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9.2.2 Time Settings
These settings control the time step controller. The solution can be progressed using fixed time steps or adaptive time steps, depending on whether you check the use auto time stepper option. When checked, it activates the auto timestep controller which will adapt the step size based on convergence information. The following parameters control the auto time step controller
- Timesteps: define the number of time steps to solve for. If the auto timestep controller is activated, this is merely a suggestion. The actual number of timesteps taken will vary based on the parameters below.
- Step size: defines the initial timestep size that will be taken by the time controller. If auto timestep controller is activated, the actual time step size taken will vary based on the parameters below. The product of the “Timesteps” parameter and the “Stepsize” parameter determines the termination time.
- Max retries: the maximum number of times that a particular timestep will be retried.
- Optimal iterations: The expected average number of iterations required to converged a single time step.
- Min step: the minimum stepsize that may be taken by the auto timestep controller.
- Max step: the maximum stepsize that may be taken by the auto time step controller. If a must point curve is specified this value will be overridden by the value of this curve.
- Cutback: select the method for reducing the step size if an iteration fails.
The use must-points option allows to use so-called must-points. The must-points are time points, defined through a load curve, for which the solution will be forced to pass through. The must point curve is edited in the Curve Editor. The value of the must point curve defines the maximum time step size that can be taken up to that point. If a must point curve is defined, the Max step value in the Project Settings is ignored.