Load Control - OpenSeesWiki

Load Control

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This command is used to construct a LoadControl integrator object.

integrator LoadControl $lambda <$numIter $minLambda $maxLambda>

$lambda the load factor increment λ
$numIter the number of iterations the user would like to occur in the solution algorithm. Optional, default = 1.0.
$minLambda the min stepsize the user will allow. optional, defualt = λmin = λ
$maxLambda the max stepsize the user will allow. optional, default = λmax = λ

NOTES:

  1. The change in applied loads that this causes depends on the active load patterns (those load patterns not set constant) and the loads in the load patterns. If the only active loads acting on the domain are in load patterns with a Linear time series with a factor of 1.0, this integrator is the same as the classical load control method.
  2. The optional arguments are supplied to speed up the step size in cases where convergence is too fast and slow down the step size in cases where convergence is too slow.

EXAMPLE:


integrator LoadControl 0.1;



THEORY:

In Load Control the time in the domain is set to t + λt + 1 where,

 \lambda_{t+1} = \max \left ( \lambda_{min},  \min \left ( \lambda_{max},  \frac{\text{numIter}}{\text{lastNumIter}} \lambda_{t} \right ) \right )



Code Developed by: fmk

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