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Steel03.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: 1.4 $ // $Date: 2006/05/24 21:44:31 $ // $Source: /usr/local/cvs/OpenSees/SRC/material/uniaxial/Steel03.cpp,v $ // Written: mackie // Created: 06/2005 // Revision: A // // Description: This file contains the class implementation for // Steel03. Steel03 is Steel01 verbatim but with added Giuffre-Menegotto-Pinto // transitions on the loading and unloading loops. // references: // 1.) Menegotto, M., and Pinto, P.E. (1973). Method of analysis of cyclically loaded // RC plane frames including changes in geometry and non-elastic behavior of // elements under normal force and bending. Preliminary Report IABSE, vol 13. // 2.) Dhakal, R.J., and Maekawa, K. (2002). Path-dependent cyclic stress-strain relationship // of reinforcing bar including buckling. Engineering Structures, 24(11): 1383-96. // 3.) Gomes, A., and Appleton, J. (1997). Nonlinear cyclic stress-strain relationship of // reinforcing bars including buckling. Engineering Structures, 19(10): 822-6. // // What: "@(#) Steel03.C, revA" #include <Steel03.h> #include <Vector.h> #include <Matrix.h> #include <Channel.h> #include <Information.h> #include <math.h> #include <float.h> //uniaxialMaterial Steel02 $matTag $Fy $E $b $R0 $cR1 $cR2 $a1 $a2 $a3 $a4 Steel03::Steel03 (int tag, double FY, double E, double B, double R, double R1, double R2, double A1, double A2, double A3, double A4): UniaxialMaterial(tag,MAT_TAG_Steel03), fy(FY), E0(E), b(B), r(R), cR1(R1), cR2(R2), a1(A1), a2(A2), a3(A3), a4(A4) { // Sets all history and state variables to initial values // History variables CminStrain = 0.0; CmaxStrain = 0.0; CshiftP = 1.0; CshiftN = 1.0; Cloading = 0; CbStrain = 0.0; CbStress = 0.0; CrStrain = 0.0; CrStress = 0.0; Cplastic = 0.0; TminStrain = 0.0; TmaxStrain = 0.0; TshiftP = 1.0; TshiftN = 1.0; Tloading = 0; TbStrain = 0.0; TbStress = 0.0; TrStrain = 0.0; TrStress = 0.0; Tplastic = 0.0; // State variables Cstrain = 0.0; Cstress = 0.0; Ctangent = E0; CcurR = getR(0); Tstrain = 0.0; Tstress = 0.0; Ttangent = E0; TcurR = getR(0); } Steel03::Steel03():UniaxialMaterial(0,MAT_TAG_Steel03), fy(0.0), E0(0.0), b(0.0), r(0.0), cR1(0.0), cR2(0.0), a1(0.0), a2(0.0), a3(0.0), a4(0.0) { } Steel03::~Steel03 () { } int Steel03::setTrialStrain (double strain, double strainRate) { // Reset history variables to last converged state TminStrain = CminStrain; TmaxStrain = CmaxStrain; TshiftP = CshiftP; TshiftN = CshiftN; Tloading = Cloading; TbStrain = CbStrain; TbStress = CbStress; TrStrain = CrStrain; TrStress = CrStress; Tplastic = Cplastic; TcurR = CcurR; // Determine change in strain from last converged state double dStrain = strain - Cstrain; if (fabs(dStrain) > DBL_EPSILON) { // Set trial strain Tstrain = strain; // Calculate the trial state given the trial strain determineTrialState (dStrain); } return 0; } int Steel03::setTrial (double strain, double &stress, double &tangent, double strainRate) { // Reset history variables to last converged state TminStrain = CminStrain; TmaxStrain = CmaxStrain; TshiftP = CshiftP; TshiftN = CshiftN; Tloading = Cloading; TbStrain = CbStrain; TbStress = CbStress; TrStrain = CrStrain; TrStress = CrStress; Tplastic = Cplastic; TcurR = CcurR; // Determine change in strain from last converged state double dStrain = strain - Cstrain; if (fabs(dStrain) > DBL_EPSILON) { // Set trial strain Tstrain = strain; // Calculate the trial state given the trial strain determineTrialState (dStrain); } stress = Tstress; tangent = Ttangent; return 0; } double Steel03::getR (double x_in) { // maybe modify this later, but it gives us better degradation at smaller strains x_in = fabs(x_in); double temp_r = r; // new input parameters are supposed to match Steel02 which look like // Dhakal and Maekawa values: cr1 = 0.925, cr2 = 0.15 // where 0.925 comes from 18.5/20.0 where R0=20 and 18.5 is the old coefficient provided // // so for old Dhakal