J2PlaneStrain.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».
//
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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
//  GNU General Public License for more details. 
//
//
// 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            **
**                                                                    **
**                                                                    **
** (C) Copyright 1999, The Regents of the University of California    **
** All Rights Reserved.                                               **
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** 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.           **
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// $Revision: 1.5 $
// $Date: 2003/02/14 23:01:25 $
// $Source: /usr/local/cvs/OpenSees/SRC/material/nD/J2PlaneStrain.h,v $

#ifndef J2PlaneStrain_h
#define J2PlaneStrain_h

// Written: Ed "C++" Love
//
// J2PlaneStrain 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
//                    2 eps_01   }   <--- note the 2
// 
//  set eta := 0 for rate independent case
//

#include <material/nD/J2Plasticity.h>

namespace XC{
//
class J2PlaneStrain : public J2Plasticity
  {
  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: 
     //null constructor
     J2PlaneStrain( ) ;

     //full constructor
     J2PlaneStrain(   int    tag, 
                      double K,
                      double G,
                      double yield0,
                      double yield_infty,
                      double d,
                      double H,
                      double viscosity = 0 ) ;


     J2PlaneStrain(int tag) ;
     //elastic constructor
     J2PlaneStrain( 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( ) const ;

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

     //this is mike's problem
     int setTrialStrain(const Tensor &v) ;
     int setTrialStrain(const Tensor &v, const Tensor &r) ;    
     int setTrialStrainIncr(const Tensor &v) ;
     int setTrialStrainIncr(const Tensor &v, const Tensor &r) ;
     const Tensor& getTangentTensor( ) ;
     
     //jeremic@ucdavis.edu 22jan2001  const Tensor& getStressTensor( ) ;
     //jeremic@ucdavis.edu 22jan2001  const Tensor& getStrainTensor( ) ;  

     //swap history variables
     int commitState( ) ; 
     int revertToLastCommit( ) ;
     int revertToStart( ) ;
  };

} //end of XC namespace

#endif