effect of thermal strain (adhesive bonding) on modal analysis

reno001 · Jan 25, 2006

Hi everybody,

Is there a tutorial or valuable example for modal analysiswith (thermal strain) pre-stress ? My work is about analysis of small structure assembled by adhesive bonding. And I want to show the effect of the thermal stress onto the resonance frequencies. I have done already a lot of runs but the results do not show some big change.

Practicly:

/SOLU ! Enter solution processor
ANTYPE,STATIC ! Static analysis
PSTRES,ON ! Flag to calculate the prestress matrix
ALLS ! Select everythings
SOLVE
FINI

/SOLU ! Enter solution processor
ANTYPE,MODAL ! Modal analysis type
! MODOPT,REDUC,6 ! Calculate 6 modes using reduced method
MODOPT,LANB,6 ! Calculate 6 modes using Block Lanczos
MXPAND,6 ! Expand all 6 modes
TOTAL,10,1 ! Requests automatic generation of (structural) DOF
PSTRESS,ON ! Flag to calculate the prestress matrix
ALLS ! Select all nodes
SOLVE ! Solve current load step
FINI

meshparts · Jan 25, 2006

Hi,

it seems to me, you've done all the right way. The changes can be small and this depends on the structure that you are solving. What kind of structure is that?

Regards
Alex

reno001 · Jan 26, 2006

Hi Mihajupb,

The structure is Piezoelectric disc cover with a copper sheet of metal. This additional part (sheet of metal) has a cup form and a hole in the middle. (Imagine a dish upside down onto a thick disc) At resonance frequency the top of the structure (dish: copper sheet) moves up and down. This structure supports a mobile part which transform the vertical displacement into a rotational motion.

This structure is assembled at 140°C and I imagine the bonding process modify (thermal strain) the resonance frequency values.

I joint my script which is quite long.

I am not sure about the element options. I was tempted to write:
ET,Bcopper,SOLID5,2 ! metal sheet
ET,BCB,SOLID5,2 ! Adhesive layers
ET,ceramic,SOLID5,3 ! Piezoelectric ceramic
ET,BCB_stand,SOLID5,2 ! Polymer stand

Any advice will be appreciated.
Best Regards
************************************************************************************************************************
! ******************************************
! *** initial start-up commands ***
!*******************************************

FINISH
/CLEAR
/OUTPUT,TERM
coef = 0.10
tp_coef = coef*100
/FILENAME,MA_V%tp_coef%xyz_6
/OUTPUT,TERM

/PREP7

! ******************************************
! *** PARAMETERS ***
!*******************************************

*ASK,adh,Creat_Adhesive_Layer_?(1=Yes,0=No),1 ! To active the adhesive layer loop
*ASK,stand,Creat_stand_?(1=Yes,0=No),1 ! Add the extra piece of glue

! *** solution parameters ***

voltage = 0 ! Voltage asigned to electrode for modal analysis
f_min = 45 E+03 ! lower frequency of interest
f_max = 90 E+03 ! upper frequency of interest
deltaf = 10 E+03 ! frequency step size in Hz
Z_s = 50 ! enter the source impedance here (Ohm)
xmesh = 4 !
ymesh = 4 !
zmesh = 1 ! number of thickness mesh divisions
*ASK,tp_b_force,Mechanical_Load_on_cymbal_?(grames),300
b_force = -tp_b_force/1000! Frictional force in Z-direction
!b_force = -0.1 ! Frictional force in Z-direction
! *ASK,n_legs,number_of_legs_?,3 ! Ask for the number of legs (default value: 3)
n_legs = 3 ! Number of legs in rotor
SECT = 10 ! Sector size (degree)

! *** geometry parameters ***

! Geometry parameters for adhesive layer

*IF,adh,EQ,1,then
*ASK,thick_al,Adhesive_layer_thickness(m),100E-6
! thick_al = 100 E-6
*ELSEIF,adh,EQ,0
thick_al = 0
*ENDIF

! Geometry parameters for PZT disc

thick_b = 1 E-3 !
radius_b = 12.5 E-3 !

! geometry parameters for cymbal

thick_c = 0.45 E-3 ! Copper sheet thickness
radius_c = 12.5 E-3 ! Outer radius of cymbal's bonding surafce
radius_d = 10 E-3 ! Inner radius of cymbal's bonding surface
radius_e = 7.05 E-3 ! Radius of cymbal's upper surface
radius_f = 2.25 E-3 ! Radius of cymbal's hole
height = 2.3 E-3 ! Height of the cymbal
radius_l = 2 E-3 ! Radius of the applied structural constraints (loads)
radius_ef = 5 E-3 ! Radius for external loads on cymbal's top surface
tol = 1 E-9 ! Tolerance for key point search

! Geometry parameters for polymer stand

th_stand = 2 E-3 !
rd_stand = coef*radius_C !

