J2Plasticity.h

//----------------------------------------------------------------------------
//  XC program; finite element analysis code
//  for structural analysis and design.
//
//  Copyright (C)  Luis Claudio Pérez Tato
//
//  This program derives from OpenSees <http://opensees.berkeley.edu>
//  developed by the  «Pacific earthquake engineering research center».
//
//  Except for the restrictions that may arise from the copyright
//  of the original program (see copyright_opensees.txt)
//  software es libre: usted puede redistribuirlo y/o modificarlo
//  under the terms of the GNU General Public License published by 
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This software is distributed in the hope that it will be useful, but
//  WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCANTIL o de APTITUD PARA UN PROPÓSITO DETERMINADO.
//  GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// junto a este programa.
// If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------------
/* ****************************************************************** **
**    OpenSees - Open System for Earthquake Engineering Simulation    **
**          Pacific Earthquake Engineering Research Center            **
**                                                                    **
**                                                                    **
** (C) Copyright 1999, The Regents of the University of California    **
** All Rights Reserved.                                               **
**                                                                    **
** Commercial use of this program without express permission of the   **
** University of California, Berkeley, is strictly prohibited.  See   **
** file 'COPYRIGHT'  in main directory for information on usage and   **
** redistribution,  and for a DISCLAIMER OF ALL WARRANTIES.           **
**                                                                    **
** ****************************************************************** */

// $Revision: 1.4 $
// $Date: 2003/02/14 23:01:25 $
// $Source: /usr/local/cvs/OpenSees/SRC/material/nD/J2Plasticity.h,v $

#ifndef J2Plasticity_h
#define J2Plasticity_h

// Written: Ed "C++" Love
//
// J2 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
//
//  set eta := 0 for rate independent case
//


#include <utility/matrix/Vector.h>
#include <utility/matrix/Matrix.h>
#include <material/nD/NDMaterial.h>


namespace XC{

//
//
//
//
class J2Plasticity: public NDMaterial
  {
  protected :
    //this is mike's problem
    static Tensor rank2;
    static Tensor rank4;

    //material parameters
    double bulk; 
    double shear; 
    double sigma_0; 
    double sigma_infty; 
    double delta; 
    double Hard; 
    double eta; 

    //internal variables
    Matrix epsilon_p_n; 
    Matrix epsilon_p_nplus1; 
    double xi_n; 
    double xi_nplus1; 

    //material response
    Matrix stress; 
    double tangent[3][3][3][3]; 
    static double initialTangent[3][3][3][3]; 
    static double IIdev[3][3][3][3]; 
    static double IbunI[3][3][3][3]; 

    //material input
    Matrix strain; 

    //parameters
    static const double one3;
    static const double two3;
    static const double four3;
    static const double root23;


    void zero( );//zero internal variables
    void plastic_integrator( );//plasticity integration routine
    void doInitialTangent(void) const;

    double q( double xi );//hardening function
    double qprime( double xi );//hardening function derivative

    //matrix index to tensor index mapping
    virtual void index_map( int matrix_index, int &i, int &j ) const;

    int sendData(CommParameters &);
    int recvData(const CommParameters &);
  public:
    //null constructor
    J2Plasticity();
    //full constructor
    J2Plasticity(int tag, int classTag,
                     double K,
                     double G,
                     double yield0,
                     double yield_infty,
                     double d,
                     double H,
                     double viscosity = 0 );
    J2Plasticity(int tag, int classTag);
    //elastic constructor
    J2Plasticity( int tag, int classTag, double K, double G );

    virtual NDMaterial* getCopy(const std::string &) const;

    //swap history variables
    virtual int commitState(void);
    //revert to last saved state
    virtual int revertToLastCommit(void);
    //revert to start
    virtual int revertToStart(void);

    //sending and receiving
    virtual int sendSelf(CommParameters &);
    virtual int recvSelf(const CommParameters &);

    //print out material data
    void Print(std::ostream &s, int flag = 0);

    virtual NDMaterial *getCopy(void) const;
    virtual const std::string &getType(void) const;
    virtual int getOrder(void) const;
  };

} //end of XC namespace

#endif