In Workbench, a random vibration analysis needs to be preceeded by a modal analysis. If you have already inserted a random vibration analysis cell in your project page, you can follow these steps: 1. Return to your Workbench Project Page 2. In the cell that says “Random Vibration” on your project schematic, right mouse click the cell labeled “Random Vibration” (this will be cell number 1) 3. From the right mouse click menu, choose “Replace With” > Modal (ANSYS) 4. You should now see your cell labeled as “Modal (ANSYS) 5. Drag and Drop a “Random Vibration (ANSYS)” cell from the project schematic into the “Solution” cell of your Modal branch (this will be cell 6 on the Modal branch). When you return to your Mechanical window and set up boundary conditions in your Modal analysis environment, you should able to see those very boundary conditions available under your PSD load in the random vibration environment.