! *** program parameters ***

ceramic = 1 ! Name for material 1
Bcopper = 2 ! Name for material 2
BCB = 3 ! Name for material 3
logconst = 20 !
eps_0 = 8.854 E-12 ! relative permebility
*AFUN,RAD !
pi = ACOS(-1) ! Define pi value
*AFUN,DEG !
xi = 0.001 !
ExclMark = '!!!' !

!*******************************************************************
! *** MATERIAL PROPERTIES DECLARATION FOR CYMBAL AND CERAMIC ***
!*******************************************************************
! PZ???
dens_c = 7650 ! density in kg/m^3

eps11_c = 830*eps_0 ! epsilon_11 in F/m^2
eps33_c = 629*eps_0 ! epsilon_33 in F/m^2
e31_c = -5.04 ! e_31 in As/m^2
e33_c = 11.61 ! e_33 in As/m^2
e15_c = 9.36 ! e_24 in As/m^2

c11_c = 143 E+09 ! c_11 in N/m^2
c12_c = 72.2 E+09 ! c_12 in N/m^2
c13_c = 65.9 E+09 ! c_13 in N/m^2
c33_c = 104 E+09 ! c_33 in N/m^2
c44_c = 31.8 E+09 ! c_44 in N/m^2

! *** material declaration FOR PZT (SI units) ***
! ceramic material (disc)

MP,DENS,ceramic,dens_c ! Density

MP,PERX, ceramic,eps11_c ! eps11
MP,PERY, ceramic,eps11_c ! eps33
MP,PERZ, ceramic,eps33_c ! eps22=eps11

!Z-POLED
TB,PIEZ,ceramic
TBDATA,3,e31_c ! e31
TBDATA,9,e33_c ! e32=e31
TBDATA,6,e31_c ! e33
TBDATA,14,e15_c ! e24
TBDATA,16,e15_c ! e24=e15

TB,ANEL,ceramic
TBDATA,1,c11_c ! c11
TBDATA,2,c12_c ! c12
TBDATA,3,c13_c ! c13
TBDATA,7,c11_c ! c22=c11
TBDATA,8,c13_c ! c23=c13
TBDATA,12,c33_c ! c33
TBDATA,16,(c11_c-c12_c)/2 ! c66=(c11-c12)/2
TBDATA,19,c44_c ! c44
TBDATA,21,c44_c ! c55=c44

MP,ALPX, ceramic,3 E-6 ! CTE along X
MP,ALPY, ceramic,3 E-6 ! CTE along Y
MP,ALPZ, ceramic,3 E-6 ! CTE along Z

! *** MATERIAL DECLARATION FOR CYMBAL (SI units) ***
! BeCu (cymbal)

dens_b = 8260 ! density in kg/m^3
young_b = 115 E+09 ! N/m**2
poiss_b = 0.3 ! No unit

MP,DENS, Bcopper,dens_b ! density
MP,EX, Bcopper,young_b ! Young's modulus N/m**2
MP,EY, Bcopper,young_b ! Young's modulus N/m**2
MP,EZ, Bcopper,young_b ! Young's modulus N/m**2
MP,NUXY, Bcopper,poiss_b ! Poisson ratio
MP,NUYZ, Bcopper,poiss_b ! Poisson ratio
MP,NUXZ, Bcopper,poiss_b ! Poisson ratio
MP,ALPX, Bcopper,15 E-6 ! CTE along X
MP,ALPY, Bcopper,15 E-6 ! CTE along Y
MP,ALPZ, Bcopper,15 E-6 ! CTE along Z

MP,MURX,1,0 ! Bogey material properties to suppress error messages
MP,KXX,1,0 ! Bogey material properties to suppress error messages

! *** MATERIAL DECLARATION FOR ADHESIVE LAYER (SI units) ***
! BCB bonding

MP,DENS, BCB,930 ! Density Kg/m**3
MP,EX, BCB,2.9 E+06 ! Young's modulus N/m**2
MP,EY, BCB,2.9 E+06 ! Young's modulus N/m**2
MP,EZ, BCB,2.9 E+06 ! Young's modulus N/m**2
MP,NUXY, BCB,0.34 ! No unit
MP,NUYZ, BCB,0.34 ! No unit
MP,NUXZ, BCB,0.34 ! No unit
MP,ALPX, BCB,52 E-6 ! CTE along X
MP,ALPY, BCB,52 E-6 ! CTE along Y
MP,ALPZ, BCB,52 E-6 ! CTE along Z

!*******************************************************
! *** ELEMENT DECLARATION FOR CYMBAL AND CERAMIC ***
!*******************************************************

ET,Bcopper,SOLID5,2 ! 3-D Structural solid
! UX, UY, UZ, D.o.F.
*IF,adh,EQ,1,then
ET,BCB,SOLID5,2 ! 3-D Structural solid
*ENDIF ! UX, UY, UZ, D.o.F.

