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Bidirectional.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. ** ** ** ** Developed by: ** ** Frank McKenna (fmckenna@ce.berkeley.edu) ** ** Gregory L. Fenves (fenves@ce.berkeley.edu) ** ** Filip C. Filippou (filippou@ce.berkeley.edu) ** ** ** ** ****************************************************************** */ // $Revision: 1.6 $ // $Date: 2003/02/14 23:01:33 $ // $Source: /usr/local/cvs/OpenSees/SRC/material/section/Bidirectional.cpp,v $ #include <Bidirectional.h> #include <Channel.h> Vector Bidirectional::s(2); Matrix Bidirectional::ks(2,2); ID Bidirectional::code(2); Bidirectional::Bidirectional (int tag, double e, double sy, double Hi, double Hk) : SectionForceDeformation(tag, SEC_TAG_Bidirectional), E(e), sigY(sy), Hiso(Hi), Hkin(Hk) { for (int i = 0; i < 2; i++) { eP_n[i] = 0.0; eP_n1[i] = 0.0; q_n[i] = 0.0; q_n1[i] = 0.0; } alpha_n = 0.0; alpha_n1 = 0.0; code(0) = SECTION_RESPONSE_VY; code(1) = SECTION_RESPONSE_P; } Bidirectional::Bidirectional(): SectionForceDeformation(0, SEC_TAG_Bidirectional), E(0.0), sigY(0.0), Hiso(0.0), Hkin(0.0) { for (int i = 0; i < 2; i++) { eP_n[i] = 0.0; eP_n1[i] = 0.0; q_n[i] = 0.0; q_n1[i] = 0.0; } alpha_n = 0.0; alpha_n1 = 0.0; code(0) = SECTION_RESPONSE_VY; code(1) = SECTION_RESPONSE_P; } Bidirectional::~Bidirectional() { // Nothing to do here } int Bidirectional::setTrialSectionDeformation(const Vector &e) { e_n1[0] = e(0); e_n1[1] = e(1); return 0; } const Matrix& Bidirectional::getSectionTangent(void) { // Compute trial stress using elastic tangent s(0) = E*(e_n1[0]-eP_n[0]); s(1) = E*(e_n1[1]-eP_n[1]); static Vector xsi(2); // Predicted stress minus back stress xsi(0) = s(0) - q_n[0]; xsi(1) = s(1) - q_n[1]; double normxsi = xsi.Norm(); // Current yield stress double sigY_n = sigY + alpha_n*Hiso; // Yield function double f_n1 = normxsi - sigY_n; // Elastic step if (f_n1 < 0.0) { ks(0,0) = ks(1,1) = E; ks(0,1) = ks(1,0) = 0.0; } // Plastic step else { // Consistency parameter double dlam = f_n1/(E+Hkin+Hiso); double n_n1[2]; // Normal vector n_n1[0] = xsi(0)/normxsi; n_n1[1] = xsi(1)/normxsi; double A = E*(E/(Hiso+Hkin+E)); double B = E*(E*dlam/normxsi); //ks(0,0) = E - A*n_n1[0]*n_n1[0] - B*(1.0 - n_n1[0]*n_n1[0]); //ks(1,1) = E - A*n_n1[1]*n_n1[1] - B*(1.0 - n_n1[1]*n_n1[1]); //ks(0,1) = -A*n_n1[0]*n_n1[1] - B*(-n_n1[0]*n_n1[1]); //ks(1,0) = ks(0,1); double EB = E-B; double BA = B-A; ks(0,0) = EB + BA*n_n1[0]*n_n1[0]; ks(1,1) = EB + BA*n_n1[1]*n_n1[1]; ks(0,1) = BA*n_n1[0]*n_n1[1]; ks(1,0) = ks(0,1); //n_n1[0] *= dlam; //n_n1[1] *= dlam; // Update plastic strains //eP_n1[0] = eP_n[0] + n_n1[0]; //eP_n1[1] = eP_n[1] + n_n1[1]; // Update back stress //q_n1[0] = q_n[0] + Hkin*n_n1[0]; //q_n1[1] = q_n[1] + Hkin*n_n1[1]; // Update effective plastic strain //alpha_n1 = alpha_n + dlam; } return ks; } const Matrix& Bidirectional::getInitialTangent(void) { ks(0,0) = ks(1,1) = E; ks(0,1) = ks(1,0) = 0.0; return ks; } const Vector& Bidirectional::getStressResultant(void) { // Compute trial stress using elastic tangent s(0) = E*(e_n1[0]-eP_n[0]); s(1) = E*(e_n1[1]-eP_n[1]); static Vector