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FatigueMaterial.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: 2006/08/18 23:00:31 $ // $Source: /usr/local/cvs/OpenSees/SRC/material/uniaxial/FatigueMaterial.cpp,v $ // Written: Patxi // Created: Aug 2003 // // Description: This file contains the class definition for // FatigueMaterial. FatigueMaterial wraps a UniaxialMaterial // and imposes fatigue limits. More information about this material can // be found in the doctoral dissertation of Patxi Uriz: // // Uriz, Patxi, "Towards Earthquake Resistant Design of // Concentrically Braced Steel Frames," Ph.D. Dissertation, // Structural Engineering, Mechanics, and Materials, Civil // and Envrironmental Engineering, University of California, // Berkeley, December 2005 // // Modifications to the code have been added by Kevin Mackie, Ph.D., as // shown below. #include <stdlib.h> #include <MaterialResponse.h> #include <Information.h> #include <FatigueMaterial.h> #include <ID.h> #include <Channel.h> #include <FEM_ObjectBroker.h> #include <OPS_Globals.h> #include <OPS_Stream.h> FatigueMaterial::FatigueMaterial(int tag, UniaxialMaterial &material, double dmax, double E_0, double slope_m, double epsmin, double epsmax ) :UniaxialMaterial(tag,MAT_TAG_Fatigue), theMaterial(0), Cfailed(false), trialStrain(0) { DI = 0; //Damage index X = 0; //Range in consideration Y = 0; //Previous Adjacent Range A = 0; //Peak or valley 1 B = 0; //Peak or valley 2 C = 0; //Peak or valley 2 D = 0; //Peak or valley 4 PCC = 0; /*Previous Cycle counter flag if >1 then previous 'n' cycles did not flag a complete cycle */ R1F = 0; //Flag for first peak count R2F = 0; //Flag for second peak count CS = 0; //Current Slope PS = 0; //Previous slope EP = 0; //Previous Strain SF = 0; /*Start Flag = 0 if very first strain, (i.e. when initializing) = 1 otherwise */ DL = 0; //Damage if current strain was last peak. // added 6/9/2006 SR1 = 0; NC1= 0; SR2 = 0; NC2 = 0; SR3 = 0; NC3 = 0; if ( dmax > 1.0 || dmax < 0.0 ) { opserr << "FatigueMaterial::FatigueMaterial " << "- Dmax must be between 0 and 1, assuming Dmax = 1\n" ; Dmax = 1; } else Dmax = dmax; E0 = E_0; m = slope_m; minStrain = epsmin; maxStrain = epsmax; theMaterial = material.getCopy(); if (theMaterial == 0) { opserr << "FatigueMaterial::FatigueMaterial " << " -- failed to get copy of material\n" ; exit(-1); } } FatigueMaterial::FatigueMaterial() :UniaxialMaterial(0,MAT_TAG_Fatigue), theMaterial(0), Cfailed(false), trialStrain(0) { DI = 0; //Damage index X = 0; //Range in consideration Y = 0; //Previous Adjacent Range A = 0; //Peak or valley 1 B = 0; //Peak or valley 2 C = 0; //Peak or valley 2 D = 0; //Peak or valley 4 PCC = 0; /*Previous Cycle counter flag if >1 then previous 'n' cycles did not flag a complete cycle */ R1F = 0; //Flag for first peak count R2F = 0; //Flag for second peak count CS = 0; //Current Slope PS = 0; //Previous slope EP = 0; //Previous Strain SF = 0; /*Start Flag = 0 if very first strain, (i.e. when initializing) = 1 otherwise */ DL = 0; //Damage if current strain was last peak. Dmax = 0; E0 = 0; m = 0; minStrain = 0; maxStrain = 0; // added 6/9/2006 SR1 = 0; NC1 = 0; SR2 = 0; NC2 = 0; SR3 = 0; NC3 = 0; } FatigueMaterial::~FatigueMaterial() { if (theMaterial) delete theMaterial; } static int sign(double a) { if (a < 0) return -1; else if (a == 0) return 0; else return 1; } int FatigueMaterial::setTrialStrain(double strain, double strainRate) { if (Cfailed) { trialStrain = strain; // return 0; return theMaterial->setTrialStrain(strain, strainRate); } else { Cfailed = false; trialStrain = strain; return theMaterial->setTrialStrain(strain, strainRate); } } double FatigueMaterial::getStress(void) { double modifier = 1.0; double damageloc = 1.0-Dmax+DL; if (Cfailed) // Reduce stress to 0.0 return theMaterial->getStress()*1.0e-8; /* // This portion of the code was added by Kevin Mackie, Ph.D. // This is appropriate for steel material. Uncomment to use. else if ( damageloc <= 0.9 ) modifier = 1.0-725.0/2937.0*pow(damageloc,2); else modifier = 8.0*(1.0-damageloc); if (modifier <= 0) modifier = 1.0e-8; else return theMaterial->getStress()*modifier; */ else return theMaterial -> getStress(); } double FatigueMaterial::getTangent(void) { double modifier = 1.0; double damageloc = 1.0-Dmax+DL; if (Cfailed) // Reduce tangent to 0.0 return 1.0e-8*theMaterial->getInitialTangent(); /* // This portion of the code was added by Kevin Mackie, Ph.D. // This is appropriate for steel material. Uncomment to use. else if ( damageloc <= 0.9 ) modifier = 1.0-725.0/2937.0*pow(damageloc,2); else modifier = 8.0*(1.0-damageloc); if (modifier <= 0) // modifier = 1.0e-8; modifier = 1.0e-3; */ else return theMaterial->getTangent()*modifier; } double FatigueMaterial::getDampTangent(void) { if (Cfailed) return 0.0; else return theMaterial->getDampTangent(); } double FatigueMaterial::getStrain(void) { return theMaterial->getStrain(); } double FatigueMaterial::getStrainRate(void) { return theMaterial->getStrainRate(); } int FatigueMaterial::commitState(void) { // NOTE: Do not accumulate damage if peaks are too small (e.g. if X < 1e-10) // may get floating point errors. This is essentially a filter for // strain cycles smaller than 1e-10 strain. // THIS FATIGE MATERIAL CODE WAS NOT INTENDED FOR HIGH CYCLE FATIGUE, // THE LINEAR ACCUMULATION OF DAMAGE IS NOT AS APPROPRIATE FOR HIGH // CYCLE FATIGUE. //added 6/9/2006 // for recorder SR1 = 0; NC1 = 0; // No need to continue if the uniaxial material copy // has already failed. if (Cfailed) { return 0; } //Simple check to see if we reached max strain capacities if (trialStrain >= maxStrain || trialStrain <= minStrain) { Cfailed = true; opserr << "FatigueMaterial: material tag " << this->getTag() << " failed from excessive strain\n"; DI = Dmax; DL = Dmax; return 0; } //Initialize the fatigue parameters if they have // not been initialized yet if (SF == 0) { A = trialStrain; SF = 1 ; EP = trialStrain; // Initialize other params if not done so already PCC = 0; B = 0; C = 0; D = 0; } /* Now we need to determine if we are at a peak or not If we are, then we need to do some calcs to determine the amount of damage suffered. If we are not at a peak, we need to pretend like we are at a peak, so that we can calculate the damage as if it WERE a peak. */ // Determine the slope of the strain hysteresis if ( EP == trialStrain ) { CS = PS; // No real slope here.... } else { CS = trialStrain - EP; // Determine Current Slope } // If we are at a peak or a valley, then check for damage if (sign(PS) != sign(CS) && sign(PS) != 0 ) { if ( R1F == 0 ) { // mark second peak B = EP; Y = fabs(B-A); R1F = 1; } else { // start at least the third peak // begin modified Rainflow cycle counting if (PCC == 1) { D = EP; X = fabs(D-C); } else { C = EP; X = fabs(C-B); } if (X < Y) { PCC = PCC + 1; if (PCC == 1) { Y = fabs(C-B); } else if (PCC == 2 ) { // Count X = |D-C| as a 1.0 cycle DI = DI + 1.0 / fabs(pow( (X/E0) , 1/m )) ; //added 6/9/2006 SR1 = X; NC1 = 1.0; // Reset parameters D = 0; C = 0; Y = fabs(B-A); PCC = 0; } } else { if (PCC == 1 ) { // Count Y = |C-B| as a 1.0 cycle DI = DI + 1.0 / fabs(pow( (Y/E0) , 