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ViscousMaterial.cpp

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00001 /* ****************************************************************** **
00002 **    OpenSees - Open System for Earthquake Engineering Simulation    **
00003 **          Pacific Earthquake Engineering Research Center            **
00004 **                                                                    **
00005 **                                                                    **
00006 ** (C) Copyright 1999, The Regents of the University of California    **
00007 ** All Rights Reserved.                                               **
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00013 **                                                                    **
00014 ** Developed by:                                                      **
00015 **   Frank McKenna (fmckenna@ce.berkeley.edu)                         **
00016 **   Gregory L. Fenves (fenves@ce.berkeley.edu)                       **
00017 **   Filip C. Filippou (filippou@ce.berkeley.edu)                     **
00018 **                                                                    **
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00020                                                                         
00021 // $Revision: 1.5 $
00022 // $Date: 2003/04/02 22:02:42 $
00023 // $Source: /usr/local/cvs/OpenSees/SRC/material/uniaxial/ViscousMaterial.cpp,v $
00024                                                                         
00025 // Written: Mehrdad Sasani 
00026 // Created: June 2000
00027 // Revision: A
00028 //
00029 // Description: This file contains the class implementation for 
00030 // ViscousMaterial. 
00031 
00032 #include <math.h>
00033 
00034 #include <ViscousMaterial.h>
00035 #include <Vector.h>
00036 #include <Channel.h>
00037 
00038 #include <OPS_Globals.h>
00039 
00040 ViscousMaterial::ViscousMaterial(int tag, double c, double a)
00041 :UniaxialMaterial(tag,MAT_TAG_Viscous),
00042  trialRate(0.0), C(c), Alpha(a)
00043 {
00044     if (Alpha < 0.0) {
00045       opserr << "ViscousMaterial::ViscousMaterial -- Alpha < 0.0, setting to 1.0\n";
00046       Alpha = 1.0;
00047     }
00048 }
00049 
00050 ViscousMaterial::ViscousMaterial()
00051 :UniaxialMaterial(0,MAT_TAG_Viscous),
00052  trialRate(0.0), C(0.0), Alpha(0.0)
00053 {
00054 
00055 }
00056 
00057 ViscousMaterial::~ViscousMaterial()
00058 {
00059   // does nothing
00060 }
00061 
00062 int 
00063 ViscousMaterial::setTrialStrain(double strain, double strainRate)
00064 {
00065     trialRate = strainRate;
00066 
00067     return 0;
00068 }
00069 
00070 double 
00071 ViscousMaterial::getStress(void)
00072 {
00073     double stress = C*pow(fabs(trialRate),Alpha);
00074 
00075     if (trialRate < 0.0)
00076         return -stress;
00077     else
00078         return  stress;
00079 }
00080 
00081 double 
00082 ViscousMaterial::getTangent(void)
00083 {
00084     return 0.0;
00085 }
00086 
00087 double 
00088 ViscousMaterial::getInitialTangent(void)
00089 {
00090     return 0.0;
00091 }
00092 
00093 double
00094 ViscousMaterial::getDampTangent(void)
00095 {
00096   static const double minvel = 1.e-11;
00097 
00098     double absRate = fabs(trialRate);
00099 
00100     if (absRate < minvel)
00101                 return Alpha*C*pow(minvel,Alpha-1.0);
00102         else
00103                 return Alpha*C*pow(absRate,Alpha-1.0);  
00104 }
00105 
00106 
00107 double 
00108 ViscousMaterial::getStrain(void)
00109 {
00110     return 0.0;
00111 }
00112 
00113 double 
00114 ViscousMaterial::getStrainRate(void)
00115 {
00116     return trialRate;
00117 }
00118 
00119 int 
00120 ViscousMaterial::commitState(void)
00121 {
00122     return 0;
00123 }
00124 
00125 int 
00126 ViscousMaterial::revertToLastCommit(void)
00127 {
00128     return 0;
00129 }
00130 
00131 int 
00132 ViscousMaterial::revertToStart(void)
00133 {
00134     trialRate = 0.0;
00135 
00136     return 0;
00137 }
00138 
00139 UniaxialMaterial *
00140 ViscousMaterial::getCopy(void)
00141 {
00142     ViscousMaterial *theCopy = new ViscousMaterial(this->getTag(),C,Alpha);
00143 
00144     theCopy->trialRate = trialRate;
00145 
00146     return theCopy;
00147 }
00148 
00149 int 
00150 ViscousMaterial::sendSelf(int cTag, Channel &theChannel)
00151 {
00152   int res = 0;
00153   static Vector data(4);
00154   data(0) = this->getTag();
00155   data(1) = C;
00156   data(2) = Alpha;
00157   data(3) = trialRate;
00158   res = theChannel.sendVector(this->getDbTag(), cTag, data);
00159   if (res < 0) 
00160     opserr << "ViscousMaterial::sendSelf() - failed to send data\n";
00161 
00162   return res;
00163 }
00164 
00165 int 
00166 ViscousMaterial::recvSelf(int cTag, Channel &theChannel, 
00167                                FEM_ObjectBroker &theBroker)
00168 {
00169   int res = 0;
00170   static Vector data(4);
00171   res = theChannel.recvVector(this->getDbTag(), cTag, data);
00172   
00173   if (res < 0) {
00174       opserr << "ViscousMaterial::recvSelf() - failed to receive data\n";
00175       C = 0; 
00176       this->setTag(0);      
00177   }
00178   else {
00179     this->setTag((int)data(0));
00180     C = data(1);
00181         Alpha = data(2);
00182     trialRate = data(3);
00183   }
00184     
00185   return res;
00186 }
00187 
00188 void 
00189 ViscousMaterial::Print(OPS_Stream &s, int flag)
00190 {
00191     s << "Viscous tag: " << this->getTag() << endln;
00192     s << "  C: " << C << endln;
00193     s << "  Alpha: " << Alpha << endln;
00194 }
00195 
00196

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