To define arrival times and damping used for time
history loads, use the following procedure.
You must first
define a time history type by one of the previously described methods.
One set of time history parameters
can be defined for your model for all time history load types.
-
On the Loading ribbon tab, select the
tool in the
Dynamic Specifications group.
The
Define Param dialog opens.
- Optional:
Check the
Time Step option and type the time step value.
This is the solution time step used in step-by-step integration
of the uncoupled equations. If not selected, the default value of 0.0013888
seconds is used.
-
Select the
Damping Type to use and, if explicit
Damping is selected, type the damping ratio to
be used for all modes.
-
Type in one or more
Arrival Times for the dynamic loads.
Arrival time is the time at which a load type begins to act at a
joint (forcing function) or at the base of the structure (ground motion).
-
Click
Add.
The time history
load parameters are added to the
Time History Definitions in the
Load & Definition dialog.
In order to use a time history load
definition, you must add a time history load item to a primary load case.