Example #1
0
void
Kinematics<EvalT, Traits>::evaluateFields(typename Traits::EvalData workset)
{
  minitensor::Tensor<ScalarT> F(num_dims_), strain(num_dims_), gradu(num_dims_);
  minitensor::Tensor<ScalarT> I(minitensor::eye<ScalarT>(num_dims_));

  // Compute DefGrad tensor from displacement gradient
  if (!def_grad_rc_) {
    for (int cell(0); cell < workset.numCells; ++cell) {
      for (int pt(0); pt < num_pts_; ++pt) {
        gradu.fill(grad_u_, cell, pt, 0, 0);
        F            = I + gradu;
        j_(cell, pt) = minitensor::det(F);
        for (int i(0); i < num_dims_; ++i) {
          for (int j(0); j < num_dims_; ++j) {
            def_grad_(cell, pt, i, j) = F(i, j);
          }
        }
      }
    }
  } else {
    bool first = true;
    for (int cell = 0; cell < workset.numCells; ++cell) {
      for (int pt = 0; pt < num_pts_; ++pt) {
        gradu.fill(grad_u_, cell, pt, 0, 0);
        F = I + gradu;
        for (int i = 0; i < num_dims_; ++i)
          for (int j = 0; j < num_dims_; ++j)
            def_grad_(cell, pt, i, j) = F(i, j);
        if (first && check_det(workset, cell, pt)) first = false;
        // F[n,0] = F[n,n-1] F[n-1,0].
        def_grad_rc_.multiplyInto<ScalarT>(def_grad_, cell, pt);
        F.fill(def_grad_, cell, pt, 0, 0);
        j_(cell, pt) = minitensor::det(F);
      }
    }
  }

  if (weighted_average_) {
    ScalarT jbar, weighted_jbar, volume;
    for (int cell(0); cell < workset.numCells; ++cell) {
      jbar   = 0.0;
      volume = 0.0;
      for (int pt(0); pt < num_pts_; ++pt) {
        jbar += weights_(cell, pt) * j_(cell, pt);
        volume += weights_(cell, pt);
      }
      jbar /= volume;

      for (int pt(0); pt < num_pts_; ++pt) {
        weighted_jbar = (1 - alpha_) * jbar + alpha_ * j_(cell, pt);
        F.fill(def_grad_, cell, pt, 0, 0);
        const ScalarT p = std::pow((weighted_jbar / j_(cell, pt)), 1. / 3.);
        F *= p;
        j_(cell, pt) = weighted_jbar;
        for (int i(0); i < num_dims_; ++i) {
          for (int j(0); j < num_dims_; ++j) {
            def_grad_(cell, pt, i, j) = F(i, j);
          }
        }
      }
    }
  }

  if (needs_strain_) {
    if (!def_grad_rc_) {
      for (int cell(0); cell < workset.numCells; ++cell) {
        for (int pt(0); pt < num_pts_; ++pt) {
          gradu.fill(grad_u_, cell, pt, 0, 0);
          strain = 0.5 * (gradu + minitensor::transpose(gradu));
          for (int i(0); i < num_dims_; ++i) {
            for (int j(0); j < num_dims_; ++j) {
              strain_(cell, pt, i, j) = strain(i, j);
            }
          }
        }
      }
    } else {
      for (int cell = 0; cell < workset.numCells; ++cell) {
        for (int pt = 0; pt < num_pts_; ++pt) {
          F.fill(def_grad_, cell, pt, 0, 0);
          gradu = F - I;
          // dU/dx[0] = dx[n]/dx[0] - dx[0]/dx[0] = F[n,0] - I.
          // strain = 1/2 (dU/dx[0] + dU/dx[0]^T).
          strain = 0.5 * (gradu + minitensor::transpose(gradu));
          for (int i = 0; i < num_dims_; ++i)
            for (int j = 0; j < num_dims_; ++j)
              strain_(cell, pt, i, j) = strain(i, j);
        }
      }
    }
  }
}
Example #2
0
  void MechanicsResidual<EvalT, Traits>::
  evaluateFields(typename Traits::EvalData workset)
  {
    std::cout.precision(15);
    // initilize Tensors
    Intrepid::Tensor<ScalarT> F(num_dims_), P(num_dims_), sig(num_dims_);
    Intrepid::Tensor<ScalarT> I(Intrepid::eye<ScalarT>(num_dims_));

    if (have_pore_pressure_) {
      for (std::size_t cell=0; cell < workset.numCells; ++cell) {
        for (std::size_t pt=0; pt < num_pts_; ++pt) {

          // Effective Stress theory
          sig.fill( &stress_(cell,pt,0,0) );
          sig -= biot_coeff_(cell,pt) * pore_pressure_(cell,pt) * I;

          for (std::size_t i=0; i<num_dims_; i++) {
            for (std::size_t j=0; j<num_dims_; j++) {
              stress_(cell,pt,i,j) = sig(i,j);
            }
          }
        }
      }
    }

    // initialize residual
    if(have_strain_){
      // for small deformation, use Cauchy stress
      for (std::size_t cell=0; cell < workset.numCells; ++cell) {
        for (std::size_t node=0; node < num_nodes_; ++node) {
          for (std::size_t dim=0; dim<num_dims_; ++dim)  {
            residual_(cell,node,dim)=0.0;
          }
        }
        for (std::size_t pt=0; pt < num_pts_; ++pt) {
          //F.fill( &def_grad_(cell,pt,0,0) );
          sig.fill( &stress_(cell,pt,0,0) );

          for (std::size_t node=0; node < num_nodes_; ++node) {
            for (std::size_t i=0; i<num_dims_; ++i) {
              for (std::size_t j=0; j<num_dims_; ++j) {
                residual_(cell,node,i) +=
                  sig(i, j) * w_grad_bf_(cell, node, pt, j);
              }
            }
          }
        }
      }

    }
    else {
      // for large deformation, map Cauchy stress to 1st PK stress
      for (std::size_t cell=0; cell < workset.numCells; ++cell) {
        for (std::size_t node=0; node < num_nodes_; ++node) {
          for (std::size_t dim=0; dim<num_dims_; ++dim)  {
            residual_(cell,node,dim)=0.0;
          }
        }
        for (std::size_t pt=0; pt < num_pts_; ++pt) {
          F.fill( &def_grad_(cell,pt,0,0) );
          sig.fill( &stress_(cell,pt,0,0) );

          // map Cauchy stress to 1st PK
          P = Intrepid::piola(F,sig);

          for (std::size_t node=0; node < num_nodes_; ++node) {
            for (std::size_t i=0; i<num_dims_; ++i) {
              for (std::size_t j=0; j<num_dims_; ++j) {
                residual_(cell,node,i) +=
                  P(i, j) * w_grad_bf_(cell, node, pt, j);
              }
            }
          }
        }
      }
    }

    
    // optional body force
    if (have_body_force_) {
      for (std::size_t cell=0; cell < workset.numCells; ++cell) {
        for (std::size_t node=0; node < num_nodes_; ++node) {
          for (std::size_t pt=0; pt < num_pts_; ++pt) {
            for (std::size_t dim=0; dim<num_dims_; ++dim)  {
              residual_(cell,node,dim) += 
                w_bf_(cell,node,pt) * body_force_(cell,pt,dim);
            }
          }
        }
      }
    }
  }