Now, in the real world there are constraints. If you supply a hint or two about
reasonable responses can be made. There are situations where solid lead metal
is a decent
vibration damping material, and others where compacted cotton is better, and
just want a shock absorber or a vibration isolation mounting.
So what kind of vibration do you want to damp? In what environment? Any
constraints on cost,
size, weight or compatibility with other materials? Hmmm?
It's somewhat redundant to say that a material
should be lossy to be a good damping material.
Metals are therefore among the worst, and
rubber is among the best. Rubber is widely
used for engine and transmission mounts in
I've heard of asphalt being used, applied to
sheet metal in a car body. Cork is often
used for making sound-proof walls for
Look at http://septon.info/en/hybrar/what_hybrar.html . Kuraray has some
block copolymers they recommend for vibration damping and I think you'll
find some discussion on their web site about the need for the Tg (that is,
tan delta peak) near the temperature where you want the damping. They have
a neat demo where they take two seeminly identical rubber balls, about the
size of marbles, and drop them on a table from a height of about two feet.
One ball will bounce high as you'd expect, but the other lands with a thud
and doesn't bounce at all.
Polyisobutylene, butyl rubber, has no bounce at all. All the free
space is crammed with sidechains. That also blocks gas diffusion,
hence its use as inner tubes. Add high loss layers with horribly
impedance mis-matched interfaces like dry sand.
One nice demo is a handball that is molded one hemisphere bouncy
rubber or Super Ball and the other butyl rubber, both back. Wanging
the thing on a hard floor shoots it high and it bounces until it hits
the other side. Then, "thud" and nothing.
Oh LORD !!
Lord vibration isolators at www.lord.com
One of the large commercial manufacturers of vibration isolating
components (usually elastomers and viscoelastomers).
Lord and other vibration control companies usually have some tutorial
information on their web sites and in their catalogs to educate
Educating potential users by web or catalog is a lot cheaper than trying
to educate alleged customer by telephone. It is a lot less tiring on
Oh LORD !!!!
1) Eat Till SATISFIED, Not STUFFED... Atkins repeated 9 times in the book
2) Exercise: It's Non-Negotiable..... Chapter 22 title, Atkins book
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