basehyperelasticmaterial.C

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/*
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 *
 *
 *             OOFEM : Object Oriented Finite Element Code
 *
 *               Copyright (C) 1993 - 2025   Borek Patzak
 *
 *
 *
 *       Czech Technical University, Faculty of Civil Engineering,
 *   Department of Structural Mechanics, 166 29 Prague, Czech Republic
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
#include "basehyperelasticmaterial.h"
#include "dynamicinputrecord.h"
 
namespace oofem {
Tensor2_3d
BaseHyperElasticMaterial::compute_dVolumetricEnergy_dF(const Tensor2_3d &F) const
 
{
    // compute jacobian and its logarithm
    Tensor2_3d dVolumetricEnergy_dF;
    if ( VET_Type == VET_Logarithmic ) {
        auto J = F.compute_determinant();
        auto lnJ = log(J);
        dVolumetricEnergy_dF(i_3, j_3) =  K * lnJ / J * this->compute_dJ_dF(F)(i_3, j_3);
    }
    return dVolumetricEnergy_dF;
}
 
 
Tensor4_3d
BaseHyperElasticMaterial::compute_d2VolumetricEnergy_dF2(const Tensor2_3d &F) const
{
    // compute jacobian and its logarithm
 
    Tensor4_3d d2VolumetricEnergy_dF2;
    if ( VET_Type == VET_Logarithmic ) {
        auto [ J, cofF ] = F.compute_determinant_and_cofactor();
        auto lnJ = log(J);
        d2VolumetricEnergy_dF2(i_3, j_3, k_3, l_3) =  K * ( 1. - lnJ ) / J / J * cofF(i_3, j_3) * cofF(k_3, l_3) + K * lnJ / J * F.compute_tensor_cross_product()(i_3, j_3, k_3, l_3);
    }
    return d2VolumetricEnergy_dF2;
}
 
 
 
 
void
BaseHyperElasticMaterial::initializeFrom(InputRecord &ir)
{
    // volumetric energy constant, usually bulk modulus
    IR_GIVE_FIELD(ir, K, _IFT_BaseHyperElasticMaterial_k);
    //IR_GIVE_OPTIONAL_FIELD(ir, type, _IFT_BaseHyperElasticMaterial_type)
}
} // end namespace oofem