1/m )); //added 6/9/2006 SR1 = Y; NC1 = 1.0; // Reset parameters B = D; C = 0; D = 0; Y = fabs(B-A); PCC = 0; } else { // Count Y = |A-B| as a 0.5 cycle DI = DI + 0.5 / fabs(pow( (Y/E0), 1/m )); //added 6/9/2006 // For recorder SR1 = Y; NC1 = 0.5; // Reset parameters A = B; B = C; C = 0; D = 0; Y = X; PCC = 0; } } } // Flag failure if we have reached that point if (DI >= Dmax ) { // Most likely will not fail at this point, more // likely at the psuedo peak. But this step is // is important for accumulating damage Cfailed = true; opserr << "FatigueMaterial: material tag " << this->getTag() << " failed at peak\n"; DL=DI; } else { Cfailed = false; DL=DI; } // Modified by Patxi 3/5/2006 // } else { } if (Cfailed == false) { // Now check for damage, although we may not be at a peak at all. // Store temporary damage only as if it were the last peak: DL // Commit to DI only if failure occurs. if (B == 0 && C == 0 && D == 0) { // If we have not yet found the second peak X = fabs(trialStrain - A); if (fabs(X) < 1e-10) { DL = DI ; // added 6/9/2006 //values for recorder SR2 = 0.0; NC2 = 0.0; SR3 = 0.0; NC3 = 0.0; } else { DL = DI + 0.5 / fabs(pow( (X/E0), 1/m )); // added 6/9/2006 //values for recorder SR2 = X; NC2 = 0.5; SR3 = 0.0; NC3 = 0.0; } } else if (B != 0 && C == 0 && D == 0) { // On our way to find point C. Range Y defined, no X yet X = fabs(trialStrain - B); if (fabs(X) < 1e-10) { DL = DI; // added 6/9/2006 //values for recorder SR2 = 0.0; NC2 = 0.0; } else { DL = DI + 0.5 / fabs(pow( (X/E0) , 1/m )); // added 6/9/2006 //values for recorder SR2 = X; NC2 = 0.5; } if (fabs(Y) < 1e-10) { DL = DL; // added 6/9/2006 //values for recorder SR3 = 0.0; NC3 = 0.0; } else { DL = DL + 0.5 / fabs(pow( (Y/E0) , 1/m )); // added 6/9/2006 //values for recorder SR3 = Y; NC3 = 0.5; } } else if (B != 0 && C != 0 && D == 0) { // Two ranges stored, but no cycles for either stored // There are two scenarios that can result: // 1.) |A-D| is the predominate 1/2 cycle, // and |B-C| is a small full cycle. // // 2.) One full cylce at |D-C|, 1/2 cycle at |A-B| if (fabs(A-trialStrain)> fabs(A-B)) { // count 1/2 cycle at |D-A|, and one full cycle at |B-C|. X = fabs(trialStrain-A); if (fabs(Y) < 1e-10) { DL = DI; // added 6/9/2006 //values for recorder SR3 = 0.0; NC3 = 0.0; } else { DL = DI + 1.0 / fabs(pow( (Y/E0) , 1/m )); // added 6/9/2006 //values for recorder SR3 = Y; NC3 = 1.0; } if (fabs(X) < 1e-10) { DL = DL; // added 6/9/2006 //values for recorder SR2 = 0.0; NC2 = 0.0; } else { DL = DL + 0.5 / fabs(pow( (X/E0) , 1/m )); // added 6/9/2006 //values for recorder SR2 = X; NC2 = 0.5; } } else { // One full cycle of |C-D| and 1/2 cyle of |A-B| if (fabs(C-trialStrain) < 1e-10) { DL = DI; // added 6/9/2006 //values for recorder SR3 = 0.0; NC3 = 0.0; } else { DL = DI + 1.0 / fabs(pow( ( fabs(C-trialStrain)/E0 ) , 1/m )); // added 6/9/2006 //values for recorder SR3 = fabs(C-trialStrain); NC3 = 1.0; } if (fabs(A-B) < 1e-10) { DL = DL; // added 6/9/2006 //values for recorder SR2 = 0.0; NC2 = 0.0; } else { DL = DL + 0.5 / fabs(pow( (fabs(A-B) /E0) , 1/m )); // added 6/9/2006 //values for recorder SR2 = fabs(A-B); NC2 = 0.5; } } } // Did we fail before a peak? double mStress = theMaterial->getStress(); if (DL > Dmax && mStress > 0.0 ) { DI = DL; Cfailed = true; opserr << "FatigueMaterial: material tag " << this->getTag() << " failed at pseudo peak\n"; } else { Cfailed = false; } } PS = CS; // Previous Slope EP = trialStrain; // Keep track of previous strain // Check if failed at current step if (Cfailed) { return 0; } else return theMaterial->commitState(); } int