Viscoelastic elastomers.
Viscoelastic elastomers.
(OP)
Hi all,
When dealing with rubbers, silicons and others, it's rather easy to find data's around shore and all the "elastic" properties of a given material.
The viscoelasticity of those materials is something I am interrested in to evaluate efficiency of vibration dampers and I did not find a lot of data's on that subject.
We builded in house a machine to evaluate this property on a given sample but, so far, silicon manufacturers we contacted , when they understand what you are talking about ,don't have much informations.
Any tips, books, or ideas on that subject will be welcomed.
Thanks,
HS
When dealing with rubbers, silicons and others, it's rather easy to find data's around shore and all the "elastic" properties of a given material.
The viscoelasticity of those materials is something I am interrested in to evaluate efficiency of vibration dampers and I did not find a lot of data's on that subject.
We builded in house a machine to evaluate this property on a given sample but, so far, silicon manufacturers we contacted , when they understand what you are talking about ,don't have much informations.
Any tips, books, or ideas on that subject will be welcomed.
Thanks,
HS





RE: Viscoelastic elastomers.
maybe I am misunderstanding your question?
Visco(sity) and elasticity are imho two sides of the same coin.
Any dynamic tests like torsion pendulum or forced vibrations give on the end a modulus of elasticity and a loss modulus and a loss angle (tan delta) describing their correlation.
Berti
RE: Viscoelastic elastomers.
I am a newbie in this area.
What I'd like to understand is in fact what is the rational approach when designing vibrations dampers using elastomers given constraints such as thickness Shore, expected absorbtion coefficient....
The Visco part as far as I understood is transforming vibs in heat
In our "home made" setup we've tested miscellaneous silicons & rubbers in various conditions
For our application
We want to get rid of vibrations in the range 150 --- 600 Hz
basically having a unit weighting 60 grammes
A 10dB attenuation would be fine and the max dimension of a layer is 3 mm x 50 x 50
we would like to optimize this; currently the best performer is a Nusil silicon that wasn't specially designed for that application but that we could test.
The manufacturer just provided samples of miscellaneous silicons, some of them worked others not.
This test approach will work but I was just wondering if a more rational approach could be found.
Cheers,
HS
RE: Viscoelastic elastomers.
If you need further help you may contact:
http://www.ViscoData.de
or read the relevant section of the book: "How to Design with rubbers" edited by A. Gent; Carl Hanser Publisher
Good Luck !
RE: Viscoelastic elastomers.
when designing polymers for dampening of noise and vibrations there is another factor which must be taken into account besides the viscoelastic properties: the density of the polymer. More mass absorbs more energy. This is usually accomplished in elastomers by adding heavy fillers.
Check out the density of the products you've tested as well.
Good Luck!
Roger
RE: Viscoelastic elastomers.
But you should know that really appropriate measurements of rubber's dynamic properties requires first-class knowledge of the methods and equipment.