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ANSYS doesn't respond when avoiding picking operation (using NSEL) 1

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vidiii

Industrial
Nov 13, 2006
36
Hi,

I have a batch file where the nodes on an area must be coupled. This can be done by using the picking operation (GUI). However this is dependant on the meshsize (increase of nodes), and on the geometry of the system.

When I avoid using the GUI picking operation, and use NSEL it works fine, until I try to solve it. ANSYS doesn't respond then (and I need to shut it down manually -> crash). However I don't know the reason for this problem.

Batch by picking operation:

FLST,4,401,1,ORDE,7
FITEM,4,3118
FITEM,4,3120
FITEM,4,-3135
FITEM,4,3160
FITEM,4,-3179
FITEM,4,3208
FITEM,4,-3571
CP,1,VOLT,P51X

FLST,4,401,1,ORDE,7
FITEM,4,3988
FITEM,4,3990
FITEM,4,-4005
FITEM,4,4030
FITEM,4,-4049
FITEM,4,4078
FITEM,4,-4441
CP,2,VOLT,P51X

Batch by using NSEL (ANSYS doesn't respond when solved):

! Defining that the nodes on upper electrodes are coupeld considering the voltage.
! ANSYS crashed when the more easy command nsel was used
! It works fine in this way (selecting the nodes on upper electrodes) with the 'pick-box'
NSEL,S,LOC,Z,h_b/2+h_p,h_b/2+h_p
CP,1,VOLT,ALL

! The same for the nodes on the lower electrode
NSEL,S,LOC,Z,-h_b/2-h_p,-h_b/2-h_p
CP,2,VOLT,ALL

The reason I can't use the picking operation is that I'm running this batch with MATLAB where a certain parameter is changed in a loop, so by changing the parameter the picking operation is not correct anymore and the simulations can't be done automatically anymore.

I hope somebody can help me or has an idea to solve this issue. All help is welcome. Hope to hear from you, thanks in advance!

Kindest regards,
Mab

Full Batch file:

/COM,ANSYS MEDIA REL. 8.1 (03-15-2004) REF. VERIF. MANUAL: REL. 8.1


/PREP7
SMRT,OFF

! Define problem parameters

ET,1,SOLID226,1001 ! 3-D COUPLED-FIELD SOLID, PIEZO OPTION
ET,2,SOLID95 ! for the beam

! - Material properties for PZT5H
MP,DENS,3,7800 ! PIEZOELECTRIC DENSITY
MP,PERX,3,3800 ! PERMITTIVITY (X AND Y DIRECTION)
MP,PERY,3,3800
MP,PERZ,3,3800 ! PERMITTIVITY (Z DIRECTION)
MP,EX,2,10E10 ! BEAM MODULUS OF ELASTICITY
MP,DENS,2,8400 ! BEAM DENSITY



TB,PIEZ,3,,,1 ! DEFINE PIEZO. TABLE FOR PZT5H
TBDATA,16,2.74e-10 ! d61 PIEZOELECTRIC CONSTANT
TBDATA,14,2.74e-10 ! d52 PIEZOELECTRIC CONSTANT
TBDATA,3,-320e-12 ! d13 PIEZOELECTRIC CONSTANT
TBDATA,6,-320e-12 ! d23 PIEZOELECTRIC CONSTANT
TBDATA,9,650e-12 ! d33 PIEZOELECTRIC CONSTANT

TB,ANEL,3 ! DEFINE STRUCTURAL TABLE
TBDATA,1,6.2E10,3.1E10,3.1E10 ! INPUT [C] MATRIX
TBDATA,7,6.2E10,3.1E10
TBDATA,12,5.0E10
TBDATA,16,1E10
TBDATA,19,1E10
TBDATA,21,1E10

! - Geometry
L1 = 0.5e-3 ! Length of region 1
L2 = 7.0e-3 ! Length of region 2 --> Also 14e-3 and 21e-3
L3 = 27.424e-3 ! Length of region 3
h_b = 0.1016e-3 ! Height of the beam
h_p = 0.178e-3 ! Height of the piezoelectric
b = 8.89e-3 ! Width

! Finite element model of the piezoelectric bimorph beam
!
local,11 ! Coord. system for lower layer: polar axis +Z
local,12,,,,,,,180 ! Coord. system for upper layer: polar axis -Z (turning around Y axis)
csys,11 ! Activate coord. system 11

! Create keypoints of the beam
K,1,0,-b/2,-h_b/2
K,2,0,-b/2,h_b/2
K,3,0,b/2,h_b/2
K,4,0,b/2,-h_b/2

K,5,L3,-b/2,-h_b/2
K,6,L3,-b/2,h_b/2
K,7,L3,b/2,h_b/2
K,8,L3,b/2,-h_b/2

a,1,2,3,4 ! Create 2 areas of the beam
a,5,6,7,8

!v,1,2,3,4,5,6,7,8 ! Create volume of the beam

! Create keypoints of the piezoelectric - Lower part
K,9,L1,-b/2,h_b/2
K,10,L1,-b/2,h_b/2+h_p
K,11,L1,b/2,h_b/2+h_p
K,12,L1,b/2,h_b/2

