film_thresis_02.mac

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!
! Filename: film_thresis_02.mac, ANSYS APDL script
! by <vladimir.kolchuzhin@qieee.org>
!
! Issue: 1. Geometric and FE modeling of thin film on substrate: 
!			3D FE-mesh -> *.db
!	 2. Linear static thermal analysis: T(x,y,z)
!	    Laplace's equation: [K]*{T}={Q}
!	 3. Thermal resistance calculation: Rth=dT/Q
!
! Rev.:	
!	2025-12-08 Munich
!
!==========================================================================!
!
!                           Load: heat_flux=Pin/area
!                               |||||||||||||||||	
!                               vvvvvvvvvvvvvvvvv
!                             		o---------------o
!                               | mat1          |  x---> x
!		             o---------------o---------------o---------------o 
!               |    mat2                                 SiO2  |
!		             o---------------o---------------o---------------o
!               |    mat3                                 Si    |
!               |                                               |
!		             o---------------o---------------o---------------o
!               \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ BC: Tamb
!
!                                     
!                        ASCII-Schematic of the problem
!
!==========================================================================!
!
!
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FINISH $/CLEAR $/CONTOUR,1,128	!*** if sweep ***!

/VUP,,Z

/TITLE, steady state linear heat transfer analysis
project_name='Rthermal'
!--------------------------------------------------------------------------!

/PREP7

mm=1e-3		!
um=1e-6		!
PI=2*ASIN(1)	!

!-------------------------! geometry parametrs !---------------------------!

! top film
a1=100*um
b1=100*um
arg1=2		! 0.5...2.0 um
h1=arg1*um	!*** if sweep ***!

! 
a2=300*um
b2=300*um
h2=2.0*um	

! substrate
a3=300*um
b3=300*um
h3=110*um	

area1=a1*b1

!--------------------------------------------------------------------------!
!key_BC=1	! layer 1
!key_BC=2	! layer 1+2
key_BC=3	! layer 1+2+3

! mesh quality: element size
el_size=a1/20		! 

Tamb=20			! ambient temperature

!Pin=1.0		! heat flow rate: (HEAT), Watt
heat_flux_0=3.0e+6	! 3 W/mm/mm

!heat_flux=Pin/area1	! heat flow rate per area: Heat Fluxes(HFLUX), W/m/m
heat_flux=heat_flux_0

Pin=heat_flux*area1
!--------------------------------------------------------------------------!
!----------------------! Defines elements types !--------------------------!
!--------------------------------------------------------------------------!

 !ET,1,SOLID70		!  8-Node 3D thermal brick element

ET,1,SOLID90		! 20-Node 3D thermal higher order brick element
ET,2,SOLID90		! 20-Node 3D thermal higher order brick element
ET,3,SOLID90		! 20-Node 3D thermal higher order brick element

!--------------------------------------------------------------------------!
!-------------------! Defines material properties !------------------------!
!--------------------------------------------------------------------------!
EMUNIT,MKS			!

! thermal material properties:
kth_SiO2=1.3			! SiO2 thermal conductivity, W/(m·K)
kth_Si=84			! Si   thermal conductivity, W/(m·K)
kth_Al=220			! Al   thermal conductivity, W/(m·K)
kth_Cu=380			! Cu   thermal conductivity, W/(m·K)
kth_AlN=140			! AlN  thermal conductivity, W/(m·K)
 kth_xx_AlN= 60			! AlN xx thermal conductivity 
 kth_yy_AlN= 60			! AlN yy thermal conductivity
 kth_zz_AlN=140			! AlN zz thermal conductivity

! isotropic
!mp,KXX,1,kth			! thermal conductivity mat1
mp,KXX,2,kth_SiO2		! thermal conductivity mat2
mp,KXX,3,kth_Si			! thermal conductivity mat3

! anisotropic 
mp,KXX,1,kth_xx_AlN		! xx thermal conductivity 
mp,KYY,1,kth_yy_AlN		! yy thermal conductivity
mp,KZZ,1,kth_zz_AlN		! zz thermal conductivity

!--------------------------------------------------------------------------!
!-------------------------------! Geometry !-------------------------------!
!--------------------------------------------------------------------------!

