Method newStep

SRC/analysis/integrator/DisplacementControl.cpp:191–296

}
 
   int
DisplacementControl::newStep(void)
{

  if (theDofID == -1) {
    opserr << "DisplacementControl::newStep() - dof is fixed or constrained (or domainChanged has not been called!)\n";
    return -1;
   }

   // get pointers to AnalysisModel and LinearSOE
   AnalysisModel *theModel = this->getAnalysisModel();
   LinearSOE *theLinSOE = this->getLinearSOE();    
   if (theModel == 0 || theLinSOE == 0) {
      opserr << "WARNING DisplacementControl::newStep() ";
      opserr << "No AnalysisModel or LinearSOE has been set\n";
      return -1;
   }

   if (theDomain == 0)
     theDomain = theModel->getDomainPtr();   
     
   // determine increment for this iteration
   double factor = double(specNumIncrStep)/numIncrLastStep;
   theIncrement *=factor;

   if (theIncrement < minIncrement)
      theIncrement = minIncrement;
   else if (theIncrement > maxIncrement)
      theIncrement = maxIncrement;


   // get the current load factor
   currentLambda = theModel->getCurrentDomainTime();

   // determine dUhat
   this->formTangent(tangFlag);
   theLinSOE->setB(*phat);
   if (theLinSOE->solve() < 0) {
      opserr << "DisplacementControl::newStep(void) - failed in solver\n";
      return -1;
   }

   (*deltaUhat) = theLinSOE->getX();
   Vector &dUhat = *deltaUhat;// this is the Uft in the nonlinear lecture notes
   double dUahat = dUhat(theDofID);// this is the component of the Uft in our nonlinear lecture notes

   if (dUahat == 0.0) {
      opserr << "WARNING DisplacementControl::newStep() ";
      opserr << "dUahat is zero -- zero reference displacement at control node DOF\n";
      return -1;
   }

   // determine delta lambda(1) == dlambda    
   double dlambda = theIncrement/dUahat; // this is the dlambda of the 1st step

  // calldLambda1dh=theIncrement;
   deltaLambdaStep = dlambda;
   currentLambda += dlambda;