ET,ceramic,SOLID5,3 ! 3-D coupled field solid
! UX, UY, UZ, VOLT, D.o.F.
*IF,stand,EQ,1,then
ET,BCB_stand,SOLID5,2 ! 3-D Structural solid
*ENDIF ! UX, UY, UZ, D.o.F.

!********************************************
! *** geometry and grouping ***
!********************************************

! step 1: create areas in 2D
! ceramic PZT
K,1 ,0 ,0 ,0
K,2 ,0 ,coef*radius_C ,0
K,3 ,0 ,radius_d ,0
K,4 ,0 ,radius_c ,0
K,5 ,0 ,radius_c ,thick_b
K,6 ,0 ,radius_d ,thick_b
K,7 ,0 ,coef*radius_C ,thick_b
K,8 ,0 ,0 ,thick_b
A,1,2,7,8
A,7,2,3,6
A,6,3,4,5

! cymbal
K,9 ,0 ,radius_e ,thick_b+height +thick_al
K,10 ,0 ,radius_f ,thick_b+height +thick_al
K,11 ,0 ,radius_f ,thick_b+height +thick_c+thick_al
K,12 ,0 ,radius_e ,thick_b+height +thick_c+thick_al
K,13 ,0 ,radius_d ,thick_b +thick_c+thick_al
K,14 ,0 ,radius_c ,thick_b +thick_c+thick_al
K,15 ,0 ,radius_ef ,thick_b+height +thick_al
K,16 ,0 ,radius_ef ,thick_b+height +thick_c+thick_al
K,17 ,0 ,radius_c ,thick_b +thick_al
K,18 ,0 ,radius_d ,thick_b +thick_al
A,18,17,14,13
A,9,18,13,12
A,10,9,12,11

! Adhesive layer
*IF,adh,EQ,1,then
K,21 ,0 ,0 ,thick_b
K,22 ,0 ,rd_stand ,thick_b
K,23 ,0 ,radius_d ,thick_b
K,24 ,0 ,radius_c ,thick_b
K,25 ,0 ,radius_c ,thick_b +thick_al
K,26 ,0 ,radius_d ,thick_b +thick_al
K,27 ,0 ,rd_stand ,thick_b +thick_al
K,28 ,0 ,0 ,thick_b +thick_al
A,21,22,27,28
A,27,22,23,26
A,26,23,24,25
*ENDIF

! Extra stand
*IF,stand,EQ,1,then
K,31,0 ,0 ,0
K,34,0 ,0 ,-th_stand
K,35,0 ,rd_stand ,-th_stand
K,38,0 ,rd_stand ,0
A,31,34,35,38
*ENDIF

! Step 2: creat volumes and form components
ALLS
VROTAT,ALL,,,,,,1,8,90,2 !sweep all areas clockwise

! Step 3: Give a name for each component

VSEL,S,LOC,Z,thick_b+thick_al,thick_b+height+thick_c+thick_al
CM,cymbal,VOLU

*IF,adh,EQ,1,then
VSEL,S,LOC,Z,thick_b,thick_b+thick_al
CM,adhesive,VOLU
*ENDIF

*IF,stand,EQ,1,then
VSEL,S,LOC,Z,-th_stand,0
CM,STAND,VOLU
*ENDIF

VSEL,S,LOC,Z,0,thick_b
CM,piezo,VOLU

! Step 4: coloring different volumes (parts) of the device

ALLS
/COLOR, CM, RED,piezo
/COLOR, CM, BLUE,cymbal
*IF,adh,EQ,1,then
/COLOR, CM, LGRA,adhesive
*ENDIF
*IF,stand,EQ,1,then
/COLOR, CM, YELL,stand
*ENDIF

!********************************************
! *** MESHING SELECTED VOLUMES ***
!********************************************

! MESHING SELECTED VOLUMES

CMSEL,S,piezo
VATT,ceramic,,ceramic

CMSEL,S,cymbal
VATT,Bcopper,,Bcopper !Associates element attributes with the selected, unmeshed volumes

*IF,adh,EQ,1,then
CMSEL,S,ADHESIVE
VATT,BCB,,BCB, !Associates element attributes with the selected, unmeshed volumes
*ENDIF

*IF,stand,EQ,1,then
CMSEL,S,STAND
VATT,BCB,,BCB_st !Associates element attributes with the selected, unmeshed volumes
*ENDIF

*IF,adh,EQ,1,then
ESIZE,1*thick_c
*ELSEIF,adh,EQ,0
ESIZE,1*thick_c
*ENDIF

CSYS,1
LSEL,S,LOC,X,0,(999/1000)*rd_stand
LSEL,R,LOC,Z,-th_stand,thick_b
LESIZE,ALL,,,10

CSYS,0
ALLS
MSHKEY,1
MSHAPE,0
VMESH,ALL
! NUMMRG,NODE,10*tol
NUMMRG,ELEM,10*tol
FINI

!************************************************
!*** BOUNDARY CONDITIONS ***
!************************************************
/PREP7
!*** Symmetry 1/4 structure ***
NSEL,S,LOC,X,0 ! select all nodes for X = 0
D,ALL,UX,,,,, ! symetry / face

