The Incrementation tab

When you configure general procedures, you use the Basic tab in the step editor to enter the total time period for the step. You use the Incrementation tab to configure the approach that Abaqus will use to divide the total time period for the step into increments. For a general, static step as well as for many other kinds of steps you can set the following options on the Incrementation tabbed page:

Related Topics
Understanding steps
Using the step editor
Time incrementation

  • When you choose Automatic time incrementation, Abaqus starts the incrementation using the value entered for the initial increment size. The size of subsequent time increments are adjusted based on how quickly the solution converges. This option is the default selection.

  • When you choose Fixed time incrementation, Abaqus uses the value entered for the initial increment size throughout the step.

    Warning:

    Choosing Fixed time incrementation may prevent the solution from converging and is not recommended.

Maximum number of increments

Abaqus limits the number of increments in a step to the value that you enter for the maximum number of increments. If the step exceeds this number of increments, the analysis stops, and diagnostic information is reported to the Job module and written to the message file. By default, Abaqus/CAE sets the maximum number of increments to 100.

Initial increment size

Abaqus starts the step using the value entered for the initial increment size.

Minimum increment size

Abaqus checks for the minimum increment size only when you analyze your model using automatic time incrementation. If Abaqus needs a smaller time increment than this value to reach a convergent solution, it terminates the analysis, reports to the Job module, and writes diagnostic information to the message file. If you do not enter a minimum increment size, Abaqus uses 10-5 times the total time period.

Maximum increment size

Abaqus checks for the maximum increment size only when you analyze your model using automatic time incrementation. Abaqus will not increase the increment size beyond this value during the analysis. If you do not specify this value, Abaqus/CAE sets the value to that of the total time period (with the exception of dynamic, implicit procedures, in which the default maximum increment size depends on a variety of analysis settings; see Configuring a dynamic, implicit procedure).

Note:

A value must be entered for each of the incrementation options described above. Abaqus/CAE does not allow you to create the step if you delete the default value for an incrementation option but fail to provide another.

For detailed information on other items in the Incrementation tabbed page, click HelpOn Context and then click the item of interest.