How to do modal analysis with damping of material?

[enjoywithme]

I want to obtain the modal damping with material damping input....looking forward help....

 

[juzz]

Hello!

You could use as method for extraction
DAMPED or QR DAMPED

Best wishes,
Juzz

-------------------------------
Justin Onisoru
Researcher
Romanian Academy
Institute of Solid Mechanics
-------------------------------

 

[enjoywithme]

Thanks the answer from Justin Onisoru.
I have tried the DAMPED and QR DAMPED method. But the result is so strange, I got no any complex frequency.
I paste the operations here...
--------------------------------
/PREP7
!*
ET,1,SHELL63
!*
!*
R,1,4e-3,4e-3,4e-3,4e-3, , ,
RMORE, , , ,
RMORE
RMORE, ,
!*
!*
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,EX,1,,1e9
MPDATA,PRXY,1,,0.3
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,DENS,1,,1.5e3
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,DAMP,1,,0.009
RECTNG,0,0.5,0,0.5,
!*
LESIZE,ALL, , ,20, ,1, , ,1,
amesh,all
FINISH
/SOLU
!*
ANTYPE,2
!*
MODOPT,DAMP,30
EQSLV,FRONT
MXPAND,30, , ,0
LUMPM,0
PSTRES,0
!*
MODOPT,DAMP,30,5,5000, ,OFF
/STATUS,SOLU
SOLVE
--------------------

 

[juzz]

Hello, enjoywithme!

I run your input and it seems to work pretty well.
I obtain 30 frequencies (not all are complex) but it's ok.
So, this is my advice:

1) At the beginning of your input add a command that redirect your output to a file:

/output,file_name,extension,path (default to current directory),mode_of_writting (overwriting or append)

but /output,output,out will be enough

List this file and you will see the frequencies (preceding participation factors calculus)

2) Ifyou don't want to write the output in a file when you open "Results summary..." under /post1 you will see that every substep appears twice. First is the real part, second is the imaginary part.

Best wishes,

Juzz
-------------------------------
Justin Onisoru
Researcher
Romanian Academy
Institute of Solid Mechanics
-------------------------------