<br />
<b>Warning</b>:  Undefined array key 1 in <b>/home/np29546/public_html/elmerice/wiki/inc/auth.php</b> on line <b>78</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/np29546/public_html/elmerice/wiki/inc/auth.php:78) in <b>/home/np29546/public_html/elmerice/wiki/inc/auth.php</b> on line <b>431</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/np29546/public_html/elmerice/wiki/inc/auth.php:78) in <b>/home/np29546/public_html/elmerice/wiki/inc/Action/Export.php</b> on line <b>104</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/np29546/public_html/elmerice/wiki/inc/auth.php:78) in <b>/home/np29546/public_html/elmerice/wiki/inc/Action/Export.php</b> on line <b>104</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/np29546/public_html/elmerice/wiki/inc/auth.php:78) in <b>/home/np29546/public_html/elmerice/wiki/inc/Action/Export.php</b> on line <b>104</b><br />
~~NOTOC~~
===== ForceToStress Solver =====

==== General Informations ====

  * **Solver Fortran File:** ''ForceToStress.f90'' 
  * **Solver Name:** ''ForceToStress'' 
  * **Required Output Variable(s):** ''Stress'' (user defined) 
  * **Required Input Variable(s):** ''Force''
  * **Optional Output Variable(s):** None
  * **Optional Input Variable(s):** None


==== General Description ====
For a given boundary, this solver computes the nodal stress equivalent to a given nodal force. Force here means the result of a variable, named stress, which is of the same units than the force but per unit-area in 3D or unit-length in 2D. This can be used also to infer the flux from the value of a debit or to infer a tangential stress from the value of a tangential force. 


==== SIF contents ====
In the SIF example below, the normal stress on a boundary is inferred from the 3rd component of the Stokes residual. 
<code>
Solver 1
  Equation = "Navier-Stokes"
  Stabilization Method = String Stabilized
  Flow Model = Stokes
  ...

  Exported Variable 1 = Flow Solution Loads[Fx:1 Fy:1 Fz:1 CEQ Residual:1 ]
  Calculate Loads = Logical True
End

Solver 2
    Equation = "ForceToStress"
    Procedure = File "ElmerIceSolvers" "ForceToStress"
    Variable = String "Stress"
    Variable DOFs = 1
    
    Force Variable Name = String "Fz"

    Linear System Solver = Direct
    Linear System Direct Method = umfpack
 End

! Solve this for body Id 2 (=boundary 3 here)
Equation 2
  Active Solvers(1) = 2
End

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Boundary Condition 3
  Target Boundaries = 5
  Body Id = 2
  ...
End
</code>


==== Examples ====

In the example found in ''[ELMER_TRUNK]/elmerice/Tests/ForceToStress'', a pressure applied on a boundary is first integrated to get  nodal force using the [[solvers:gethydrostaticloads|GetHydrostaticLoad Solver]], and then the pressure is recovered using the ''ForceToStress'' Solver.  

2 more tests were added on 15-12-2018:

[ELMER_TRUNK]/elmerice/Tests/ForceToStress_periodic: Test periodic conditions

[ELMER_TRUNK]/elmerice/Tests/ForceToStress_parallel: Test parallel solver