lspacebb.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 "sm/Elements/3D/lspacebb.h"
#include "fei3dhexalin.h"
#include "gausspoint.h"
#include "floatmatrix.h"
#include "floatarray.h"
#include "classfactory.h"
 
#ifdef __OOFEG
 #include "oofeggraphiccontext.h"
 #include "oofegutils.h"
#endif
 
namespace oofem {
REGISTER_Element(LSpaceBB);
 
LSpaceBB :: LSpaceBB(int n, Domain *aDomain) : LSpace(n, aDomain)
{ }
 
void
LSpaceBB :: computeBmatrixAt(GaussPoint *gp, FloatMatrix &answer, int li, int ui)
// Returns the [6x24] strain-displacement matrix {B} of the receiver, eva-
// luated at gp.
// B matrix  -  6 rows : epsilon-X, epsilon-Y, epsilon-Z, gamma-YZ, gamma-ZX, gamma-XY  :
{
    FloatMatrix dnx, dnx0;
    FloatArray coord(3);
 
    answer.resize(6, 24);
    answer.zero();
    coord.zero();
 
 
    LSpace :: interpolation.evaldNdx( dnx, gp->giveNaturalCoordinates(), FEIElementGeometryWrapper(this) );
    LSpace :: interpolation.evaldNdx( dnx0, coord, FEIElementGeometryWrapper(this) );
 
    // deviatoric part fully integrated, volumetric part in one point
    // here we follow BBar approach
    //
    // construct BB = B(gp) + Pv [B(0)-B(gp)]
    // where Pv is volumetric projection mtrx
    // B(gp) is original geometrical matrix evalueated at gp
    // B(0)  is geometrical matrix evalueated at centroid
    //
    // assemble Pv [B(0)-B(gp)]
    for ( int i = 1; i <= 8; i++ ) {
        answer.at(1, 3 * i - 2) = answer.at(2, 3 * i - 2) = answer.at(3, 3 * i - 2) = ( dnx0.at(i, 1) - dnx.at(i, 1) ) / 3.0;
        answer.at(1, 3 * i - 1) = answer.at(2, 3 * i - 1) = answer.at(3, 3 * i - 1) = ( dnx0.at(i, 2) - dnx.at(i, 2) ) / 3.0;
        answer.at(1, 3 * i - 0) = answer.at(2, 3 * i - 0) = answer.at(3, 3 * i - 0) = ( dnx0.at(i, 3) - dnx.at(i, 3) ) / 3.0;
    }
 
    // add B(gp)
    for ( int i = 1; i <= 8; i++ ) {
        answer.at(1, 3 * i - 2) += dnx.at(i, 1);
        answer.at(2, 3 * i - 1) += dnx.at(i, 2);
        answer.at(3, 3 * i - 0) += dnx.at(i, 3);
    }
 
    for ( int i = 1; i <= 8; i++ ) {
        answer.at(4, 3 * i - 1) += dnx.at(i, 3);
        answer.at(4, 3 * i - 0) += dnx.at(i, 2);
 
        answer.at(5, 3 * i - 2) += dnx.at(i, 3);
        answer.at(5, 3 * i - 0) += dnx.at(i, 1);
 
        answer.at(6, 3 * i - 2) += dnx.at(i, 2);
        answer.at(6, 3 * i - 1) += dnx.at(i, 1);
    }
}
} // end namespace oofem