BLOCK,-a1/2,+a1/2,-b1/2,+b1/2,-h1/2,+h1/2

BLOCK,-a1/2,+a1/2,-b1/2,+b1/2,-h1/2-h2,-h1/2
BLOCK,-a2/2,+a2/2,-b2/2,+b2/2,-h1/2-h2,-h1/2

BLOCK,-a1/2,+a1/2,-b1/2,+b1/2,-h1/2-h2-h3,-h1/2-h2
BLOCK,-a2/2,+a2/2,-b2/2,+b2/2,-h1/2-h2-h3,-h1/2-h2

allsel
vovlap,all
numcmp,all

ndiv2=5
L,23,27,ndiv2 $L,11,15,ndiv2 $L,3,19,ndiv2
L,24,28,ndiv2 $L,12,16,ndiv2 $L,4,18,ndiv2
L,22,26,ndiv2 $L,10,14,ndiv2 $L,2,17,ndiv2
L,21,25,ndiv2 $L, 9,13,ndiv2 $L,1,20,ndiv2

V,28,24,23,27,16,12,11,15
V,16,12,11,15,18,4,3,19
V,26,22,21,25,14,10,9,13
V,14,10,9,13,17,2,1,20

allsel
vovlap,all
numcmp,all

!--------------------------------------------------------------------------!
!------------------------------! FEA Domain !------------------------------!
!--------------------------------------------------------------------------!
! mesh

ndiv3=5
LSEL,S,loc,z,-h1/2,+h1/2
LESIZE,ALL,,,ndiv3
ALLSEL

LSEL,S,loc,z,-h1/2-h2,-h1/2
LESIZE,ALL,,,ndiv3
ALLSEL

 !SMRTSIZE,4		! set smart size meshing level 4 (fine)
ESIZE,el_size

MAT,1 $TYPE,1
VMESH,1

MAT,2 $TYPE,2
VMESH,2,5,3
VMESH,7,9

MAT,3 $TYPE,3
VMESH,3,4
VMESH,6
VMESH,10,11

!/eof
!--------------------------------------------------------------------------!
!--------------------! Defines components for BCs !------------------------!
!--------------------------------------------------------------------------!
*if,key_BC,eq,1,then $h_Tgnd=-h1/2    	 $*endif
*if,key_BC,eq,2,then $h_Tgnd=-h1/2-h2 	 $*endif
*if,key_BC,eq,3,then $h_Tgnd=-h1/2-h2-h3 $*endif

allsel
nsel,s,loc,z,+h1/2
cm,nodes_top,node
cp,1,TEMP,all
Ntop=NDNEXT(0)

allsel
nsel,s,loc,z,h_Tgnd
cm,nodes_bottom,node
cp,2,TEMP,all
Nbottom=NDNEXT(0)

csys,0
cmsel,all $allsel
eplot
!==========================================================================!

/PNUM,MAT,1 $/NUMBER,1 $EPLOT

 !save,project_name,db,,all

!==========================================================================!
! apply load and BCs

d,Nbottom,TEMP,Tamb

asel,s,loc,z,+h1/2
SFA,all,1,HFLUX,heat_flux

cmsel,all $allsel
!==========================================================================!
!==========================================================================!
/solu

antype,static		! steady state heat transfer analysis

OUTPR,ALL,1

solve
!==========================================================================!
!==========================================================================!
/post1

plns,temp
 !ples,heat

allsel
 !FSUM,HEAT
 !*GET,Q,FSUM,0,ITEM,HEAT	! HEAT
*GET,Ttop,NODE,Ntop,TEMP	! get temperature at top surface: 25.5091888

Q=Pin

Rth=(Ttop-Tamb)/Q		! 183.6396278 K/W
!*status,Rth

Rth_a=h1/kth_AlN/(a1*b1)
!*status,Rth_a
!--------------------------------------------------------------------------!
! layer1 only:
!     Temp =  20.0004286
! PARAMETER Q =    0.3000000000E-03
! PARAMETER RTH =       1.428571429
! PARAMETER RTH_A =     1.428571429
!--------------------------------------------------------------------------!
/head,off,off,off,off,off,off
/output,%project_name%_test,dat,,append
*VWRITE,a1,b1,h1,heat_flux,Rth,Rth_a,Ttop
(7E20.12)
/output
!==========================================================================!
!==========================================================================!