rayleigh command

srisri_iitk · Post by **srisri_iitk** » Sat May 12, 2007 10:25 pm

I am using rayleing damping for my model, so it has alpha and beta. But there there are other 2 parameters in rayleigh command and if i need constant damping ratio of 5% to all modes how can i define by this command.
rayleigh 0 0.05 0 0
is it ok?

silvia · Post by **silvia** » Sun May 13, 2007 12:21 pm

NO, these are the alpha and beta for mass and stiffness-proportional damping.
please look at the manual for the meaning of the 4 variables.

Ben-Peng · Post by **Ben-Peng** » Sun May 20, 2007 11:19 pm

i have the same question about this. i want to know how to define the 4 parameters that i want to set a constant damping ratio of 2%.
thanks!

silvia · Post by **silvia** » Mon May 21, 2007 5:49 am

you really only define two parameters, the M-prop and the K-prop values,
you just have to choose which of the three stiffnesses you use.
these parameters are discussed in any dynamics book, chopra's book has them.

Ben-Peng · Post by **Ben-Peng** » Mon May 21, 2007 7:29 am

Thanks silvia. I have got it!