about damping

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zhangchuanchao
Posts: 29
Joined: Wed Oct 15, 2008 2:01 am
Location: china

about damping

Post by zhangchuanchao »

hello silvia
My structure is one story two bay
I do not know whethethe its damping is same to the cantilever column
Can I use it the following? please tell me , thank you!
set xDamp 0.02; # 2% damping ratio
set lambda [eigen 1]; # eigenvalue mode 1
set omega [expr pow($lambda,0.5)];
set alphaM 0.; # M-prop. damping; D = alphaM*M
set betaKcurr 0.; # K-proportional damping; +beatKcurr*KCurrent
set betaKcomm [expr 2.*$xDamp/($omega)]; # K-prop. damping parameter; +betaKcomm*KlastCommitt
set betaKinit 0.; # initial-stiffness proportional damping +beatKinit*Kini
# define damping
rayleigh $alphaM $betaKcurr $betaKinit $betaKcomm;
# RAYLEIGH damping
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
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Post by silvia »

look at a dynamics text for the theoretical clacs.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
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