ExplicitMPM.hpp

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/*
 * ------------------------------------------------------------------------------------------------------------
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 * Copyright (c) 2018-2020 Lawrence Livermore National Security LLC
 * Copyright (c) 2018-2020 The Board of Trustees of the Leland Stanford Junior University
 * Copyright (c) 2018-2020 TotalEnergies
 * Copyright (c) 2019-     GEOSX Contributors
 * All rights reserved
 *
 * See top level LICENSE, COPYRIGHT, CONTRIBUTORS, NOTICE, and ACKNOWLEDGEMENTS files for details.
 * ------------------------------------------------------------------------------------------------------------
 */
 
 
#ifndef GEOSX_PHYSICSSOLVERS_CONTACT_EXPLICITMPM_HPP_
#define GEOSX_PHYSICSSOLVERS_CONTACT_EXPLICITMPM_HPP_
 
#include "constitutive/solid/SolidUtilities.hpp"
#include "physicsSolvers/solidMechanics/kernels/ExplicitFiniteStrain.hpp"
#include "physicsSolvers/solidMechanics/MPMSolverFields.hpp"
 
namespace geos
{
 
namespace solidMechanicsMPMKernels
{
 
// A helper function to calculate polar decomposition. TODO: Previously this was an LvArray method, hopefully it will be again someday.
GEOS_HOST_DEVICE
void polarDecomposition( real64 (& R)[3][3],
                         real64 const (&matrix)[3][3] )
{
  // Initialize
  LvArray::tensorOps::copy< 3, 3 >( R, matrix );
  real64 RInverse[3][3] = { {0} },
         RInverseTranspose[3][3] = { {0} },
         RRTMinusI[3][3] = { {0} };
 
  // Higham Algorithm
  real64 errorSquared = 1.0;
  real64 tolerance = 10 * LvArray::NumericLimits< real64 >::epsilon;
  int iter = 0;
  while( errorSquared > tolerance * tolerance && iter < 100 )
  {
    iter++;
    errorSquared = 0.0;
 
    // Average the current R with its inverse tranpose
    LvArray::tensorOps::internal::SquareMatrixOps< 3 >::invert( RInverse, R );
    LvArray::tensorOps::transpose< 3, 3 >( RInverseTranspose, RInverse );
    LvArray::tensorOps::add< 3, 3 >( R, RInverseTranspose );
    LvArray::tensorOps::scale< 3, 3 >( R, 0.5 );
 
    // Determine how close R is to being orthogonal using L2Norm(R.R^T-I)
    real64 copyR[3][3];
    LvArray::tensorOps::copy< 3, 3 >( copyR, R );
    LvArray::tensorOps::Rij_eq_AikBjk< 3, 3, 3 >( RRTMinusI, R, copyR );
    LvArray::tensorOps::addIdentity< 3 >( RRTMinusI, -1.0 );
    for( std::ptrdiff_t i = 0; i < 3; i++ )
    {
      for( std::ptrdiff_t j = 0; j < 3; j++ )
      {
        errorSquared += RRTMinusI[i][j] * RRTMinusI[i][j];
      }
    }
  }
  if( iter == 100 )
  {
    GEOS_LOG_RANK( "Polar decomposition did not converge in 100 iterations!" );
  }
}
 
 
struct StateUpdateKernel
{
  template< typename POLICY, typename CONSTITUTIVE_WRAPPER >
  static void launch( SortedArrayView< localIndex const > const indices,
                      CONSTITUTIVE_WRAPPER const & constitutiveWrapper,
                      real64 dt,
                      arrayView3d< real64 const > const deformationGradient,
                      arrayView3d< real64 const > const fDot,
                      arrayView3d< real64 const > const velocityGradient,
                      arrayView2d< real64 > const particleStress )
  {
    arrayView3d< real64, solid::STRESS_USD > const oldStress = constitutiveWrapper.m_oldStress;
    // arrayView3d< real64, solid::STRESS_USD > const newStress = constitutiveWrapper.m_newStress;
 
    // Perform constitutive call
    forAll< POLICY >( indices.size(), [=] GEOS_HOST_DEVICE ( localIndex const k )
    {
      // Particle index
      localIndex const p = indices[k];
 
      // Copy the beginning-of-step particle stress into the constitutive model's m_oldStress - this fixes the MPI sync issue on Lassen for
      // some reason
      #if defined(GEOSX_USE_CUDA)
      LvArray::tensorOps::copy< 6 >( oldStress[p][0], particleStress[p] );
      #endif
 
      // Determine the strain increment in Voigt notation
      real64 strainIncrement[6];
      strainIncrement[0] = velocityGradient[p][0][0] * dt;
      strainIncrement[1] = velocityGradient[p][1][1] * dt;
      strainIncrement[2] = velocityGradient[p][2][2] * dt;
      strainIncrement[3] = (velocityGradient[p][1][2] + velocityGradient[p][2][1]) * dt;
      strainIncrement[4] = (velocityGradient[p][0][2] + velocityGradient[p][2][0]) * dt;
      strainIncrement[5] = (velocityGradient[p][0][1] + velocityGradient[p][1][0]) * dt;
 
      // Get old F by incrementing backwards
      real64 fOld[3][3] = { {0} };
      real64 fNew[3][3] = { {0} };
      LvArray::tensorOps::copy< 3, 3 >( fNew, deformationGradient[p] );
      LvArray::tensorOps::copy< 3, 3 >( fOld, deformationGradient[p] );
      LvArray::tensorOps::scaledAdd< 3, 3 >( fOld, fDot[p], -dt );
 
      // Polar decompositions
      real64 rotBeginning[3][3] = { {0} };
      real64 rotEnd[3][3] = { {0} };
      polarDecomposition( rotBeginning, fOld );
      polarDecomposition( rotEnd, fNew );
 
      // Call stress update
      real64 stress[6] = { 0 };
      constitutive::SolidUtilities::hypoUpdate2_StressOnly( constitutiveWrapper,  // the constitutive model
                                                            p,                    // particle local index
                                                            0,                    // particles have 1 quadrature point
                                                            dt,                   // time step size
                                                            strainIncrement,      // particle strain increment
                                                            rotBeginning,         // beginning-of-step rotation matrix
                                                            rotEnd,               // end-of-step rotation matrix
                                                            stress );             // final updated stress
 
      // Copy the updated stress into particleStress
      LvArray::tensorOps::copy< 6 >( particleStress[p], stress );
 
      // Copy m_newStress into m_oldStress
      constitutiveWrapper.saveConvergedState( p, 0 );
    } );
  }
};
 
} // namespace solidMechanicsMPMKernels
 
} // namespace geos
 
 
#endif /* GEOSX_PHYSICSSOLVERS_CONTACT_EXPLICITMPM_HPP_ */