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Optistruct HGEFFMASS

Altair Forum User

Hello,

In optisruct modal analysis after defining output->HGEFMASS .

it generate *.mass file output which gives us result plot modal eff mass(%) vs freq.

can you please tell how modal eff mass (%) file (*.mass) generated from modal eff mass.?

Thanks in advance

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Rahul Rajan_21763

Please refer below post which is similar to your query.Refer attached pdf for the equations.

https://community.altair.com/community?id=community_question&sys_id=8c5684b61b2bd0908017dc61ec4bcb3c

Unable to find an attachment - read this blog

Altair Forum User

Thanks for inputs Rahul..

i agreed .out write modal participation factor/ratio and modal eff mass/fraction according to PARAM equations.

i would like to know equation for modal eff mass percentage written in *.mass file.

Please revert.

Altair Forum User

Hi Ketan,

Meff mass is a ratio of coefficient vector square and normalized mass. How Coefficient vector is calculated is another story /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20'>

I would suggest you refer literature or textbooks for the same.