J2ThreeDimensional.h

// -*-c++-*-
//----------------------------------------------------------------------------
//  XC program; finite element analysis code
//  for structural analysis and design.
//
//  Copyright (C)  Luis C. Pérez Tato
//
//  This program derives from OpenSees <http://opensees.berkeley.edu>
//  developed by the  «Pacific earthquake engineering research center».
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//  of the original program (see copyright_opensees.txt)
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//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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//
//
// You should have received a copy of the GNU General Public License 
// along with this program.
// If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------------
/* ****************************************************************** **
**    OpenSees - Open System for Earthquake Engineering Simulation    **
**          Pacific Earthquake Engineering Research Center            **
**                                                                    **
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** (C) Copyright 1999, The Regents of the University of California    **
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// $Revision: 1.5 $
// $Date: 2003/02/14 23:01:25 $
// $Source: /usr/local/cvs/OpenSees/SRC/material/nD/J2ThreeDimensional.h,v $

// Written: Ed "C++" Love

//
// J2ThreeDimensional isotropic hardening material class
// 
//  Elastic Model
//  sigma = K*trace(epsilion_elastic) + (2*G)*dev(epsilon_elastic)
//
//  Yield Function
//  phi(sigma,q) = || dev(sigma) ||  - sqrt(2/3)*q(xi) 
//
//  Saturation Isotropic Hardening with linear term
//  q(xi) = simga_0 + (sigma_infty - sigma_0)*exp(-delta*xi) + H*xi 
//
//  Flow Rules
//  \dot{epsilon_p} =  gamma * d_phi/d_sigma
//  \dot{xi}        = -gamma * d_phi/d_q 
//
//  Linear Viscosity 
//  gamma = phi / eta  ( if phi > 0 ) 
//
//  Backward Euler Integration Routine 
//  Yield condition enforced at time n+1 
//
//  Send strains in following format :
// 
//     strain_vec = {   eps_00
//                      eps_11
//                  eps_22            
//                    2 eps_01   
//                    2 eps_12   
//            2 eps_20    }   <--- note the 2
// 
//  set eta := 0 for rate independent case
//

#ifndef J2THREEDIMENSIONAL_H
#define J2THREEDIMENSIONAL_H

#include "J2Plasticity.h"

namespace XC{
//
class J2ThreeDimensional: public J2Plasticity
  {
//-------------------Declarations-------------------------------
  private:
    //static vectors and matrices
    static Vector strain_vec;     //strain in vector notation
    static Vector stress_vec;     //stress in vector notation
    static Matrix tangent_matrix; //material tangent in matrix notation
  public: 
    J2ThreeDimensional(int tag= 0);
    J2ThreeDimensional(   int    tag, 
             double K,
             double G,
             double yield0,
             double yield_infty,
             double d,
             double H,
             double viscosity = 0 );
    //elastic constructor
    J2ThreeDimensional( int tag, double K, double G );

    //make a clone of this material
    NDMaterial* getCopy(void) const;

    //send back type of material
    const std::string &getType(void) const;

    //send back order of strain in vector form
    int getOrder(void) const;

    //get the strain and integrate plasticity equations
    int setTrialStrain( const Vector &strain_from_element);

    //unused trial strain functions
    int setTrialStrain( const Vector &v, const Vector &r );
    int setTrialStrainIncr( const Vector &v );
    int setTrialStrainIncr( const Vector &v, const Vector &r );

    //send back the strain
    const Vector& getStrain(void) const;

    //send back the stress 
    const Vector& getStress(void) const;

    //send back the tangent 
    const Matrix& getTangent(void) const;
    const Matrix& getInitialTangent(void) const;
  }; //end of J2ThreeDimensional declaration


} //end of XC namespace

#endif