xsi(2); // Predicted stress minus back stress xsi(0) = s(0) - q_n[0]; xsi(1) = s(1) - q_n[1]; double normxsi = xsi.Norm(); // Current yield stress double sigY_n = sigY + alpha_n*Hiso; // Yield function double f_n1 = normxsi - sigY_n; // Elastic step if (f_n1 < 0.0) { // do nothing } // Plastic step else { // Consistency parameter double dlam = f_n1/(E+Hkin+Hiso); double n_n1[2]; // Normal vector n_n1[0] = xsi(0)/normxsi; n_n1[1] = xsi(1)/normxsi; n_n1[0] *= dlam; n_n1[1] *= dlam; // Return stresses to yield surface s(0) -= E*n_n1[0]; s(1) -= E*n_n1[1]; // Update plastic strains eP_n1[0] = eP_n[0] + n_n1[0]; eP_n1[1] = eP_n[1] + n_n1[1]; // Update back stress q_n1[0] = q_n[0] + Hkin*n_n1[0]; q_n1[1] = q_n[1] + Hkin*n_n1[1]; // Update effective plastic strain alpha_n1 = alpha_n + dlam; } return s; } const Vector& Bidirectional::getSectionDeformation(void) { // Write to static variable for return s(0) = e_n1[0]; s(1) = e_n1[1]; return s; } int Bidirectional::commitState(void) { eP_n[0] = eP_n1[0]; eP_n[1] = eP_n1[1]; q_n[0] = q_n1[0]; q_n[1] = q_n1[1]; alpha_n = alpha_n1; return 0; } int Bidirectional::revertToLastCommit(void) { return 0; } int Bidirectional::revertToStart(void) { for (int i = 0; i < 2; i++) { eP_n[i] = 0.0; eP_n1[i] = 0.0; q_n[i] = 0.0; q_n1[i] = 0.0; } alpha_n = 0.0; alpha_n1 = 0.0; return 0; } SectionForceDeformation* Bidirectional::getCopy(void) { Bidirectional *theCopy = new Bidirectional (this->getTag(), E, sigY, Hiso, Hkin); for (int i = 0; i < 2; i++) { theCopy->eP_n[i] = eP_n[i]; theCopy->eP_n1[i] = eP_n1[i]; theCopy->q_n[i] = q_n[i]; theCopy->q_n1[i] = q_n1[i]; } theCopy->alpha_n = alpha_n; theCopy->alpha_n1 = alpha_n1; return theCopy; } const ID& Bidirectional::getType(void) { return code; } int Bidirectional::getOrder(void) const { return 2; } int Bidirectional::sendSelf(int cTag, Channel &theChannel) { int res = 0; static Vector data(10); data(0) = this->getTag(); data(1) = E; data(2) = sigY; data(3) = Hiso; data(4) = Hkin; data(5) = eP_n[0]; data(6) = eP_n[1]; data(7) = q_n[0]; data(8) = q_n[1]; data(9) = alpha_n; res = theChannel.sendVector(this->getDbTag(), cTag, data); if (res < 0) opserr << "Bidirectional::sendSelf() - failed to send data\n"; return res; } int Bidirectional::recvSelf(int cTag, Channel &theChannel, FEM_ObjectBroker &theBroker) { int res = 0; static Vector data(10); res = theChannel.recvVector(this->getDbTag(), cTag, data); if (res < 0) { opserr << "Bidirectional::recvSelf() - failed to receive data\n"; E = 0; this->setTag(0); } else { this->setTag((int)data(0)); E = data(1); sigY = data(2); Hiso = data(3); Hkin = data(4); eP_n[0] = data(5); eP_n[1] = data(6); q_n[0] = data(7); q_n[1] = data(8); alpha_n = data(9); // Set the trial state variables revertToLastCommit(); } return res; } void Bidirectional::Print(OPS_Stream &s, int flag) { s << "Bidirectional, tag: " << this->getTag() << endln; s << "\tE: " << E << endln; s << "\tsigY: " << sigY<< endln; s << "\tHiso: " << Hiso << endln; s << "\tHkin: " << Hkin << endln; } Generated on Mon Oct 23 15:05:17 2006 for OpenSees by  1.5.0

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