NSEL,S,LOC,Y,0 ! select all nodes for Y = 0
D,ALL,UY,,,,, ! symetry / face

!*** CLAMPING LOAD ***

*IF,stand,EQ,1,then ! Clamping if the stand exist
NSEL,S,LOC,Z,-th_stand ! select all nodes for Z = stand height
D,ALL,UX,,,,,UZ,UY ! stop nodes motion (3 directions)

*ELSEIF,stand,EQ,0,then ! Clamping if the stand does not exist
CSYS,1 ! Chose the cylindrical repere
NSEL,S,LOC,Z,0 ! select all nodes for Z = 0
NSEL,R,LOC,X,0,coef*radius_C ! select all nodes within a circle of radius r=....
D,ALL,UX,,,,,UZ,UY ! stop nodes motion (3 directions)
*ENDIF

!*** VOLTAGE LOAD ***

ASEL,S,LOC,Z,-1/1000,1/1000 ! Select the bottom electrod.
NSLA,S,1 ! Selects those nodes associated with the selected areas.
CM,mass,NODE ! Creat comp called MASS.

ASEL,S,LOC,Z,(999/1000)*thick_b,(1001/1000)*thick_b ! Select the bottom electrod.
NSLA,S,1 ! Selects those nodes associated with the selected areas.
CM,signal,NODE ! Creat comp called SIGNAL

ALLS
D,mass,VOLT,0 !
D,signal,VOLT,1 !

!*** Thermal LOAD ***
Temp_TR = 140 ! Bonding temperature parameter
Temp_TU = 20 ! Use temperature parameter
NSEL,ALL ! Select all the nodes
TREF,Temp_TR ! Set the bonding temperature
TUNIF,Temp_TU ! Set the system used temperature

FINI

!**********************************************************************
! *** MODAL ANALYSIS ***
!**********************************************************************

/SOLU ! Enter solution processor
ANTYPE,STATIC ! Static analysis
PSTRES,ON ! Flag to calculate the prestress matrix
ALLS ! Select everythings
SOLVE
FINISH

/SOLU ! Enter solution processor
ANTYPE,MODAL ! Modal analysis type
MODOPT,LANB,6 ! Calculate 6 modes using Block Lanczos
MXPAND,6 ! Expand all 6 modes
TOTAL,10,1 ! Requests automatic generation of (structural) DOF
ALLS ! Select all nodes
PSTRESS,ON
SOLVE ! Solve current load step
FINISH ! Exit active processor

/POST1 ! Enter general post-processor
SET,LIST ! List solution frequencies
*DO,i,1,6 ! Do loop from 1 to 4 with i as counter
SET,1,i ! Read solution set i (mode)
*IF,adh,EQ,1,then
Temp_DT = temp_TR-temp_TU
temp_02 = thick_al*10E+6
/TITLE,%temp_02%um adhesive layer thickness & Delta Temperature:%Temp_DT% & Mode shape %i%
*ELSEIF,adh,EQ,0
Temp_DT = temp_TR-temp_TU
/TITLE,No adhesive layer thickness & Delta Temperature:%Temp_DT% & Mode shape %i%
*ENDIF
PLDISP,1,2 ! Plot deformed shape
/VIEW,1,1,1,1
!*
PLNSOL,U,SUM,0,1
/SHOW,JPEG, ! Save the picture and results
JPEG,QUAL,100,
JPEG,ORIENT,HORIZ
JPEG,COLOR,2
JPEG,TMOD,1
/GFILE,800,
!*
/REPLOT
/SHOW,CLOSE
/WAIT,2
*ENDDO
FINISH

meshparts · Jan 27, 2006

Hi,

I have found, that all the parts of your model are not glued together. Also the relative permeability is lower then 1, this is phisically imposible. Also for material 3 the relative permeability is not defined.

I've made some changes (see below).

Also I think that the adhesive layer is too soft. If you do only the static analysis and in the post-processor you set the results coordinate system to cylindrical (RSYS,1) and the plot the displacements in radial direction (plnsol,u,x) you will see that the displacement of the copper sheet is very small.

And you apply a voltage load on the polymer stand. Is that right? The hole structure seems to have a great movement in the z direction, that I cannot explain.

You should revise your code, I think.

