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Message 1 of 6
oyvinkle
352 Views, 5 Replies

Mass eccentricetis

I have run a modal analysis with the consistent mass matrix using the mass matrix offest with 5% and add modal masses with 5% and an anallysis with noe eccssentriseties. how come the offset mass matrix results are so different??

 

 

5 REPLIES 5
Message 2 of 6
oyvinkle
in reply to: oyvinkle

wrote wrong on the pic. the nodal and matrix ar mixed up!

Message 3 of 6
Rafal.Gaweda
in reply to: oyvinkle

Recomended to use Nodal eccenticities.



Rafal Gaweda
Message 4 of 6
Rafal.Gaweda
in reply to: Rafal.Gaweda

Small explanation:

 

Adding to nodes -that's clear, masses are added \ moved from nodes to other nodes


Offseting mass matrix - whole mass matrix is shifted; by "kind of" rigid links it is linked with previous state and additionally small "rotation" of this matrix (masses) may appear because of "rigid links" so it is less phisical approach than shifting by adding masses to nodes.



Rafal Gaweda
Message 5 of 6
oyvinkle
in reply to: Rafal.Gaweda

How come?

Message 6 of 6
Rafal.Gaweda
in reply to: oyvinkle

???????????



Rafal Gaweda

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