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J2PlaneStress.cpp Go to the documentation of this file. /* ****************************************************************** ** ** 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: 1.2 $ // $Date: 2001/01/23 08:46:28 $ // $Source: /usr/local/cvs/OpenSees/SRC/material/nD/J2PlaneStress.cpp,v $ // Written: Ed "C++" Love // // J2PlaneStress 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_infty + (sigma_0 - sigma_infty)*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 <J2PlaneStress.h> Vector J2PlaneStress :: strain_vec(3) ; Vector J2PlaneStress :: stress_vec(3) ; Matrix J2PlaneStress :: tangent_matrix(3,3) ; //null constructor J2PlaneStress :: J2PlaneStress( ) : J2Plasticity( ) { } //full constructor J2PlaneStress :: J2PlaneStress( int tag, double K, double G, double yield0, double yield_infty, double d, double H, double viscosity ) : J2Plasticity(tag, ND_TAG_J2PlaneStress, K, G, yield0, yield_infty, d, H, viscosity ) { } //elastic constructor J2PlaneStress :: J2PlaneStress( int tag, double K, double G ) : J2Plasticity(tag, ND_TAG_J2PlaneStress, K, G ) { } //destructor J2PlaneStress :: ~J2PlaneStress( ) { } //make a clone of this material NDMaterial* J2PlaneStress :: getCopy( ) { J2PlaneStress *clone; clone = new J2PlaneStress( ) ; //new instance of this class *clone = *this ; //asignment to make copy return clone ; } //send back type of material const char* J2PlaneStress :: getType( ) const { return "PlaneStress2D" ; } //send back order of strain in vector form int J2PlaneStress :: getOrder( ) const { return 3 ; } //get the strain and integrate plasticity equations int J2PlaneStress :: setTrialStrain( const Vector &strain_from_element ) { const double tolerance = 1e-12 ; const int max_iterations = 25 ; int iteration_counter = 0 ; int i, j, k, l ; int ii, jj ; double eps22 = strain(2,2) ; strain.Zero( ) ; strain(0,0) = strain_from_element(0) ; strain(1,1) = strain_from_element(1) ; strain(0,1) = 0.50 * strain_from_element(2) ; strain(1,0) = strain(0,1) ; strain(2,2) = eps22 ; //enforce the plane stress condition sigma_22 = 0 //solve for epsilon_22 iteration_counter = 0 ; do { this->plastic_integrator( ) ; strain(2,2) -= stress(2,2) / tangent[2][2][2][2] ; iteration_counter++ ; if ( iteration_counter > max_iterations ) { cerr << "More than " << max_iterations ; cerr << " iterations in setTrialStrain of J2PlaneStress \n" ; break ; }// end if } while ( fabs(stress(2,2)) > tolerance ) ; //modify tangent for plane stress for ( ii = 0; ii < 3; ii++ ) { for ( jj = 0; jj < 3; jj++ ) { index_map( ii, i, j ) ; index_map( jj, k, l ) ; tangent[i][j][k][l] -= tangent[i][j][2][2] * tangent[2][2][k][l] / tangent[2][2][2][2] ; //minor symmetries tangent [j][i][k][l] = tangent[i][j][k][l] ; tangent [i][j][l][k] = tangent[i][j][k][l] ; tangent [j][i][l][k] = tangent[i][j][k][l] ; } // end for jj } // end for ii return 0 ; } //unused trial strain functions int J2PlaneStress :: setTrialStrain( const Vector &v, const Vector &r ) { return this->setTrialStrain( v ) ; } int J2PlaneStress :: setTrialStrainIncr( const Vector &v ) { return -1 ; } int J2PlaneStress :: setTrialStrainIncr( const Vector &v, const Vector &r ) { return -1 ; } //send back the strain const Vector& J2PlaneStress :: getStrain( ) { strain_vec(0) = strain(0,0) ; strain_vec(1) = strain(1,1) ; strain_vec(2) = 2.0 * strain(0,1) ; return strain_vec ; } //send back the stress const Vector& J2PlaneStress :: getStress( ) { stress_vec(0) = stress(0,0) ; stress_vec(1) = stress(1,1) ; stress_vec(2) = stress(0,1) ; return stress_vec ; } //send back the tangent const Matrix& J2PlaneStress :: getTangent( ) { // matrix to tensor mapping // Matrix Tensor // ------- ------- // 0 0 0 // 1 1 1 // 2 0 1 ( or 1 0 ) // tangent_matrix(0,0) = tangent [0][0] [0][0] ; tangent_matrix(1,1) = tangent [1][1] [1][1] ; tangent_matrix(2,2) = tangent [0][1] [0][1] ; tangent_matrix(0,1) = tangent [0][0] [1][1] ; tangent_matrix(1,0) = tangent [1][1] [0][0] ; tangent_matrix(0,2) = tangent [0][0] [0][1] ; tangent_matrix(2,0) = tangent [0][1] [0][0] ; tangent_matrix(1,2) = tangent [1][1] [0][1] ; tangent_matrix(2,1) = tangent [0][1] [1][1] ; return tangent_matrix ; } //this is mike's problem int J2PlaneStress :: setTrialStrain(const Tensor &v) { return -1 ; } int J2PlaneStress :: setTrialStrain(const Tensor &v, const Tensor &r) { return -1 ; } int J2PlaneStress :: setTrialStrainIncr(const Tensor &v) { return -1 ; } int J2PlaneStress :: setTrialStrainIncr(const Tensor &v, const Tensor &r) { return -1 ; } const Tensor& J2PlaneStress :: getTangentTensor( ) { return rank4 ; } //jeremic@ucdavis.edu 22jan2001const Tensor& J2PlaneStress :: getStressTensor( ) //jeremic@ucdavis.edu 22jan2001{ //jeremic@ucdavis.edu 22jan2001 return rank2 ; //jeremic@ucdavis.edu 22jan2001} //jeremic@ucdavis.edu 22jan2001 //jeremic@ucdavis.edu 22jan2001const Tensor& J2PlaneStress :: getStrainTensor( ) //jeremic@ucdavis.edu 22jan2001{ //jeremic@ucdavis.edu 22jan2001 return rank2 ; //jeremic@ucdavis.edu 22jan2001} //this is frank's problem int J2PlaneStress :: sendSelf(int commitTag, Channel &theChannel) { return -1 ; } int J2PlaneStress :: recvSelf(int commitTag, Channel &theChannel, FEM_ObjectBroker &theBroker) { return -1 ; } //matrix_index ---> tensor indices i,j // plane stress different because of condensation on tangent // case 3 switched to 1-2 and case 4 to 3-3 void J2PlaneStress :: index_map( int matrix_index, int &i, int &j ) { switch ( matrix_index+1 ) { //add 1 for standard tensor indices case 1 : i = 1 ; j = 1 ; break ; case 2 : i = 2 ; j = 2 ; break ; case 3 : i = 1 ; j = 2 ; break ; case 4 : i = 3 ; j = 3 ; break ; case 5 : i = 2 ; j = 3 ; break ; case 6 : i = 3 ; j = 1 ; break ; default : i = 1 ; j = 1 ; break ; } //end switch i-- ; //subtract 1 for C-indexing j-- ; return ; }

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