Regards
Alex

Code:

! ******************************************
! ***    initial start-up commands       ***
!*******************************************

FINISH
    /CLEAR
    /OUTPUT,TERM
    coef    = 0.10
    tp_coef    = coef*100
    /FILENAME,MA_V%tp_coef%xyz_6
    /OUTPUT,TERM

/PREP7

! ******************************************
! ***            PARAMETERS              ***
!*******************************************
    
    *ASK,adh,Creat_Adhesive_Layer_?(1=Yes,0=No),1    ! To active the adhesive layer loop
    *ASK,stand,Creat_stand_?(1=Yes,0=No),1        ! Add the extra piece of glue

! *** solution parameters ***
    
    voltage     =    0        ! Voltage asigned to electrode for modal analysis
    f_min        =    45E+03    ! lower frequency of interest
    f_max        =    90E+03    ! upper frequency of interest
    deltaf        =    10    E+03    ! frequency step size in Hz
    Z_s        =    50        ! enter the source impedance here (Ohm)
    xmesh        =    4        ! 
    ymesh        =    4        ! 
    zmesh        =    1        ! number of thickness mesh divisions
    *ASK,tp_b_force,Mechanical_Load_on_cymbal_?(grames),300
    b_force     =    -tp_b_force/1000! Frictional force in Z-direction
    !b_force     =    -0.1        ! Frictional force in Z-direction
    ! *ASK,n_legs,number_of_legs_?,3    ! Ask for the number of legs (default value: 3)
    n_legs         =    3        ! Number of legs in rotor
    SECT        =    10        ! Sector size (degree)

! *** geometry parameters ***

! Geometry parameters for adhesive layer
    
*IF,adh,EQ,1,then
    *ASK,thick_al,Adhesive_layer_thickness(m),100E-6
!    thick_al     =     100    E-6
*ELSEIF,adh,EQ,0
    thick_al    =    0
*ENDIF 

! Geometry parameters for PZT disc

    thick_b     =     1    E-3    ! 
    radius_b    =     12.5    E-3    ! 

! geometry parameters for cymbal

    thick_c     =     0.45    E-3    ! Copper sheet thickness
    radius_c     =     12.5    E-3     ! Outer radius of cymbal's bonding surafce
    radius_d     =     10    E-3     ! Inner radius of cymbal's bonding surface
    radius_e     =     7.05    E-3     ! Radius of cymbal's upper surface
    radius_f     =     2.25    E-3     ! Radius of cymbal's hole
    height         =     2.3    E-3     ! Height of the cymbal
    radius_l     =     2    E-3     ! Radius of the applied structural constraints (loads)
    radius_ef     =    5    E-3    ! Radius for external loads on cymbal's top surface
    tol        =    1    E-9    ! Tolerance for key point search

! Geometry parameters for polymer stand

    th_stand     =     2    E-3    ! 
    rd_stand    =     coef*radius_C    ! 

! *** program parameters ***

    ceramic        =    1        ! Name for material 1
    Bcopper        =    2        ! Name for material 2
    BCB        =    3        ! Name for material 3
    logconst    =    20        ! 
    eps_0       =    1	!8.854E-12    !!!
    *AFUN,RAD                ! 
    pi          =    ACOS(-1)    ! Define pi value
    *AFUN,DEG                ! 
    xi          =    0.001        ! 
    ExclMark    =    '!!!'        ! 

!*******************************************************************
! ***   MATERIAL PROPERTIES DECLARATION FOR CYMBAL AND CERAMIC   ***
!*******************************************************************
! PZ???
    dens_c         =     7650        ! density in kg/m^3

    eps11_c     =     830*eps_0    ! epsilon_11 in F/m^2
    eps33_c     =    629*eps_0    ! epsilon_33 in F/m^2
    e31_c        =     -5.04        ! e_31 in As/m^2
    e33_c        =     11.61        ! e_33 in As/m^2
    e15_c        =     9.36        ! e_24 in As/m^2

    c11_c        =     143      E+09    ! c_11 in N/m^2
    c12_c        =     72.2     E+09    ! c_12 in N/m^2
    c13_c        =     65.9     E+09    ! c_13 in N/m^2
    c33_c        =     104      E+09    ! c_33 in N/m^2
    c44_c        =     31.8     E+09    ! c_44 in N/m^2
    
! *** material declaration FOR PZT (SI units) ***
! ceramic material (disc)

    MP,DENS,ceramic,dens_c            ! Density

    MP,PERX,    ceramic,eps11_c        ! eps11
    MP,PERY,    ceramic,eps11_c        ! eps33
    MP,PERZ,    ceramic,eps33_c        ! eps22=eps11

    !Z-POLED
    TB,PIEZ,ceramic
    TBDATA,3,e31_c                ! e31
    TBDATA,9,e33_c                ! e32=e31
    TBDATA,6,e31_c                ! e33
    TBDATA,14,e15_c                ! e24
    TBDATA,16,e15_c                ! e24=e15

    TB,ANEL,ceramic
    TBDATA,1,c11_c                ! c11
    TBDATA,2,c12_c                ! c12
    TBDATA,3,c13_c                ! c13
    TBDATA,7,c11_c                ! c22=c11
    TBDATA,8,c13_c                ! c23=c13
    TBDATA,12,c33_c                ! c33
    TBDATA,16,(c11_c-c12_c)/2        ! c66=(c11-c12)/2
    TBDATA,19,c44_c                ! c44
    TBDATA,21,c44_c                ! c55=c44