K,13,L2,-b/2,h_b/2
K,14,L2,-b/2,h_b/2+h_p
K,15,L2,b/2,h_b/2+h_p
K,16,L2,b/2,h_b/2

a,9,10,11,12 ! Create 2 areas of the actuator - Upper part
a,13,14,15,16


! Create keypoints of the piezoelectric - Lower part
K,17,L1,-b/2,-(h_b/2)
K,18,L1,-b/2,-(h_b/2+h_p)
K,19,L1,b/2,-(h_b/2+h_p)
K,20,L1,b/2,-h_b/2

K,21,L2,-b/2,-h_b/2
K,22,L2,-b/2,-(h_b/2+h_p)
K,23,L2,b/2,-(h_b/2+h_p)
K,24,L2,b/2,-h_b/2

a,17,18,19,20 ! Create 2 areas of the actuator - Lower part
a,21,22,23,24


v,1,2,3,4,5,6,7,8 ! Create volume of the beam
v,9,10,11,12,13,14,15,16 ! Create volume of the actuator - Upper part
v,17,18,19,20,21,22,23,24 ! Create volume of the actuator - Lower part



VPLOT
/USER, 1
/FOC, 1, 0.134472237295E-01, -0.262739630989E-02, 0.00000000000
/REPLO
/VIEW, 1, -0.354977451809 , -0.671192907261 , 0.650761930317
/ANG, 1, 23.5284044493
/REPLO

FLST,2,3,6,ORDE,2 ! Glue different volumes to each other
FITEM,2,1
FITEM,2,-3
VGLUE,P51X



esize,0.27e-3 ! Specify the element length

! Selecting the volume and adding the right material and mesh properties to it

TYPE, 2 ! Mesh element 2 (Solid95)
MAT, 2 ! Material type 2 (Beam material)
REAL,
ESYS, 0 ! Normal coordinate system
SECNUM,

MSHKEY,0 ! Previous properties are attached to the beam volume
MSHAPE,1,3d
CM,_Y,VOLU
VSEL, , , , 4
CM,_Y1,VOLU
CHKMSH,'VOLU'
CMSEL,S,_Y
!*
VMESH,_Y1
!*
CMDELE,_Y
CMDELE,_Y1
CMDELE,_Y2
!*
TYPE, 1 ! Mesh element 1 (Solid226)
MAT, 3 ! Material type 1 (Piezomaterial)
REAL,
ESYS, 12 ! Z-axis 180 turned (Polarization)
SECNUM,

MSHKEY,0 ! Previous properties are attached to the upper piezoelectric actuator
MSHAPE,1,3d
CM,_Y,VOLU
VSEL, , , , 2
CM,_Y1,VOLU
CHKMSH,'VOLU'
CMSEL,S,_Y
!*
VMESH,_Y1
!*
CMDELE,_Y
CMDELE,_Y1
CMDELE,_Y2
!*

TYPE, 1 ! Mesh element 1 (Solid226)
MAT, 3 ! Material type 1 (Piezomaterial)
REAL,
ESYS, 11 ! Normal coordinate system
SECNUM,
!*
VPLOT
MSHKEY,0 ! Previous properties are attached to the lower piezoelectric actuator
MSHAPE,1,3d
CM,_Y,VOLU
VSEL, , , , 3
CM,_Y1,VOLU
CHKMSH,'VOLU'
CMSEL,S,_Y
!*
VMESH,_Y1
!*
CMDELE,_Y
CMDELE,_Y1
CMDELE,_Y2

FINISH
/SOL

FLST,2,1,5,ORDE,1 ! Left end clamped
FITEM,2,1
!*
/GO
DA,P51X,ALL,

FLST,2,2,5,ORDE,2 ! All electrodes zero voltage
FITEM,2,14
FITEM,2,18
/GO
!*
DA,P51X,VOLT,0


! Defining that the nodes on upper electrodes are coupeld considering the voltage.
! ANSYS crashed when the more easy command nsel was used
! It works fine in this way (selecting the nodes on upper electrodes) with the 'pick-box'
FLST,4,325,1,ORDE,7
FITEM,4,4580
FITEM,4,4582
FITEM,4,-4599
FITEM,4,4626
FITEM,4,-4639
FITEM,4,4662
FITEM,4,-4953
CP,1,VOLT,P51X

! The same for the nodes on the lower electrode
FLST,4,325,1,ORDE,7
FITEM,4,3860
FITEM,4,3862
FITEM,4,-3879
FITEM,4,3906
FITEM,4,-3919
FITEM,4,3942
FITEM,4,-4233
CP,2,VOLT,P51X



!*
ANTYPE,2
!*
MSAVE,0
!*
MODOPT,LANB,5
EQSLV,SPAR
MXPAND,5, , ,0
LUMPM,0
PSTRES,0
!*
MODOPT,LANB,10,5,800, ,OFF
/STATUS,SOLU
SOLVE
FINISH
 
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Hello,

I think you should use a allsel command before you solve.

Hope this helps!

Alex
 
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