\n
MP,PERX,1,1 ! WE GENERALLY USE RELATIVE PERMITTIVITY INSTEAD<\/div>\n
 <\/div>\n
 <\/div>\n
 <\/div>\n
 <\/div>\n
C*** Create your first plate<\/div>\n
BLOCK,0,width,0,height,0,-thickness<\/div>\n
cm,electrode1_a,area<\/div>\n
 <\/div>\n
 <\/div>\n
C*** Create second plate<\/div>\n
asel,none<\/div>\n
BLOCK,0,width,0,height,separation,separation+thickness<\/div>\n
cm,electrode2_a,area<\/div>\n
 <\/div>\n
 <\/div>\n
C*** SURROUNDING DOMAIN<\/div>\n
alls<\/div>\n
cm,scrap1_v,volu<\/div>\n
*get,xmin,kp,,mnloc,x<\/div>\n
*get,xmax,kp,,mxloc,x<\/div>\n
*get,ymin,kp,,mnloc,y<\/div>\n
*get,ymax,kp,,mxloc,y<\/div>\n
*get,zmin,kp,,mnloc,z<\/div>\n
*get,zmax,kp,,mxloc,z<\/div>\n
vsel,none<\/div>\n
bloc,xmin-d_dmn,xmax+d_dmn,ymin-d_dmn,ymax+d_dmn,zmin-d_dmn,zmax+d_dmn<\/div>\n
cm,scrap2_v,volu<\/div>\n
alls<\/div>\n
vsbv,scrap2_v,scrap1_v<\/div>\n
 <\/div>\n
 <\/div>\n
C*** MESH<\/div>\n
esiz,esz<\/div>\n
vmes,all<\/div>\n
 <\/div>\n
 <\/div>\n
C*** ELECTRODE VOLTAGE<\/div>\n
da,electrode1_a,volt<\/div>\n
da,electrode2_a,volt,V<\/div>\n
 <\/div>\n
fini<\/div>\n
 <\/div>\n
 <\/div>\n
C*** SOLVE<\/div>\n
\/solu<\/div>\n
alls<\/div>\n
save<\/div>\n
solv<\/div>\n
fini<\/div>\n
 <\/div>\n
 <\/div>\n
C*** POST PROCESS<\/div>\n
\/post1<\/div>\n
set ! READ RESULTS INTO MADL DATABASE<\/div>\n
 <\/div>\n
etab,w,sene ! BASED ON ENERGY<\/div>\n
ssum<\/div>\n
*get,Wnet,ssum,,item,w<\/div>\n
C1 = 2*Wnet\/(V**2)<\/div>\n
 <\/div>\n
nsel,s,d,volt ! BASED ON CHARGE & VOLTAGE<\/div>\n
fsum<\/div>\n
*get,q,fsum,,item,chrg<\/div>\n
c2 = q\/v<\/div>\n
 <\/div>\n
C_nominal=eps0*(height*width)\/separation ! NOMINAL FRINGE FREE VALUE<\/div>\n
 <\/div>\n
\/tla,-0.35,0.90,Capacitance (ANSYS, energy) = %C1% Fd ! ANNOTATION<\/div>\n
\/tla,-0.35,0.85,Capacitance (ANSYS, Q\/V) = %C2% Fd<\/div>\n
\/tla,-0.35,0.80,Capacitance (nominal fringe-free) = %C_nominal% Fd<\/div>\n
 <\/div>\n
alls ! CAPPED SECTION PLOTS<\/div>\n
wpro,,,90<\/div>\n
wpof,,,width\/2<\/div>\n
\/type,1,7<\/div>\n
\/cpl,1<\/div>\n
 <\/div>\n
*enddo  !\u6307\u5b9a\u306e\u5024\u3067\u7d42\u308f\u308a<\/div>\n
 <\/div>\n
plns,volt<\/div>\n
\/sho,png $plns,volt $\/sho,close $\/wait,2<\/div>\n
plve,ef,,,,vect,,on<\/div>\n
\/sho,png $plve,ef,,,,vect,,on $\/sho,close $\/wait,2<\/div>\n
 <\/div>\n
 <\/div>\n
\/eof<\/div>\n
—————————————-<\/div>\n
The capacitance of only the overlapping electrodes can be determined by a theoretical formula, but how should the capacitance be approached taking into account the electric field of the fringes?<\/div>\n
In this script, the do syntax is turned and parsed using the length of the electrode as a parameter.<\/div>\n
 <\/div>\n
Best regards, and thank you.<\/div>\n
 <\/div>\n
Takabayashi<\/div>\n
 <\/div>\n","protected":false},"template":"","class_list":["post-308227","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t