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Concrete02.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: 1.1 $ // $Date: 2006/03/03 18:52:40 $ // $Source: /usr/local/cvs/OpenSees/SRC/material/uniaxial/Concrete02.cpp,v $ // Written: fmk // Created: 03/06 // // Description: This file contains the class implementation of Concrete02. // This Concrete02 is based on an f2c of the FEDEAS material // Concr2.f which is: //----------------------------------------------------------------------- // concrete model with damage modulus // by MOHD YASSIN (1993) // adapted to FEDEAS material library // by D. Sze and Filip C. Filippou in 1994 //----------------------------------------------------------------------- #include <stdlib.h> #include <Concrete02.h> #include <OPS_Globals.h> #include <float.h> #include <Channel.h> Concrete02::Concrete02(int tag, double _fc, double _epsc0, double _fcu, double _epscu, double _rat, double _ft, double _Ets): UniaxialMaterial(tag, MAT_TAG_Concrete02), fc(_fc), epsc0(_epsc0), fcu(_fcu), epscu(_epscu), rat(_rat), ft(_ft), Ets(_Ets) { ecminP = 0.0; deptP = 0.0; eP = 2.0*fc/epsc0; epsP = 0.0; sigP = 0.0; eps = 0.0; sig = 0.0; e = 2.0*fc/epsc0; } Concrete02::Concrete02(void): UniaxialMaterial(0, MAT_TAG_Concrete02) { } Concrete02::~Concrete02(void) { // Does nothing } UniaxialMaterial* Concrete02::getCopy(void) { Concrete02 *theCopy = new Concrete02(this->getTag(), fc, epsc0, fcu, epscu, rat, ft, Ets); return theCopy; } double Concrete02::getInitialTangent(void) { return 2.0*fc/epsc0; } int Concrete02::setTrialStrain(double trialStrain, double strainRate) { double ec0 = fc * 2. / epsc0; // retrieve concrete hitory variables ecmin = ecminP; dept = deptP; // calculate current strain eps = trialStrain; double deps = eps - epsP; // if the current strain is less than the smallest previous strain // call the monotonic envelope in compression and reset minimum strain if (eps < ecmin) { this->Compr_Envlp(eps, sig, e); ecmin = eps; } else {; // else, if the current strain is between the minimum strain and ept // (which corresponds to zero stress) the material is in the unloading- // reloading branch and the stress remains between sigmin and sigmax // calculate strain-stress coordinates of point R that determines // the reloading slope according to Fig.2.11 in EERC Report // (corresponding equations are 2.31 and 2.32 // the strain of point R is epsR and the stress is sigmR double epsr = (fcu - rat * ec0 * epscu) / (ec0 * (1.0 - rat)); double sigmr = ec0 * epsr; // calculate the previous minimum stress sigmm from the minimum // previous strain ecmin and the monotonic envelope in compression double sigmm; double dumy; this->Compr_Envlp(ecmin, sigmm, dumy); // calculate current reloading slope Er (Eq. 2.35 in EERC Report) // calculate the intersection of the current reloading slope Er // with the zero stress axis (variable ept) (Eq. 2.36 in EERC Report) double er = (sigmm - sigmr) / (ecmin - epsr); double ept = ecmin - sigmm / er; if (eps <= ept) { double sigmin = sigmm + er * (eps - ecmin); double sigmax = er * .5f * (eps - ept); sig = sigP + ec0 * deps; e = ec0; if (sig <= sigmin) { sig = sigmin; e = er; } if (sig >= sigmax) { sig = sigmax; e = 0.5 * er; } } else { // else, if the current strain is between ept and epn // (which corresponds to maximum remaining tensile strength) // the response corresponds to the reloading branch in tension // Since it is not saved, calculate the maximum remaining tensile // strength sicn (Eq. 2.43 in EERC Report) // calculate first the strain at the peak of the tensile stress-strain // relation epn (Eq. 2.42 in EERC Report) double epn = ept + dept; double sicn; if (eps <= epn) { this->Tens_Envlp(dept, sicn, e); if (dept != 0.0) { e = sicn / dept; } else { e = ec0; } sig = e * (eps - ept); } else { // else, if the current strain is larger than epn the response // corresponds to the tensile envelope curve shifted by ept double epstmp = eps - ept; this->Tens_Envlp(epstmp, sig, e); dept = eps - ept; } } } return 0; } double Concrete02::getStrain(void) { return eps; } double Concrete02::getStress(void) { return sig; } double Concrete02::getTangent(void) { return e; } int Concrete02::commitState(void) { ecminP = ecmin; deptP = dept; eP = e; sigP = sig; epsP = eps; return 0; } int Concrete02::revertToLastCommit(void) { ecmin = ecminP;; dept = deptP; e = eP; sig = sigP; eps = epsP; return 0; } int Concrete02::revertToStart(void) { ecminP = 0.0; deptP = 0.0; eP = 2.0*fc/epsc0; epsP = 0.0; sigP = 0.0; eps = 0.0; sig = 0.0; e = 2.0*fc/epsc0; return 0; } int Concrete02::sendSelf(int commitTag, Channel &theChannel) { static Vector data(13); data(0) =fc; data(1) =epsc0; data(2) =fcu; data(3) =epscu; data(4) =rat; data(5) =ft; data(6) =Ets; data(7) =ecminP; data(8) =deptP; data(9) =epsP; data(10) =sigP; data(11) =eP; data(12) = this->getTag(); if (theChannel.sendVector(this->getDbTag(), commitTag, data) < 0) { opserr << "Concrete02::sendSelf() - failed to sendSelf\n"; return -1; } return 0; } int Concrete02::recvSelf(int commitTag, Channel &theChannel, FEM_ObjectBroker &theBroker) { static Vector data(13); if (theChannel.sendVector(this->getDbTag(), commitTag, data) < 0) { opserr << "Concrete02::recvSelf() - failed to recvSelf\n"; return -1; } fc = data(0); epsc0 = data(1); fcu = data(2); epscu = data(3); rat = data(4); ft = data(5); Ets = data(6); ecminP = data(7); deptP = data(8); epsP = data(9); sigP = data(10); eP = data(11); this->setTag(data(12)); e = eP; sig = sigP; eps = epsP; return 0; } void Concrete02::Print(OPS_Stream &s, int flag) { s << "Concrete02:(strain, stress, tangent) " << eps << " " << sig << " " << e << endln; } void Concrete02::Tens_Envlp (double epsc, double &sigc, double &Ect) { /*----------------------------------------------------------------------- ! monotonic envelope of concrete in tension (positive envelope) ! ! ft = concrete tensile strength ! Ec0 = initial tangent modulus of concrete ! Ets = tension softening modulus ! eps = strain ! ! returned variables ! sigc = stress corresponding to eps ! Ect = tangent concrete modulus !-----------------------------------------------------------------------*/ double Ec0 = 2.0*fc/epsc0; double eps0 = ft/Ec0; double epsu = ft*(1.0/Ets+1.0/Ec0); if (epsc<=eps0) { sigc = epsc*Ec0; Ect = Ec0; } else { if (epsc<=epsu) { Ect = -Ets; sigc = ft-Ets*(epsc-eps0); } else { // Ect = 0.0 Ect = 1.0e-10; sigc = 0.0; } } return; } void Concrete02::Compr_Envlp (double epsc, double &sigc, double &Ect) { /*----------------------------------------------------------------------- ! monotonic envelope of concrete in compression (negative envelope) ! ! fc = concrete compressive strength ! epsc0 = strain at concrete compressive strength ! fcu = stress at ultimate (crushing) strain ! epscu = ultimate (crushing) strain ! Ec0 = initial concrete tangent modulus ! epsc = strain ! ! returned variables ! sigc = current stress ! Ect = tangent concrete modulus -----------------------------------------------------------------------*/ double Ec0 = 2.0*fc/epsc0; double ratLocal = epsc/epsc0; if (epsc>=epsc0) { sigc = fc*ratLocal*(2.0-ratLocal); Ect = Ec0*(1.0-ratLocal); } else { // linear descending branch between epsc0 and epscu if (epsc>epscu) { sigc = (fcu-fc)*(epsc-epsc0)/(epscu-epsc0)+fc; Ect = (fcu-fc)/(epscu-epsc0); } else { // flat friction branch for strains larger than epscu sigc = fcu; Ect = 1.0e-10; // Ect = 0.0 } } return; } Generated on Mon Oct 23 15:05:19 2006 for OpenSees by  1.5.0

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