Learning Forum

[Matthew Caballero]

I have a harmonic response analysis setup and it is using the Mode Superposition method. The model runs fine, but for some reason the program will not let me add a frequency response solution for reaction forces unless I change 'Expand Results From --> Harmonic Solution' to 'Expand Results From --> Modal Solution'. Aside from the bolts reactions, the model runs fine with either setting. 

Is anyone able to explain the logic behind why 'Harmonic Solution' expansion will not give me bolt reactions? Or what the difference is between expand using 'harmonic solution' vs 'modal solution'?

[Zoi Stavrothanasi]

Hello Matthew,

When using Mode-Superposition (MSUP) Harmonic Response in a non-linear Pre-stress environment the only available option to expand the results from is a Modal Solution. 

 

Hope this helps!

Zoi

[Matthew Caballero]

Hi Zoi. There is no pre-stress. The program gives me the option to toggle between expanding from "harmonic solution" and expanding from "modal solution". Either way works just fine, except when extracting reaction forces. When extracting reaction forces, I have to select "expand from modal solution."