time for other load steps. To start your analysis at "zero" time, such as in a transient analysis, specify a
very small value such as TIME,1E-6.
2.6.1.3. Number of Substeps and Time Step Size
For a nonlinear or transient analysis, you need to specify the number of substeps to be taken within a
load step. This is done as follows:
Command(s):DELTIM
GUI: Main Menu> Preprocessor> Loads> Load Step Opts> Time/Frequenc> Time & Time Step
Main Menu> Solution> Load Step Opts> Sol'n Control ( : Basic Tab)
Main Menu> Solution> Load Step Opts> Time/Frequenc> Time & Time Step
Main Menu> Solution> Load Step Opts> Time/Frequenc> Time & Time Step
Command(s):NSUBST
GUI: Main Menu> Preprocessor> Loads> Load Step Opts> Time/Frequenc> Freq & Substeps (or
Time and Substps)
Main Menu> Solution> Load Step Opts> Sol'n Control ( : Basic Tab)
Main Menu> Solution> Load Step Opts> Time/Frequenc> Freq & Substeps (or Time and Substps)
Main Menu> Solution> Unabridged Menu> Time/Frequenc> Freq & Substeps (or Time and Substps)
NSUBST specifies the number of substeps, and DELTIM specifies the time step size. By default, the
program uses one substep per load step.
2.6.1.4. Automatic Time Stepping
The AUTOTS command activates automatic time stepping. Its equivalent GUI paths are:
GUI:
Main Menu> Preprocessor> Loads> Load Step Opts> Time/Frequenc> Time & Time
Step (or Time and Substps)
Main Menu> Solution> Load Step Opts> Sol'n Control ( : Basic Tab)
Main Menu> Solution> Load Step Opts> Time/Frequenc> Time & Time Step (or Time
and Substps)
Main Menu> Solution> Load Step Opts> Time/Frequenc> Time & Time Step (or Time
and Substps)In automatic time stepping, the program calculates an optimum time step at the end of each substep,
based on the response of the structure or component to the applied loads. When used in a nonlinear
static (or steady-state) analysis,AUTOTS determine the size of load increments between substeps.
2.6.1.5. Stepping or Ramping Loads
When specifying multiple substeps within a load step, you need to indicat e whether the loads are to
be ramped or stepped. The KBC command is used for this purpose:KBC,0 indicat es ramped loads, and
KBC,1 indicat es stepped loads. The default depends on the discipline and type of analysis.
Command(s):KBC
GUI: Main Menu> Solution> Load Step Opts> Sol'n Control ( : Transient Tab)
Main Menu> Solution> Load Step Opts> Time/Frequenc> Freq & Substeps (or Time and Substps or Time
& Time Step)
Main Menu> Solution> Load Step Opts> Time/Frequenc> Freq & Substeps (or Time and Substps or Time
& Time Step)
Some notes about stepped and ramped loads are:
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