and Maekawa R0 = 20, cr1 = 18.5/R0 = 0.925, cr2 = 0.15 // so for old Gomes and Appleton R0 = 20, cr1 = 19.0/R0 = 0.95, cR2 = 0.3 // so for my old model, now just use R0 = 20, cR1 = 0, cR2 = 0 if (cR1 < 0.1 && cR2 < 0.1) { // Mackie, rough trilinear fit to the tangent to the x_in-r first // quadrant circle. Try using with values of R0 like 20 to 30 temp_r = r*2.0/20.0; double t1 = -x_in/7+15/7*temp_r; double t2 = -4*x_in+6*temp_r; if (t1 > temp_r) temp_r = t1; if (t2 > temp_r) temp_r = t2; //opserr << "xin = " << x_in << " rout = " << temp_r << endln; } else { temp_r = r * (1.0 - cR1*x_in/(cR2+x_in)); if (temp_r < 0) temp_r = 1.0e-8; } return temp_r; } void Steel03::determineTrialState (double dStrain) { double fyOneMinusB = fy * (1.0 - b); double Esh = b*E0; double epsy = fy/E0; double c1 = Esh*Tstrain; double c2 = TshiftN*fyOneMinusB; double c3 = TshiftP*fyOneMinusB; double c = Cstress + E0*dStrain; // // Determine if a load reversal has occurred due to the trial strain // // Determine initial loading condition if (Tloading == 0 && dStrain != 0.0) { TmaxStrain = epsy; TminStrain = -epsy; if (dStrain > 0.0) { Tloading = 1; TbStrain = TmaxStrain; TbStress = fy; Tplastic = TmaxStrain; } else { Tloading = -1; TbStrain = TminStrain; TbStress = -fy; Tplastic = TminStrain; } double intval = 1+pow(fabs(Tstrain/epsy),TcurR); Tstress = c1+(1-b)*E0*Tstrain/pow(intval,1/TcurR); Ttangent = Esh+E0*(1-b)/pow(intval,1+1/TcurR); } // Transition from loading to unloading, i.e. positive strain increment // to negative strain increment if (Tloading == 1 && dStrain < 0.0) { Tloading = -1; if (Cstrain > TmaxStrain) TmaxStrain = Cstrain; Tplastic = TminStrain; TshiftN = 1 + a1*pow((TmaxStrain-TminStrain)/(2.0*a2*epsy),0.8); TrStrain = Cstrain; TrStress = Cstress; TbStrain = (c2+c)/E0/(b-1)+Tstrain/(1-b); TbStress = 1/(b-1)*(b*c2+b*c-c1)-c2; TcurR = getR((TbStrain-TminStrain)/epsy); } // Transition from unloading to loading, i.e. negative strain increment // to positive strain increment if (Tloading == -1 && dStrain > 0.0) { Tloading = 1; if (Cstrain < TminStrain) TminStrain = Cstrain; Tplastic = TmaxStrain; TshiftP = 1 + a3*pow((TmaxStrain-TminStrain)/(2.0*a4*epsy),0.8); TrStrain = Cstrain; TrStress = Cstress; TbStrain = (c3-c)/E0/(1-b)+Tstrain/(1-b); TbStress = 1/(1-b)*(b*c3-b*c+c1)+c3; TcurR = getR((TmaxStrain-TbStrain)/epsy); } if (Cloading != 0) { double c4 = TbStrain - TrStrain; double c5 = TbStress - TrStress; double c6 = Tstrain - TrStrain; double c4c5 = c5/c4; double intval = 1+pow(fabs(c6/c4),TcurR); Tstress = TrStress+b*c4c5*c6+(1-b)*c4c5*c6/pow(intval,1/TcurR); Ttangent = c4c5*b+c4c5*(1-b)/pow(intval,1+1/TcurR); } } double Steel03::getStrain () { return Tstrain; } double Steel03::getStress () { return Tstress; } double Steel03::getTangent () { return Ttangent; } int Steel03::commitState () { // History variables CminStrain = TminStrain; CmaxStrain = TmaxStrain; CshiftP = TshiftP; CshiftN = TshiftN; Cloading = Tloading; CbStrain = TbStrain; CbStress = TbStress; CrStrain = TrStrain; CrStress = TrStress; Cplastic = Tplastic; CcurR = TcurR; // State variables Cstrain = Tstrain; Cstress = Tstress; Ctangent = Ttangent; return 0; } int Steel03::revertToLastCommit () { // Reset trial history variables to last committed state TminStrain = CminStrain; TmaxStrain = CmaxStrain; TshiftP = CshiftP; TshiftN = CshiftN; Tloading = Cloading; TbStrain = CbStrain; TbStress = CbStress; TrStrain = CrStrain; TrStress = CrStress; Tplastic = Cplastic; // Reset trial state variables to last committed state Tstrain = Cstrain; Tstress = Cstress; Ttangent = Ctangent; TcurR = CcurR; return 0; } int Steel03::revertToStart () { // History variables CminStrain = 0.0; CmaxStrain = 0.0; CshiftP = 1.0; CshiftN = 1.0; Cloading = 0; CbStrain = 0.0; CbStress = 0.0; CrStrain = 0.0; CrStress = 0.0; Cplastic = 0.0; TminStrain = 0.0; TmaxStrain = 0.0; TshiftP = 1.0; TshiftN = 1.0; Tloading = 0; TbStrain = 0.0; TbStress = 0.0; TrStrain = 0.0; TrStress = 