    MP,ALPX,    ceramic,3    E-6    ! CTE along X
    MP,ALPY,    ceramic,3    E-6    ! CTE along Y
    MP,ALPZ,    ceramic,3    E-6    ! CTE along Z

! ***   MATERIAL DECLARATION FOR CYMBAL (SI units) ***
! BeCu (cymbal)

    dens_b    =     8260             ! density in kg/m^3
    young_b    =     115    E+09         ! N/m**2
    poiss_b    =     0.3             ! No unit

    MP,DENS,    Bcopper,dens_b        ! density
    MP,EX,        Bcopper,young_b        ! Young's modulus N/m**2
    MP,EY,        Bcopper,young_b        ! Young's modulus N/m**2
    MP,EZ,        Bcopper,young_b        ! Young's modulus N/m**2
    MP,NUXY,    Bcopper,poiss_b        ! Poisson ratio
    MP,NUYZ,    Bcopper,poiss_b        ! Poisson ratio
    MP,NUXZ,    Bcopper,poiss_b        ! Poisson ratio
    MP,ALPX,    Bcopper,15    E-6    ! CTE along X
    MP,ALPY,    Bcopper,15    E-6    ! CTE along Y
    MP,ALPZ,    Bcopper,15    E-6    ! CTE along Z

    MP,MURX,1,0                ! Bogey material properties to suppress error messages
    MP,KXX,1,0                 ! Bogey material properties to suppress error messages

! ***   MATERIAL DECLARATION FOR ADHESIVE LAYER (SI units) ***
! BCB bonding 

    MP,DENS,    BCB,930            ! Density Kg/m**3
    MP,EX,        BCB,2.9     E+06    ! Young's modulus N/m**2
    MP,EY,        BCB,2.9     E+06    ! Young's modulus N/m**2
    MP,EZ,        BCB,2.9     E+06    ! Young's modulus N/m**2
    MP,NUXY,    BCB,0.34        ! No unit
    MP,NUYZ,    BCB,0.34        ! No unit
    MP,NUXZ,    BCB,0.34        ! No unit
    MP,ALPX,    BCB,52        E-6    ! CTE along X
    MP,ALPY,    BCB,52        E-6    ! CTE along Y
    MP,ALPZ,    BCB,52        E-6    ! CTE along Z

!*******************************************************
! ***   ELEMENT DECLARATION FOR CYMBAL AND CERAMIC   ***
!*******************************************************

ET,ceramic,SOLID5,3            ! 3-D coupled field solid
                       				 ! UX, UY, UZ, VOLT, D.o.F.
ET,Bcopper,SOLID5,2            ! 3-D Structural solid
                       				 ! UX, UY, UZ, D.o.F.
*IF,adh,EQ,1,then
ET,BCB,SOLID5,2                ! 3-D Structural solid
*ENDIF                    		! UX, UY, UZ, D.o.F.



!********************************************
! ***     geometry and grouping           ***
!********************************************

! step 1: create areas in 2D
    ! ceramic PZT
    K,1    ,0    ,0        ,0
    K,2    ,0    ,coef*radius_C    ,0
    K,3    ,0    ,radius_d    ,0
    K,4    ,0    ,radius_c    ,0
    K,5    ,0    ,radius_c    ,thick_b
    K,6    ,0    ,radius_d    ,thick_b
    K,7    ,0    ,coef*radius_C    ,thick_b
    K,8    ,0    ,0        ,thick_b
    A,1,2,7,8
    A,7,2,3,6
    A,6,3,4,5

    ! cymbal
    K,9    ,0    ,radius_e    ,thick_b+height        +thick_al
    K,10    ,0    ,radius_f    ,thick_b+height        +thick_al
    K,11    ,0    ,radius_f    ,thick_b+height    +thick_c+thick_al
    K,12    ,0    ,radius_e    ,thick_b+height    +thick_c+thick_al
    K,13    ,0    ,radius_d    ,thick_b    +thick_c+thick_al
    K,14    ,0    ,radius_c    ,thick_b    +thick_c+thick_al
    K,15    ,0    ,radius_ef    ,thick_b+height        +thick_al
    K,16    ,0    ,radius_ef    ,thick_b+height    +thick_c+thick_al
    K,17    ,0    ,radius_c    ,thick_b        +thick_al
    K,18    ,0    ,radius_d    ,thick_b        +thick_al
    A,18,17,14,13
    A,9,18,13,12
    A,10,9,12,11

