Line data    Source code

       1              : // Copyright 2024, UChicago Argonne, LLC
       2              : // All Rights Reserved
       3              : // Software Name: NEML2 -- the New Engineering material Model Library, version 2
       4              : // By: Argonne National Laboratory
       5              : // OPEN SOURCE LICENSE (MIT)
       6              : //
       7              : // Permission is hereby granted, free of charge, to any person obtaining a copy
       8              : // of this software and associated documentation files (the "Software"), to deal
       9              : // in the Software without restriction, including without limitation the rights
      10              : // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
      11              : // copies of the Software, and to permit persons to whom the Software is
      12              : // furnished to do so, subject to the following conditions:
      13              : //
      14              : // The above copyright notice and this permission notice shall be included in
      15              : // all copies or substantial portions of the Software.
      16              : //
      17              : // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
      18              : // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      19              : // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
      20              : // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
      21              : // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
      22              : // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
      23              : // THE SOFTWARE.
      24              : 
      25              : #include "neml2/models/solid_mechanics/PerzynaPlasticFlowRate.h"
      26              : #include "neml2/tensors/Scalar.h"
      27              : #include "neml2/tensors/functions/heaviside.h"
      28              : #include "neml2/tensors/functions/abs.h"
      29              : #include "neml2/tensors/functions/pow.h"
      30              : #include "neml2/tensors/functions/log.h"
      31              : 
      32              : namespace neml2
      33              : {
      34              : register_NEML2_object(PerzynaPlasticFlowRate);
      35              : 
      36              : OptionSet
      37            2 : PerzynaPlasticFlowRate::expected_options()
      38              : {
      39            2 :   OptionSet options = PlasticFlowRate::expected_options();
      40            2 :   options.doc() =
      41              :       "Perzyna's viscous approximation of the consistent yield envelope (with a power "
      42              :       "law), i.e. \\f$ \\dot{\\gamma} = \\left( \\frac{\\left< f \\right>}{\\eta} \\right)^n \\f$, "
      43              :       "where \\f$ f \\f$ is the yield function, \\f$ \\eta \\f$ is the reference stress, and \\f$ "
      44            2 :       "n \\f$ is the power-law exponent.";
      45              : 
      46            4 :   options.set_parameter<TensorName<Scalar>>("reference_stress");
      47            4 :   options.set("reference_stress").doc() = "Reference stress";
      48              : 
      49            4 :   options.set_parameter<TensorName<Scalar>>("exponent");
      50            2 :   options.set("exponent").doc() = "Power-law exponent";
      51              : 
      52            2 :   return options;
      53            0 : }
      54              : 
      55            5 : PerzynaPlasticFlowRate::PerzynaPlasticFlowRate(const OptionSet & options)
      56              :   : PlasticFlowRate(options),
      57           15 :     _eta(declare_parameter<Scalar>("eta", "reference_stress", /*allow_nonlinear=*/true)),
      58           25 :     _n(declare_parameter<Scalar>("n", "exponent", /*allow_nonlinear=*/true))
      59              : {
      60            5 : }
      61              : 
      62              : void
      63           10 : PerzynaPlasticFlowRate::set_value(bool out, bool dout_din, bool /*d2out_din2*/)
      64              : {
      65              :   // Compute the Perzyna approximation of the yield surface
      66           10 :   auto Hf = heaviside(Scalar(_f));
      67           10 :   auto f_abs = abs(Scalar(_f));
      68           10 :   auto gamma_dot_m = pow(f_abs / _eta, _n);
      69           10 :   auto gamma_dot = gamma_dot_m * Hf;
      70              : 
      71           10 :   if (out)
      72            9 :     _gamma_dot = gamma_dot;
      73              : 
      74           10 :   if (dout_din)
      75              :   {
      76            5 :     auto dgamma_dot_df = _n / f_abs * gamma_dot;
      77              : 
      78            5 :     if (_f.is_dependent())
      79            5 :       _gamma_dot.d(_f) = dgamma_dot_df;
      80              : 
      81           15 :     if (const auto * const eta = nl_param("eta"))
      82            1 :       _gamma_dot.d(*eta) = -_n * gamma_dot / _eta;
      83              : 
      84           15 :     if (const auto * const n = nl_param("n"))
      85            1 :       _gamma_dot.d(*n) = gamma_dot * log(f_abs / _eta);
      86            5 :   }
      87           10 : }
      88              : } // namespace neml2