0.0; Tplastic = 0.0; // State variables Cstrain = 0.0; Cstress = 0.0; Ctangent = E0; CcurR = getR(0); Tstrain = 0.0; Tstress = 0.0; Ttangent = E0; TcurR = getR(0); return 0; } UniaxialMaterial* Steel03::getCopy () { Steel03* theCopy = new Steel03(this->getTag(), fy, E0, b, r, cR1, cR2, a1, a2, a3, a4); // Converged history variables theCopy->CminStrain = CminStrain; theCopy->CmaxStrain = CmaxStrain; theCopy->CshiftP = CshiftP; theCopy->CshiftN = CshiftN; theCopy->Cloading = Cloading; theCopy->CbStrain = CbStrain; theCopy->CbStress = CbStress; theCopy->CrStrain = CrStrain; theCopy->CrStress = CrStress; theCopy->Cplastic = Cplastic; // Trial history variables theCopy->TminStrain = TminStrain; theCopy->TmaxStrain = TmaxStrain; theCopy->TshiftP = TshiftP; theCopy->TshiftN = TshiftN; theCopy->Tloading = Tloading; theCopy->TbStrain = TbStrain; theCopy->TbStress = TbStress; theCopy->TrStrain = TrStrain; theCopy->TrStress = TrStress; theCopy->Tplastic = Tplastic; // Converged state variables theCopy->Cstrain = Cstrain; theCopy->Cstress = Cstress; theCopy->Ctangent = Ctangent; theCopy->CcurR = CcurR; // Trial state variables theCopy->Tstrain = Tstrain; theCopy->Tstress = Tstress; theCopy->Ttangent = Ttangent; theCopy->TcurR = TcurR; return theCopy; } int Steel03::sendSelf (int commitTag, Channel& theChannel) { int res = 0; static Vector data(25); data(0) = this->getTag(); // Material properties data(1) = fy; data(2) = E0; data(3) = b; data(4) = r; data(5) = cR1; data(6) = cR2; data(7) = a1; data(8) = a2; data(9) = a3; data(10) = a4; // History variables from last converged state data(11) = CminStrain; data(12) = CmaxStrain; data(13) = CshiftP; data(14) = CshiftN; data(15) = Cloading; data(16) = CbStrain; data(17) = CbStress; data(18) = CrStrain; data(19) = CrStress; data(20) = Cplastic; // State variables from last converged state data(21) = Cstrain; data(22) = Cstress; data(23) = Ctangent; data(24) = CcurR; // Data is only sent after convergence, so no trial variables // need to be sent through data vector res = theChannel.sendVector(this->getDbTag(), commitTag, data); if (res < 0) opserr << "Steel03::sendSelf() - failed to send data\n"; return res; } int Steel03::recvSelf (int commitTag, Channel& theChannel, FEM_ObjectBroker& theBroker) { int res = 0; static Vector data(25); res = theChannel.recvVector(this->getDbTag(), commitTag, data); if (res < 0) { opserr << "Steel03::recvSelf() - failed to receive data\n"; this->setTag(0); } else { this->setTag(int(data(0))); // Material properties fy = data(1); E0 = data(2); b = data(3); r = data(4); cR1 = data(5); cR2 = data(6); a1 = data(7); a2 = data(8); a3 = data(9); a4 = data(10); // History variables from last converged state CminStrain = data(11); CmaxStrain = data(12); CshiftP = data(13); CshiftN = data(14); Cloading = int(data(15)); CbStrain = data(16); CbStress = data(17); CrStrain = data(18); CrStress = data(19); Cplastic = data(20); // Copy converged history values into trial values since data is only // sent (received) after convergence TminStrain = CminStrain; TmaxStrain = CmaxStrain; TshiftP = CshiftP; TshiftN = CshiftN; Tloading = Cloading; TbStrain = CbStrain; TbStress = CbStress; TrStrain = CrStrain; TrStress = CrStress; Tplastic = Cplastic; // State variables from last converged state Cstrain = data(21); Cstress = data(22); Ctangent = data(23); CcurR = data(24); // Copy converged state values into trial values Tstrain = Cstrain; Tstress = Cstress; Ttangent = Ctangent; TcurR = CcurR; } return res; } void Steel03::Print (OPS_Stream& s, int flag) { s << "Steel03 tag: " << this->getTag() << endln; s << " fy: " << fy << " "; s << " E0: " << E0 << " "; s << " b: " << b << " "; s << " r: " << r << " cR1: " << cR1 << " cR2: " << cR2 << endln; s << " a1: " << a1 << " "; s << " a2: " << a2 << " "; s << " a3: " << a3 << " "; s << " a4: " << a4 << " "; } Generated on Mon Oct 23 15:05:22 2006 for OpenSees by  1.5.0

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