eigenvalues reactor

Amine A · Dec 1, 2022

Hello,
I'm doing some tutorials to learn how to simulate a seismic response of a reactor. I modeled at first the reactor and did the static and modal analysis and it gives me as eigenvalues 10Hz , 14Hz, 20Hz,... 68Hz. Then Iwanted to integrate the basemat of superstructure and eigen values become 3Hz; 3,24Hz;...;4Hz. I attached a picture of the model. Can anyone please tell me why eigenvalues has changed like that , Thank you

not_a_pro · Dec 2, 2022

Hi Anime A,
this depends on a lot of factors. It would be helpfull to have some further information like the boundary conditions of the besement, the mass of it and the stiffness in comparison to the reactor.
For example, when the stiffness is much lower than the reactor stiffness, which would make sense I think, the eigenvalues would decrease as seen.
Can you also upload some pictures of the first few eigenforms?

Amine A · Dec 2, 2022

hHi,
Thanks, I've put a bigger mass for the basemat (and tried a lot of values to see if it can change the result, but I still have the same...). Here you can find some pictures of the first few eigenforms

Amine A · Dec 2, 2022

Amine A · Dec 2, 2022

Amine A · Dec 2, 2022

Amine A · Dec 2, 2022

Amine A · Dec 2, 2022

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

eigenvalues reactor

Amine A

Mechanical

Recommended for you

not_a_pro

Student

Amine A

Mechanical

Amine A

Mechanical

Amine A

Mechanical

Amine A

Mechanical

Amine A

Mechanical

Amine A

Mechanical

Similar threads

Part and Inventory Search

Sponsor