3.2.6. integrator Command

This command is used to construct the Integrator object.

The Integrator object is used for the following:

1. determine the predictive step for time t+dt, \(\Delta U\) in static analysis, \(\Delta U\), \(\Delta \dot U\), and \(\Delta \ddot U\) in a transient analysis.

2. specify the tangent matrix and residual vector at any iteration, i.e. what constitutes the \(A\) matrix and \(b\) vector in \(Ax=b\).

3. determine the corrective step based on the x vector, i.e. given \(x\) what is \(\Delta U\) in static analysis, \(\Delta U\), \(\Delta \dot U\), and \(\Delta \ddot U\) in a transient analysis.

numberer numbererType? arg1? ...

Argument	Type	Description
$numbererType	string	the numberer type
$args	list	a list of arguments for that type

The type of integrator used in the analysis is dependent on whether it is a static analysis or transient analysis. The following contain information about numbererType? and the args required for each of the available integrator types:

Static Integrators:

• 3.2.6.1. LoadControl Command
• 3.2.6.2. DisplacementControl Command
• 3.2.6.3. MinimumUnbalancedDisplacementNorm
• 3.2.6.4. Arc-Length Control

Transient Integrators:

• 3.2.6.5. Central Difference
• 3.2.6.6. Newmark Method
• 3.2.6.7. Hilber-Hughes-Taylor Method
• 3.2.6.8. Generalized Alpha Method
• 3.2.6.9. TRBDF2
• 3.2.6.10. Explicit Difference

Utility Integrators:

• 3.2.6.11. GimmeMCK Command

Code developed by: fmk