To add a time history load definition

To add a time history load definition to your physical model, use the following procedure.

On the Catalog ribbon tab, select the Add Time History tool in the Load Definitions group.

The Create: Time History load definition dialog opens.
Type a Name to identify the time history definition.
(Optional) Check the Save option to save the time history data to a separate file during analysis.
Select the Curve Type to use for this time history load.
Select the Data point source to use for this time history load The corresponding data or function parameters are displayed.

Depending on the option selected in Step 5, either:

Choice	Action
Custom	Type time and action pairs in the Custom source group by clicking in the Acceleration / Force / Moment data field.
External	Click in the External source group to navigate to the plain text or spreadsheet file containing time history data
Polynomial	Type the polynomial function constants and time data.
Trigonometric	Type the trigonometric function constants and rime data.
Harmonic	Type the harmonic function constants and time data.

Click OK.

The time history definition is added to the model catalog.

To use a time history load, you must next add a Time History Ground Motion and add Time History nodal loads to that group.

Selecting a time history definition in the catalog will display its parameters in the Properties panel.

You can edit a time history load definition by selecting it from the structure catalog and then clicking the Edit tool in the Edit group on the Catalog ribbon tab.