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Thermal induced stress in bimetal structure.

Thermal induced stress in bimetal structure.

Thermal induced stress in bimetal structure.

(OP)
Hi Folks,

Model description:
Two materials stripes are bond together at 200°C. The whole structure is cool down to 20°C. Due to coefficient thermal expansion mismatch, the residual thermal-stress produces deformation. Thus the end of the cantilever bends. (the other end is clamped)

I wrote this script to compare the different elements available in the Ansys library.
Help file proposes to use the shell element to solve the thermal-strain problem in the multilayer components but I want to do the same thing using a 2D element (and if possible PLANE13) in order to investigate the stress in the forthcoming adhesive layer (The adhesive layer is not in this FE model)

Displacement at the end of the bimetal stripe. (room temperature)
           PLANE 2:            20um
           PLANE 183:        20um
           PLANE182:         20um
           PLANE 42,0,1:    20um
           PLANE13,3,0:     24.6um
           PLANE13,3,1:     26.7um

I want to use PLANE13 in the further steps of my project but the thermal-strain deformation is far too different to the other elements. And I do not know why.

Question: Why is the result from PLANE13 so different?
Is there any way to tune it?

Best Regards

Renaud

FINISH
/CLEAR
/OUTPUT,TERM
/PREP7
ET,1,PLANE13,3,1,0    !
!ET,1,PLANE2,0,0,0    !
!ET,1,PLANE183,0,0,0    !
!ET,1,PLANE182,0,0,0    !
!ET,1,PLANE42,0,1,0    !
!     * material 1 = Titanium *
    MP,DENS,  1,   7700         ! Kg/m^3 Density
    MP,EX,    1,   100 E+9 !Young's modulus
    MP,NUXY,  1,   0.34         ! Poisson ratio
    MP,ALPX,  1,   10 E-6     ! CTE all range of temperature
 ! * Material 2 = Ceramic *        
    MP,DENS,  2,   7700          ! Kg/m^3 Density
    MP,EX,    2,   76 E+9   !Young's modulus
    MP,NUXY,  2,   0.30          ! Poisson ratio
    MP,ALPX,  2,   50 E-6        ! CTE all range of temperature

RECTNG, 0,    0.010,   0,          0.000100
RECTNG, 0,    0.010,   0.000100,   0.001100
NUMMRG,KP,1E-9
ASEL,S,LOC,Y, 0,       0.000100     !Titanium
AATT,1,,1
ASEL,S,LOC,Y, 0.0001,   0.001100    !Ceramic
AATT,2,,1
ESIZE,0.0001
MSHAPE,0,2D            
MSHKEY,1            
ASEL,S,area,,1,3,,        
AMESH,all
NUMMRG,NODE,1E-9
  NSEL,S,LOC,X,-1E-9,+1E-9
  NSEL,R,LOC,Y,+1.1E-3,+1.101E-3
    D,ALL,UX,,,,,UY
    NSEL,S,LOC,X,-1E-9,+1E-9
    DSYM,SYMM,x
    TREF,   200        ! Bonding temperature
    TUNIF,  20    ! Room temperature
    FINISH
/SOLU
    ALLS
    ANTYPE,STATIC               ! Static analysis
!    CNVTOL,F,,,,0.001                ! Convergence based on force only
    SOLVE
    FINISH
/POST1  
/EFACE,1
AVPRIN,0, ,
!*  
PLNSOL,U,Y,0,1  

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