FatigueMaterial::revertToLastCommit(void) { // Check if failed at last step if (Cfailed) return 0; else return theMaterial->revertToLastCommit(); } // Kevin Mackie, Ph.D. is responsible for the addition of // revertToStart, sendSelf, recvSelf. Thanks to Kevin for making this // code more user friendly! int FatigueMaterial::revertToStart(void) { Cfailed = false; DI = 0; //Damage index X = 0; //Range in consideration Y = 0; //Previous Adjacent Range A = 0; //Peak or valley 1 B = 0; //Peak or valley 2 C = 0; //Peak or valley 2 D = 0; //Peak or valley 4 PCC = 0; /*Previous Cycle counter flag if >1 then previous 'n' cycles did not flag a complete cycle */ R1F = 0; //Flag for first peak count R2F = 0; //Flag for second peak count CS = 0; //Current Slope PS = 0; //Previous slope EP = 0; //Previous Strain SF = 0; /*Start Flag = 0 if very first strain, (i.e. when initializing) = 1 otherwise */ DL = 0; //Damage if current strain was last peak. Dmax = 0; E0 = 0; m = 0; minStrain = 0; maxStrain = 0; // added 6/9/2006 //values for recorder SR1 = 0; NC1 = 0; SR2 = 0; NC2 = 0; SR3 = 0; NC3 = 0; return theMaterial->revertToStart(); } UniaxialMaterial * FatigueMaterial::getCopy(void) { FatigueMaterial *theCopy = new FatigueMaterial(this->getTag(), *theMaterial, Dmax, E0, m ,minStrain, maxStrain); theCopy->Cfailed = Cfailed; theCopy->trialStrain = trialStrain; return theCopy; } int FatigueMaterial::sendSelf(int cTag, Channel &theChannel) { int dbTag = this->getDbTag(); static ID dataID(3); dataID(0) = this->getTag(); dataID(1) = theMaterial->getClassTag(); int matDbTag = theMaterial->getDbTag(); if ( matDbTag == 0) { matDbTag = theChannel.getDbTag(); theMaterial->setDbTag(matDbTag); } dataID(2) = matDbTag; if (theChannel.sendID(dbTag, cTag, dataID) < 0) { opserr << "FatigueMaterial::sendSelf() - failed to send the ID\n"; return -1; } static Vector dataVec(21); dataVec(0) = DI; dataVec(1) = X; dataVec(2) = Y; dataVec(3) = A; dataVec(4) = B; dataVec(5) = C; dataVec(6) = D; dataVec(7) = PCC; dataVec(8) = R1F; dataVec(9) = R2F; dataVec(10) = CS; dataVec(11) = PS; dataVec(12) = EP; dataVec(13) = SF; dataVec(14) = DL; dataVec(15) = Dmax; dataVec(16) = E0; dataVec(17) = m; dataVec(18) = minStrain; dataVec(19) = maxStrain; if (Cfailed == true) dataVec(20) = 1.0; else dataVec(20) = 0.0; if (theChannel.sendVector(dbTag, cTag, dataVec) < 0) { opserr << "FatigueMaterial::sendSelf() - failed to send the Vector\n"; return -2; } if (theMaterial->sendSelf(cTag, theChannel) < 0) { opserr << "FatigueMaterial::sendSelf() - failed to send the Material\n"; return -3; } return 0; } int FatigueMaterial::recvSelf(int cTag, Channel &theChannel, FEM_ObjectBroker &theBroker) { int dbTag = this->getDbTag(); static ID dataID(3); if (theChannel.recvID(dbTag, cTag, dataID) < 0) { opserr << "FatigueMaterial::recvSelf() - failed to get the ID\n"; return -1; } this->setTag(int(dataID(0))); // as no way to change material, don't have to check classTag of the material if (theMaterial == 0) { int matClassTag = int(dataID(1)); theMaterial = theBroker.getNewUniaxialMaterial(matClassTag); if (theMaterial == 0) { opserr << "FatigueMaterial::recvSelf() - failed to create Material with classTag " << dataID(0) << endln; return -2; } } theMaterial->setDbTag(dataID(2)); static Vector dataVec(21); if (theChannel.recvVector(dbTag, cTag, dataVec) < 0) { opserr << "FatigueMaterial::recvSelf() - failed to get the Vector\n"; return -3; } DI = dataVec(0); X = dataVec(1); Y = dataVec(2); A = dataVec(3); B = dataVec(4); C = dataVec(5); D = dataVec(6); PCC = int(dataVec(7)); R1F = int(dataVec(8)); R2F = int(dataVec(9)); CS = dataVec(10); PS = dataVec(11); EP = dataVec(12); SF = int(dataVec(13)); DL = dataVec(14); Dmax = dataVec(15); E0 = dataVec(16); m = dataVec(17); minStrain = dataVec(18); maxStrain = dataVec(19); if (dataVec(20) == 1.0) Cfailed = true; else Cfailed = false; if (theMaterial->recvSelf(cTag, theChannel, theBroker) < 0) { opserr << "FatigueMaterial::recvSelf() - failed to get the Material\n"; return -4; } return 0; } //Printing of current damage. NOTE: The damage that is returned // is damage at the psuedo peak, DL, ( if not at a peak when the // print function is called). The generic print will print both // the damage recorded at the last peak, along with current damage void FatigueMaterial::Print(OPS_Stream &s, int flag) { if (flag == 100) { s << DL << endln; } else { s << "FatigueMaterial tag: " << this->getTag() << endln; s << "\tMaterial: " << theMaterial->getTag() << endln; s << "\tDI: " << DI << " Dmax: " << Dmax << endln; s << "\tE0: " << E0 << " m: " << m << endln; s << "\tDL: " << DL << endln; } } Response* FatigueMaterial::setResponse(const char **argv, int argc, Information &matInfo, OPS_Stream &theOutput) { if (argc == 0) return 0; Response *theResponse = 0; theOutput.tag("UniaxialMaterialOutput"); theOutput.attr("matType", this->getClassType()); theOutput.attr("matTag", this->getTag()); // stress if (strcmp(argv[0],"stress") == 0) { theOutput.tag("ResponseType", "sigma11"); theResponse = new MaterialResponse(this, 1, this->getStress()); } // tangent else if (strcmp(argv[0],"tangent") == 0) { theOutput.tag("ResponseType", "C11"); theResponse = new MaterialResponse(this, 2, this->getTangent()); } // strain else if (strcmp(argv[0],"strain") == 0) { theOutput.tag("ResponseType", "eps11"); theResponse = new MaterialResponse(this, 3, this->getStrain()); } // strain else if ((strcmp(argv[0],"stressStrain") == 0) || (strcmp(argv[0],"stressANDstrain") == 0)) { theOutput.tag("ResponseType", "sig11"); theOutput.tag("ResponseType", "eps11"); theResponse = new MaterialResponse(this, 4, Vector(2)); } // damage else if (strcmp(argv[0],"damage") == 0) { theResponse = new MaterialResponse(this, 5, DI); theOutput.tag("ResponseType", "DI"); // added 6/9/2006 } else if (strcmp(argv[0],"cyclesAndRange") == 0) { theOutput.tag("ResponseType", "UnknownResponse"); theOutput.tag("ResponseType", "UnknownResponse"); theOutput.tag("ResponseType", "UnknownResponse"); theOutput.tag("ResponseType", "UnknownResponse"); theOutput.tag("ResponseType", "UnknownResponse"); theOutput.tag("ResponseType", "UnknownResponse"); theResponse = new MaterialResponse(this, 6, Vector(6)); } // end add theOutput.endTag(); return theResponse; } int FatigueMaterial::getResponse(int responseID, Information &matInfo) { static Vector stressStrain(2); static Vector cyclesAndRange(6); // each subclass must implement its own stuff switch (responseID) { case 1: matInfo.setDouble(this->getStress()); return 0; case 2: matInfo.setDouble(this->getTangent()); return 0; case 3: matInfo.setDouble(this->getStrain()); return 0; case 4: stressStrain(0) = this->getStress(); stressStrain(1) = this->getStrain(); matInfo.setVector(stressStrain); return 0; case 5: matInfo.setDouble(DI); return 0; case 6: cyclesAndRange(0) = NC1; cyclesAndRange(1) = SR1; cyclesAndRange(2) = NC2; cyclesAndRange(3) = SR2; cyclesAndRange(4) = NC3; cyclesAndRange(5) = SR3; matInfo.setVector(cyclesAndRange); return 0; default: return -1; } } Generated on Mon Oct 23 15:05:20 2006 for OpenSees by  1.5.0

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