rayleigh damping instead of visco-el material?

[stawrogin]

Hi

I have to model rubber in a direct time integration analysis where the internal material damping of the rubber at high frequencies should be modelled as well. I would prefer to use the Rayleigh damping to estimate these damping effects in the structure than setting up a visco-elastic material model. I found some specific damping ratios and would estimate the coefficients alpha and better for the Rayleigh damping. However I suppose in principle it should work, I’m not sure if this correct and which effects are neglected by the use of the Rayleigh damping instead of a visco-elastic material model. Has anybody experience with such problems or can anybody give some references how modelled these damping effects?

Thanks in advance

stawrogin

 

[ParaDoc]

...well, at least to my knowledge, if time integration is involved, you should rely on the so called "internal variable" approach of viscoelasticity. Here, the characteristic relaxation time constants of the given rubber governs the appropriate differential equations which have to be solved by time integration in order to get the response-function of the problem.

Details of this approach may be found on the web-site:

http://www.ViscoData.de

and / or contact me at
machenba@parker.com

good luck !!!