Dynamic Random Analysis
A dynamic random analysis measures the system’s response to stationary, random loads of known power spectral density (PSD).
For a description of, and requirements for a dynamic random analysis see Dynamic Random Analysis Overview.
The Dynamic Random Analysis dialog box includes the following:
• Loading—Select Load Functions or Base Excitation.
◦ Load Functions—To use Load Functions, you must have loads defined 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—Allows you to select 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 PSD—Specifies the direction of motion of the supports and power spectral density of the base acceleration when you select Base Excitation as the loading type.
For a dynamic random analysis the following tabs appear on the dynamic random analysis dialog box:
• Modes
• Output