SIF file in PIEZO example

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bomastudio
Posts: 36
Joined: 22 Aug 2012, 13:43
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SIF file in PIEZO example

Post by bomastudio »

I need some help to understand deeper the following *.SIF file (in particular the material part and the load case):

Code: Select all

Header
  Mesh DB "." "."
End

Constants
End

Simulation
  Max Output Level = 3
  Coordinate System = Cartesian 2D
  Simulation Type = Steady State
  Steady State Max Iterations = 5
  Steady State Min Iterations = 1
  Output Intervals = 1
  Output File = "piezo.result"
  Post File = "piezo.ep"
End

Body 1
  Equation = 1
  Material = 1
  Body Force = 1
End

Body 2
  Equation = 1
  Material = 2
  Body Force = 2
End

Body Force 1

  Stress BodyForce 2 = -1e8

  Piezo Material = Logical True

!  Stress(3) = Variable Electric Field 2
!   Real
!      0  -1e8 0  0
!      1  -1e8 0  0
!    End
End

Body Force 2

  Stress BodyForce 2 = -1e8

  Piezo Material = Logical True

!  Stress(3) = Variable Electric Field 2
!    Real 
!      0  1 0 0
!      1  1 0 0
!    End
End

Equation 1
  Active Solvers(2) = 1 2
End

Solver 2
  Equation = Electrostatics
  Variable = Potential
  Variable DOFs = 1
  Procedure = "StatElecSolve" "StatElecSolver"
  Linear System Solver = Direct
  Linear System Direct Method = UMFPack
  Linear System Iterative Method = BiCGStab
  Linear System Preconditioning = ILU1
  Linear System Max Iterations = 500
  Linear System Convergence Tolerance = 1.0e-8
  Nonlinear System Newton After Tolerance = 1.0e-3
  Nonlinear System Newton After Iterations = 20
  Nonlinear System Max Iterations = 1000
  Nonlinear System Convergence Tolerance = 1.0e-5
  Nonlinear System Relaxation Factor = 1.0
  Steady State Convergence Tolerance = 1.0e-4
End

Solver 1
! Exec SOlver = Never
  Equation = Stress Analysis
  Variable = Displacement
  Variable DOFs = 2
  Linear System Solver = Direct
  Linear System Direct Method = UMFPack
  Linear System Iterative Method = BiCGStab
  Linear System Preconditioning = ILU1
  Linear System Max Iterations = 500
  Linear System Convergence Tolerance = 1.0e-8
  Nonlinear System Newton After Tolerance = 1.0e-3
  Nonlinear System Newton After Iterations = 20
  Nonlinear System Max Iterations = 1
  Nonlinear System Convergence Tolerance = 1.0e-5
  Nonlinear System Relaxation Factor = 1.0
  Steady State Convergence Tolerance = 1.0e-4
End

Material 1
   Density = 2e3
   Youngs Modulus = 70e9
   Poisson Ratio = 0.3
   Relative Permittivity = 1
	
   Piezo Material Coefficients(2,4) = Real \
	0 10 0 0 \
        10 0 0 0


End

Material 2
   Density = 2e3
   Youngs Modulus = 70e9
   Poisson Ratio = 0.3
   Relative Permittivity = 1
	
   Piezo Material Coefficients(2,4) = Real \
	0  -10 0 0 \
        -10 0 0 0


End

Boundary Condition 1
  Target Boundaries(2) = 1 2   !  5 6
  Displacement 1 = 0
  Displacement 2 = 0
End

Boundary Condition 2
  Target Boundaries = 3

  Potential = 0
End

Boundary Condition 3
  Target Boundaries = 4

  Potential = 1
End

$fprintf( stderr, "TEST CASE 1\n");
RUN
$fprintf( stderr, "END TEST CASE 1: Target NRM=0.595127795559, EPS=1.0e-3\n" );
thank all for any help! :D
Last edited by bomastudio on 21 Sep 2012, 21:25, edited 1 time in total.
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: SIF file

Post by mzenker »

Hi,

there are obviously piezoelectric materials in this case. This seems to be an undocumented feature (at least there is no mention in the tutorials or models manual), so the question (and the request for documentation in the models manual) goes to the Elmer team. ;)
Apart from that, what is it that you don't understand?

Matthias
bomastudio
Posts: 36
Joined: 22 Aug 2012, 13:43
Antispam: Yes

Re: SIF file

Post by bomastudio »

I can't understand two things:
The Body Force parte

Code: Select all

Body Force 1

  Stress BodyForce 2 = -1e8

  Piezo Material = Logical True

!  Stress(3) = Variable Electric Field 2
!   Real
!      0  -1e8 0  0
!      1  -1e8 0  0
!    End
End
the part ! Stress(3) etc (what defines? and the '!' what means?)


and the definition of the material

Code: Select all

Material 1
   Density = 2e3
   Youngs Modulus = 70e9
   Poisson Ratio = 0.3
   Relative Permittivity = 1
   
   Piezo Material Coefficients(2,4) = Real \
   0 10 0 0 \
        10 0 0 0


End
the section

Piezo Material Coefficients(2,4) = Real \
0 10 0 0 \
10 0 0 0

what mean? and where write this part in ElmerGUI? in the free text box?
Thanx!
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: SIF file

Post by mzenker »

the part ! Stress(3) etc (what defines? and the '!' what means?)
"!" means that this is commented out.
Stress(3) seems to define a stress tensor.
and where write this part in ElmerGUI? in the free text box?
Yes, that is what I would try.

HTH,

Matthias
bomastudio
Posts: 36
Joined: 22 Aug 2012, 13:43
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Re: SIF file

Post by bomastudio »

Thnak you Matthias! :D :D
bomastudio
Posts: 36
Joined: 22 Aug 2012, 13:43
Antispam: Yes

Re: SIF file

Post by bomastudio »

:oops: :oops: I cant' inside this part

Code: Select all

Body Force 1

  Stress BodyForce 2 = -1e8

  Piezo Material = Logical True
where choose Piezo Material = Logical True. How input it?
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: SIF file

Post by mzenker »

Hi,

how about the free text field in the body force?

Matthias
bomastudio
Posts: 36
Joined: 22 Aug 2012, 13:43
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Re: SIF file

Post by bomastudio »

:oops: :oops: :oops: ah! thanx.....
bomastudio
Posts: 36
Joined: 22 Aug 2012, 13:43
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Re: SIF file in PIEZO example

Post by bomastudio »

Can someone tell me what type of matrix is the following:

Code: Select all

Piezo Material Coefficients(2,4) = Real \
0 10 0 0 \
10 0 0 0
I think that it must be the coupling matrix for the PZT but I can't understand why it is a 2x4 (I suppose that the non-zero terms are the poling direction coefficients). Any theoric reference? :?:
raback
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Re: SIF file in PIEZO example

Post by raback »

Hi

I guess it is the matrix for the direct piezoelectric effect. See
http://en.wikipedia.org/wiki/Piezoelectricity

It is 2x4 because we are working in 2D case. In 3D it would be 3x6.

-Peter
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