steel1.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 "steel1.h"
#include "sm/Materials/isolinearelasticmaterial.h"
#include "mathfem.h"
#include "classfactory.h"
 
namespace oofem {
REGISTER_Material(Steel1);
 
Steel1 :: Steel1(int n, Domain *d) : PerfectlyPlasticMaterial(n, d)
{
    linearElasticMaterial = new IsotropicLinearElasticMaterial(n, d);
}
 
 
 
double
Steel1 :: computeYCValueAt(GaussPoint *gp,
                           FloatArray *currentStress,
                           FloatArray *currentPlasticStrain) const
 
//
// computes the value of receiver.
// testing if yield condition is fulfilled
// function double      computeValueAt (GaussPoint*)
// should return zero if yield surface is reached,
//               less than zero if surface still not reached
//               > 0. if yield criteria previously violated.
//
// ig gp->status are posibly stored hardenining variables
{
    // double answer;
    return this->computeJ2InvariantAt(currentStress) - this->give('k', gp);
}
 
 
double
Steel1 :: computeJ2InvariantAt(FloatArray *currentStress) const
//
// computes the J2 value of receiver.
//
{
    double answer;
    double v1, v2, v3;
 
    if ( currentStress == NULL ) {
        return 0.0;
    }
 
    v1 = ( ( currentStress->at(1) - currentStress->at(2) ) * ( currentStress->at(1) - currentStress->at(2) ) );
    v2 = ( ( currentStress->at(2) - currentStress->at(3) ) * ( currentStress->at(2) - currentStress->at(3) ) );
    v3 = ( ( currentStress->at(3) - currentStress->at(1) ) * ( currentStress->at(3) - currentStress->at(1) ) );
 
    answer = ( 1. / 6. ) * ( v1 + v2 + v3 ) + currentStress->at(4) * currentStress->at(4) +
    currentStress->at(5) * currentStress->at(5) + currentStress->at(6) * currentStress->at(6);
 
    return sqrt(answer);
}
 
 
 
 
FloatArray *
Steel1 :: GiveYCStressGradient(GaussPoint *gp,
                               FloatArray *currentStress,
                               FloatArray *currentPlasticStrain) const
 
//
// - returning vector of derivatives of yield surface with respect to stresses.
//
// ig gp->status are posibly stored hardening variables
{
    double f, sigx, sigy, sigz, sx, sy, sz;
    FloatArray *answer = new FloatArray(6);
 
    if ( currentStress == NULL ) {
        return answer;
    }
 
    f = this->computeJ2InvariantAt(currentStress);
    sigx = currentStress->at(1);
    sigy = currentStress->at(2);
    sigz = currentStress->at(3);
 
    sx = ( 2. / 3. ) * sigx - ( 1. / 3. ) * sigy - ( 1. / 3. ) * sigz;
    sy = ( 2. / 3. ) * sigy - ( 1. / 3. ) * sigx - ( 1. / 3. ) * sigz;
    sz = ( 2. / 3. ) * sigz - ( 1. / 3. ) * sigy - ( 1. / 3. ) * sigx;
 
    answer->at(1) = 0.5 * sx / f;
    answer->at(2) = 0.5 * sy / f;
    answer->at(3) = 0.5 * sz / f;
    answer->at(4) = currentStress->at(4) / f;
    answer->at(5) = currentStress->at(5) / f;
    answer->at(6) = currentStress->at(6) / f;
 
    return answer;
}
 
 
FloatArray *
Steel1 :: GiveLCStressGradient(GaussPoint *gp,
                               FloatArray *currentStress,
                               FloatArray *currentPlasticStrain) const 
 
//
// - returning vector of derivatives of loading surface with respect to stresses.
//
// ig gp->status are posibly stored hardenining variables
{
    return this->GiveYCStressGradient(gp, currentStress, currentPlasticStrain);
}
 
 
FloatArray *
Steel1 :: GiveYCPlasticStrainGradient(GaussPoint *gp,
                                      FloatArray *currentStress,
                                      FloatArray *currentPlasticStrain) const 
 
//
//returning vector of derivatives of yield surface with respects to plastic strains
//
// ig gp->status are posibly stored hardenining variables
{
    return new FloatArray(6);
}
 
 
FloatArray *
Steel1 :: GiveLCPlasticStrainGradient(GaussPoint *gp,
                                      FloatArray *currentStress,
                                      FloatArray *currentPlasticStrain) const
 
//
//returning vector of derivatives of loading  surface with respects to plastic strains
//
// ig gp->status are posibly stored hardenining variables
{
    return this->GiveYCPlasticStrainGradient(gp, currentStress, currentPlasticStrain);
}
 
 
void
Steel1 :: initializeFrom(InputRecord &ir)
{
    PerfectlyPlasticMaterial :: initializeFrom(ir);
 
    double value;
    IR_GIVE_FIELD(ir, value, _IFT_Steel1_ry);
    propertyDictionary.add( 'k', value / sqrt(3.) );
}
} // end namespace oofem