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CableMaterial.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: 1.7 $ // $Date: 2003/02/25 23:33:37 $ // $Source: /usr/local/cvs/OpenSees/SRC/material/uniaxial/CableMaterial.cpp,v $ // Written: Charles Chadwell // Created: 07/01 // // Description: This file contains the class definition for // CableMaterial. CableMaterial provides the abstraction // of an elastic uniaxial material, // // The input parameters are the Prestress, E, Effective Self Weight (gravity component of // Weight per volume transverse to the cable), and Length of the cable. // // The cable Force Displacement is converted to Stress Strain material for use // with the truss element. The stress strain ranges from slack (large strain at zero // stress) to taught (linear with modulus E). The material has no history and is not // path dependent. // // // What: "@(#) CableMaterial.cpp, revA" #include <CableMaterial.h> #include <Vector.h> #include <Channel.h> #include <Information.h> CableMaterial::CableMaterial(int tag, double PRESTRESS, double e, double UNIT_WEIGHT_EFF, double L_Element) :UniaxialMaterial(tag,MAT_TAG_CableMaterial), Ps(PRESTRESS), E(e), Mue(UNIT_WEIGHT_EFF), L(L_Element), trialStrain(0.0) { } CableMaterial::CableMaterial() :UniaxialMaterial(0,MAT_TAG_CableMaterial), Ps(0.0), E(0.0), Mue(0.0), L(0.0), trialStrain(0.0) { } CableMaterial::~CableMaterial() { // does nothing } int CableMaterial::setTrialStrain(double strain, double strainRate) { trialStrain = strain; double derivE, derivG, stress; // Check if out side the range of inportance double testStress, dP, curstrain, e0; int i = 0; // Perameters for bisection double L_bound = 0, U_bound, middle = 0; if (trialStrain < 0) U_bound = Ps; else { U_bound = E * trialStrain + Ps; testStress = U_bound; } // Check if slack in cable has been taken out and it is a bar e0 = Mue*Mue*L*L/(24*Ps*Ps) - Ps/E; if (trialStrain > 0 && abs(trialStrain - evalStress((trialStrain - e0)*E)) < 10e-9) trialStress = (trialStrain - e0)*E; // Check if all slack if (trialStrain < - Ps/E*10.0) trialStress = 0.0; // if stress is in between then do itterations -- Bisection dP = U_bound - L_bound; while (abs(dP)/U_bound > 0.00000001 && i < 100) { middle = .5 * (U_bound + L_bound); curstrain = evalStress(middle); if (curstrain <= trialStrain) { L_bound = middle; } else { U_bound = middle; } dP = U_bound - L_bound; i++; } // if it did not converge - return near zero stress if (i == 100) trialStress = 0.0; else trialStress = middle; if (stress <= 0.0) trialTangent = 0.0; // Elastic Part derivE = 1 / E * (1. - Mue * Mue * L * L / (24. * stress * stress) * (1. - 2. * Ps / stress)); // Geometric Part derivG = 1 / 12. * Mue * Mue * L * L / (stress * stress * stress); if (derivE + derivG != 0.0) trialTangent = 1.0 / (derivE + derivG); else trialTangent = 1e-8; return 0; } int CableMaterial::setTrial(double strain, double &stress, double &tangent, double strainRate) { this->setTrialStrain(strain, strainRate); // set the return values stress = trialStress; tangent = trialTangent; return 0; } double CableMaterial::getStress(void) { return trialStress; } double CableMaterial::evalStress(double stress) { double strainG, strainE; // Should never be zero or less than zero if (stress <= 0) {return -10;} // Elastic Part strainE = 1 / E * (stress - Ps) * (1 + Mue * Mue * L * L / (24 * stress)); // Geometric Part strainG = 1 / 24 * Mue * Mue * L * L * (1 / (Ps * Ps) - 1 / (stress * stress)); return strainE + strainG; } double CableMaterial::getTangent(void) { return trialTangent; }; int CableMaterial::commitState(void) { return 0; } int CableMaterial::revertToLastCommit(void) { return 0; } int CableMaterial::revertToStart(void) { trialStrain = 0.0; return 0; } UniaxialMaterial * CableMaterial::getCopy(void) { CableMaterial *theCopy = new CableMaterial(this->getTag(), Ps, E, Mue, L); theCopy->trialStrain = trialStrain; return theCopy; } int CableMaterial::sendSelf(int cTag, Channel &theChannel) { int res = 0; static Vector data(5); data(0) = this->getTag(); data(1) = Ps; data(2) = E; data(3) = Mue; data(4) = L; res = theChannel.sendVector(this->getDbTag(), cTag, data); if (res < 0) opserr << "CableMaterial::sendSelf() - failed to send data\n"; return res; } int CableMaterial::recvSelf(int cTag, Channel &theChannel, FEM_ObjectBroker &theBroker) { int res = 0; static Vector data(5); res = theChannel.recvVector(this->getDbTag(), cTag, data); if (res < 0) { opserr << "CableMaterial::recvSelf() - failed to receive data\n"; E = 0; this->setTag(0); return res; } this->setTag(data(0)); Ps = data(1); E = data(2); Mue = data(3); L = data(4); return res; } void CableMaterial::Print(OPS_Stream &s, int flag) { s << "CableMaterial tag: " << this->getTag() << endln; s << " E: " << E << " Prestress: " << Ps << endln; } //int //CableMaterial::setParameter(const char **argv, int argc, Information &info) //{ // if (strcmp(argv[0],"E") == 0) { // info.theType = DoubleType; // } // else if (strcmp(argv[0],"eta") == 0) { // info.theType = DoubleType; // return 2; // } // else // return -1; //} // //int //CableMaterial::updateParameter(int parameterID, Information &info) //{ // switch(parameterID) { // case -1: // return -1; // case 1: // E = info.theDouble; // return 0; // case 2: // eta = info.theDouble; // return 0; // default: // return -1; // } //} double CableMaterial::abs(double value) { if (value < 0) return -value; else return value; } Generated on Mon Oct 23 15:05:19 2006 for OpenSees by  1.5.0

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