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userfunctions:coulomb [Elmer/Ice Wiki]

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userfunctions:coulomb [2015/11/26 15:48]
gag [General Description]
userfunctions:coulomb [2015/12/02 12:24]
gag [General Description]
Line 33: Line 33:
   * ''Friction Law Linear Velocity'' -> <m>u_{t0}</m>     * ''Friction Law Linear Velocity'' -> <m>u_{t0}</m>  
  
-The effective pressure is defined as <m>N = -sigma_{nn} -p_w</m>,  where <m>sigma_{nn}</m> is the normal Cauchy stress and <m>p_w</m> the water pressure. If a variable ''Effective Pressure'' exists, it is used to evaluate directly <m>=</m>. Else, the normal Cauchy stress is estimated from the stress computed at previous timestep. The water pressure is prescribed as an ''External Pressure'' (Negative - Compressive convention, and therefore 'External Pressure' should be equal to the opposite of the water pressure in the sif). +The effective pressure is defined as <m>N = -sigma_{nn} -p_w</m>,  where <m>sigma_{nn}</m> is the normal Cauchy stress and <m>p_w</m> the water pressure. If a variable ''Effective Pressure'' exists, it is used to evaluate directly <m>N</m>. Else, the normal Cauchy stress is estimated from the stress computed at previous timestep. The water pressure is prescribed as an ''External Pressure'' (Negative - Compressive convention, and therefore 'External Pressure' should be equal to the opposite of the water pressure in the sif). 
              
    
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 ==== Examples ==== ==== Examples ====
-An example of the usage of the user function //Friction_Coulomb// TODO +The Coulomb friction law is tested in ''[ELMER_TRUNK]/elmerice/Tests/Friction_Coulomb'' with a direct input of the effective pressure and ''[ELMER_TRUNK]/elmerice/Tests/Friction_Coulomb_Pw'' with the effective pressure computed from the stress and a prescribed water pressure.  
  
  
userfunctions/coulomb.txt ยท Last modified: 2015/12/02 12:24 by gag
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