    ! Adhesive layer
*IF,adh,EQ,1,then
    K,21    ,0    ,0        ,thick_b
    K,22    ,0    ,rd_stand    ,thick_b
    K,23    ,0    ,radius_d    ,thick_b
    K,24    ,0    ,radius_c    ,thick_b
    K,25    ,0    ,radius_c    ,thick_b    +thick_al
    K,26    ,0    ,radius_d    ,thick_b    +thick_al
    K,27    ,0    ,rd_stand    ,thick_b    +thick_al
    K,28    ,0    ,0        ,thick_b    +thick_al
    A,21,22,27,28
    A,27,22,23,26
    A,26,23,24,25
*ENDIF 

    ! Extra stand
*IF,stand,EQ,1,then
    K,31,0    ,0        ,0
    K,34,0    ,0        ,-th_stand
    K,35,0    ,rd_stand    ,-th_stand
    K,38,0    ,rd_stand    ,0
    A,31,34,35,38
*ENDIF

! Step 2: creat volumes and form components
nummrg,kp!!! merge keypoints and lines, works just like aglue but much faster

    ALLS
    VROTAT,ALL,,,,,,kp(0,0,0),kp(0,0, th_stand),90,2 !!! now it works for all numbering

! Step 3: Give a name for each component

    VSEL,S,LOC,Z,thick_b+thick_al,thick_b+height+thick_c+thick_al
    CM,cymbal,VOLU
    
*IF,adh,EQ,1,then
    VSEL,S,LOC,Z,thick_b,thick_b+thick_al
    CM,adhesive,VOLU
*ENDIF 

*IF,stand,EQ,1,then
    VSEL,S,LOC,Z,-th_stand,0
    CM,STAND,VOLU
*ENDIF 

    VSEL,S,LOC,Z,0,thick_b
    CM,piezo,VOLU

! Step 4: coloring different volumes (parts) of the device

    ALLS
    /COLOR, CM, RED,piezo
    /COLOR, CM, BLUE,cymbal
    *IF,adh,EQ,1,then
    /COLOR, CM, LGRA,adhesive
    *ENDIF 
    *IF,stand,EQ,1,then
    /COLOR, CM, YELL,stand
    *ENDIF 
    
!********************************************
! ***   MESHING SELECTED VOLUMES          ***
!********************************************
    
! MESHING SELECTED VOLUMES

    CMSEL,S,piezo
    VATT,ceramic,,ceramic

    CMSEL,S,cymbal
    VATT,Bcopper,,Bcopper    !Associates element attributes with the selected, unmeshed volumes

*IF,adh,EQ,1,then
    CMSEL,S,ADHESIVE
    VATT,BCB,,BCB,    !Associates element attributes with the selected, unmeshed volumes
*ENDIF 

*IF,stand,EQ,1,then
    CMSEL,S,STAND
    VATT,BCB,,BCB !!! It was BCB_st instead of PCB
*ENDIF 

    *IF,adh,EQ,1,then
          ESIZE,1*thick_c
    *ELSEIF,adh,EQ,0
        ESIZE,1*thick_c
    *ENDIF 

    CSYS,1
    LSEL,S,LOC,X,0,(999/1000)*rd_stand
    LSEL,R,LOC,Z,-th_stand,thick_b
    LESIZE,ALL,,,10

    CSYS,0
    ALLS
    MSHKEY,1
    MSHAPE,0
    VMESH,ALL
!    NUMMRG,NODE,10*tol
 !   NUMMRG,ELEM,10*tol !!! not necesary enymore
FINI

!************************************************
!***     BOUNDARY CONDITIONS                  ***
!************************************************
/PREP7
!***    Symmetry 1/4 structure ***
    NSEL,S,LOC,X,0            ! select all nodes for X = 0
    D,ALL,UX,,,,,            ! symetry / face

    NSEL,S,LOC,Y,0            ! select all nodes for Y = 0
    D,ALL,UY,,,,,            ! symetry / face

!***    CLAMPING LOAD ***

*IF,stand,EQ,1,then            ! Clamping if the stand exist
    NSEL,S,LOC,Z,-th_stand        ! select all nodes for Z = stand height
    D,ALL,UX,,,,,UZ,UY        ! stop nodes motion (3 directions)
    
*ELSEIF,stand,EQ,0,then            ! Clamping if the stand does not exist
    CSYS,1                ! Chose the cylindrical repere
    NSEL,S,LOC,Z,0            ! select all nodes for Z = 0
    NSEL,R,LOC,X,0,coef*radius_C    ! select all nodes within a circle of radius r=....
    D,ALL,UX,,,,,UZ,UY        ! stop nodes motion (3 directions)
*ENDIF 

!***   VOLTAGE LOAD  ***    

    ASEL,S,LOC,Z,-1/1000,1/1000    ! Select the bottom electrod.
    NSLA,S,1            ! Selects those nodes associated with the selected areas.
    CM,mass,NODE            ! Creat comp called MASS.

    ASEL,S,LOC,Z,(999/1000)*thick_b,(1001/1000)*thick_b    ! Select the bottom electrod.
    NSLA,S,1            ! Selects those nodes associated with the selected areas.
    CM,signal,NODE            ! Creat comp called SIGNAL
    
    ALLS
    D,mass,VOLT,0            ! 
    D,signal,VOLT,1            ! 

