transducer problem

[izyk]

Hi
I'm trying to simulate a membrane under an electrostatic field using transducers. If i generate transducer elements for each node of the membrane in one step, it works good (the results correspond to the theoretical equation).

Now I'm trying to generate two levels of transducers. I generated transducers correctly but results were not correct. So I generated transducers in two steps but the distance between was the same. It should give the same result like in first simulation but it wasn't. (membrane's deflection (Z displacement): 1 level - 0.0612, 2 level 0.052) Increasing number of levels gives bigger difference (ex. 9 levels - 0.216). Where is the problem?

Here are the scripts:

----------------------------------------------------------
transducers in one step
----------------------------------------------------------

FINISH
/CLEAR
/CWD,'C:\temp\ansys'

!* membrane
Lm=300
Wm=300
Tm=5
!* membrane_division
b=30
!* electrode_distance
h1=-0.3

dif=20

!*dimension de l'electrode
a2=75/Lm

!* voltage
v=20

/PREP7

ET,1,SHELL93
R,1,Tm

ET,2,TRANS126

MP,EX,1,130e+9*1e-6
MP,DENS,1,2330*1e-18
MP,PRXY,1,0.278

WPOFFS,0,0,dif
RECTNG,0,Lm,0,Wm
WPOFFS,0,0,-dif

LESIZE,ALL,,,b

MSHAPE,0,2D
MSHKEY,1
AMESH,ALL

!* transducer

NSEL,S,LOC,Z,dif

NSLE,U,MID !* do not apply a force at middle nodes

CM,tr1,NODE
ALLSEL,ALL

EMTGEN,'tr1','EMTELM1','EMTPNO1','UZ',h1,0,1E-02,0.8854E-05

!* applying loads and BC

NSEL,S,LOC,Z,dif+h1
NSEL,A,LOC,Z,dif+h2
D,ALL,,0,,,,UZ
D,ALL,VOLT,0

CMSEL,S,tr1
D,ALL,VOLT,v

NSEL,S,LOC,X,0
NSEL,A,LOC,X,Lm
NSEL,A,LOC,Y,0
NSEL,A,LOC,Y,Wm

D,ALL,UX,0
D,ALL,UY,0
D,ALL,UZ,0
D,ALL,ROTX,0
D,ALL,ROTY,0
D,ALL,ROTZ,0

ALLSEL,ALL

FINISH

/SOLU
ANTYPE,STATIC

SOLVE
FINISH

----------------------------------------------------------
transducers in two step
----------------------------------------------------------

.......the same as above........

h1=-0.3 !the same distance
h2=-0.3
a2=75/Lm !half membrane's length, border beetwen levels

!* transducer

NSEL,S,LOC,Z,dif
NSLE,U,MID !* do not apply a force at middle nodes
CM,tr,NODE !* all nodes

!*2nd level

NSEL,S,LOC,Z,dif
NSEL,R,LOC,X,a2*Lm,(1-a2)*Lm
NSEL,R,LOC,Y,a2*Lm,(1-a2)*Lm

NSLE,U,MID !* Ne pas appliquer de force sur les noeuds médians

CM,tr2,NODE
ALLSEL,ALL

!1ere

NSEL,S,LOC,Z,dif

NSLE,U,MID !* Ne pas appliquer de force sur les noeuds médians

CMSEL,U,tr2 ! remove nodes which corresponds to 2nd level

CM,tr1,NODE
ALLSEL,ALL

EMTGEN,'tr2','EMTELM2','EMTPNO2','UZ',h2,0,1E-02,0.8854E-05
EMTGEN,'tr1','EMTELM1','EMTPNO1','UZ',h1,0,1E-02,0.8854E-05

NSEL,S,LOC,Z,dif+h1
NSEL,A,LOC,Z,dif+h2
D,ALL,,0,,,,UZ
D,ALL,VOLT,0

...........the same as above............