- Define a dynamic load case by multiplying static load cases already entered by time functions, which should be defined as a Normal type in the "Time History Functions".
- This function is used to reflect the effect of the self-weight in the time history analysis due to seismic loads.
- First, define the self-weight using a Time Forcing Function and then assign the Time History Load Case for the self-weight. Next, define a Time History Load Case for the seismic load, selecting the previously defined self-weight time history load case as "Subsequent to Load Case" under "Order in Sequential Loading". Then perform analysis. This will ensure that when performing seismic analysis considering the self-weight; the self-weight is applied first, and then the seismic load is applied to the structure while maintaining the effect of the self-weight.
From the main menu, select [Load] tab > [Type : Dynamic Loads] > [Time History Analysis Data] group > [Time Varying static Loads]
Time History Load Case Name
Select a time history analysis load case entered in "Time History Load Cases". Click the ... button to define the relevant function if the load case has not been previously defined.
Select a static load case to be used as a dynamic load case.
Use the time history functions to multiply the static load cases and create a dynamic load case.
The values of the functions are unit-less. The type must be "Normal".
Function Name : Select the time history function defined in "Time Forcing Function".
In previous versions, only Ramp load type could be selected, but in the current version, any type of load defined in the Time Forcing Function can be chosen. However, it is important to note that the previously entered Ramp load values were converted to 0 and 1, whereas in the current version, the values entered in the Time Forcing Function are not converted and are input as they are. Therefore, for the same model, different results may be obtained between the versions due to this difference in handling the load values.
Arrival Time : "Delay" time for the time load function. Enter the delay time when the time varying static load is applied some time after the time history analysis is initiated.
Scale Factor : Scale factor for the time load function. This Scale Factor is independent of the Scale Factor which is entered in the Time History Function. You should exercise caution that the Scale Factors are not duplicated. Duplicating the input will multiply the Scale Factors.
Add : To add to previously entered time forcing functions at specific nodes.
Modify : To replace previously entered time forcing functions at specific nodes.
Delete : To delete previously entered time forcing functions at specific nodes.