Dynamic Frequency Analysis
You can use a dynamic frequency analysis to evaluate the system’s periodic response to cyclical loads of frequency-dependent amplitude.
For a description of, and requirements of a dynamic frequency analysis see Dynamic Frequency Analysis Overview.
The Dynamic Frequency Analysis dialog box includes the following items:
• Loading—Select Load Functions or Base Excitation.
◦ Load Functions—To use Load Functions, you must have defined loads in your model. If you select Load Functions, the following items are displayed under Loading:
▪ Sum Load Sets—Combines the effects of the selected load sets into a single load set.
▪ Load Set / Component—Specifies the load sets you want to use in your analysis. Click 
to create load set functions for each load set or use the default functions.
to create load set functions for each load set or use the default functions.◦ Base Excitation—You can use Base Excitation only if you reference a constrained modal analysis in your dynamic analysis.
Base Acceleration Frequency Dependence—Specifies the direction of motion of the supports and the amplitude and phase of the base acceleration as functions of frequency if you select Base Excitation as the loading type.
For a dynamic frequency analysis the following tabs appear on the dynamic frequency analysis dialog box:
• Modes
• Output