!***   Thermal LOAD ***
    Temp_TR    =    140        ! Bonding temperature parameter
    Temp_TU    =    20        ! Use temperature parameter
    NSEL,ALL            ! Select all the nodes
    TREF,Temp_TR            ! Set the bonding temperature
    TUNIF,Temp_TU            ! Set the system used temperature

FINI

!**********************************************************************
! ***                    MODAL ANALYSIS                             ***
!**********************************************************************

/SOLU                   ! Enter solution processor
    ANTYPE,STATIC                  ! Static analysis
    PSTRES,ON                      ! Flag to calculate the prestress matrix
    ALLS                ! Select everythings
    SOLVE !!! Here you get a warning: the material property perx for material 3 is undefined
FINISH

/eof

/SOLU                   ! Enter solution processor
    ANTYPE,MODAL            ! Modal analysis type
    MODOPT,LANB,6            ! Calculate 6 modes using Block Lanczos 
    MXPAND,6            ! Expand all 6 modes
    TOTAL,10,1            ! Requests automatic generation of (structural) DOF
    ALLS                ! Select all nodes
!    PSTRES,ON !!! I corrected this command, it was pstress instead of pstres. but that was not the problem.
    SOLVE                ! Solve current load step
FINISH                    ! Exit active processor

/eof

/POST1                    ! Enter general post-processor
    SET,LIST            ! List solution frequencies
    *DO,i,1,6            ! Do loop from 1 to 4 with i as counter
        SET,1,i            ! Read solution set i (mode)
        *IF,adh,EQ,1,then
            Temp_DT    =    temp_TR-temp_TU
            temp_02 = thick_al*10E+6
            /TITLE,%temp_02%um adhesive layer thickness & Delta Temperature:%Temp_DT% & Mode shape %i%
        *ELSEIF,adh,EQ,0
            Temp_DT    =    temp_TR-temp_TU
            /TITLE,No adhesive layer thickness & Delta Temperature:%Temp_DT% & Mode shape %i%
        *ENDIF 
        PLDISP,1,2        ! Plot deformed shape
        /VIEW,1,1,1,1  
        !*  
        PLNSOL,U,SUM,0,1
        /SHOW,JPEG,        ! Save the picture and results
        JPEG,QUAL,100,  
        JPEG,ORIENT,HORIZ   
        JPEG,COLOR,2
        JPEG,TMOD,1 
        /GFILE,800, 
        !*  
        /REPLOT 
        /SHOW,CLOSE 
        /WAIT,2
    *ENDDO
FINISH

/eof

reno001 · Jan 29, 2006

Hello Alex,

First many thanks for your help.

I imagine you have spent some time on my script and some interesting and useful remarks came out of your email.

I am going to do some comment on the top of your comments:

- The model was not glued together. I use the NUMMRG command on the nodes and I always think that was the best I could do. Your tip is very good, especially when I add the bonding layer. I still do not understand why everything is right without but as soon as I add this layer some problems come out. The next runs may show your tip solved my problem.
- The PSTRES command was misspelling. And that could explain why I could not get what I am looking for (influence of bonding process)…..
- The relative permeability is lower than 1 for the ceramic. This is the way my Piezoelectric material is. (catalog data)
- The material 3 does not need relative permeability because this is the polymer (BCB)
I think you got this message because you added the lines: BCB=3; Bcopper=2; Ceramic=1 and you removed BCB_stand. Ansys got confuse.
I have never used these lines and I leave Ansys with the following command lines:

MP,DENS, BCB, 930 ! Density Kg/m**3
MP,EX, BCB, 2.9 E+06 ! Young's modulus N/m**2
ET, BCB, SOLID5,2 ! 3-D Structural solid

Am I wrong????

- Yes, the Young modulus for BCB is wrong. I checked and the right value is 2.6 E+9
- The following line was wrong: VATT,BCB,,BCB_st !Associates ….
the correct line is : VATT,BCB,,BCB_stand !Associates ….
The stand has special element type but similar material properties. I am still waiting for the real values. The fabrication team is still working on. They are trying different designs. Exactly I was thinking to modify the Polymer (BCB) element type to consider a shell element. I found other scripts which are using this technique for thin electrodes. I guess this make the calculation faster.
I am right?

Finally, to answer your latest question: I apply the load on the top and bottom of the disc. The electrodes are not in the numerical design. The whole disc squeezes itself along the radius and the copper part has to follow this displacement. The radial displacement occur a vertical displacement ( along Z). The structure use this displacement the produce a rotational motion through a additional part we set on the top. This is a real smart micro-motor…

I hope I have been clear enough.

Anyway, I think you help me to do one step forward in my task and this worth gold.

Renaud / Post-Doc / Nanotechnology Group / Material department / Cranfield University/ England

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