Spectrum Analysis in ANSYS
After untyring efforts i was able to do modal analysis and i am happy that alot people are helping at this forum. Now the problem i am facing is that after modal analysis i am carrying our spectrum analysis. I have selected PSD as my spectrum analysis. I have all the statistical data of PSD table i.e Frequency Vs PSD. After entring the PSD table i have to apply the boundary conditions. I use following path to for Boundary Conditions.
Main Menu>>Preprocessor>>loads>>Define loads>>apply>>structural>>spectrum
Now here i have two options
1. Base PSD Excitation
2. NODE PSD Excitation
As far as i know that base PSD excit is used for displacement, acceleration and stress and node PSD is used for forces calculation. I want to use Base PSD excit for my problem. Now in Base PSD two options are available i.e
1. on key points
2. On nodes
Since my modle is 3D box so its very difficult to select the nodes beacuse my it contains thousands of nodes now how can i select the nodes of interest. I want to apply PSD at the bottom side of my block. Now how can i select the nodes?? Since i have imported the modle from Pro-E so very few keypoints are labled.
Kindly guide me how to select the nodes??