The Tuned-Mass Damper

[Bob Sciamanda <sciamanda@worldnet.att.net>]

(This is a repeat posting; the first one died somewhere?!?)

Bob Sciamanda wrote:
> brian whatcott wrote:
> > . . .
> > I was hoping for an illuminating answer to this interesting physical
> >  question of considerable practical importance.
> > . . .
>
> OK, I'll give it a shot.  If one hangs a mass from a spring and then
> drives the UPPER end of the spring into oscillation with a sinusoidal
> driving force (this is Leigh's example system in an MET post, but with a
> sinusoidal driver), this same force is transmitted to the mass  by the
> (massless, frictionless) spring.  Now the mass' acceleration will also
> be in phase with this force and the mass' displacement is always 180
> degrees away from its acceleration, resonance or no!
>
> Hope this is useful,
> -Bob
> --
On third thought, the described system is specified to be damped, so
that the above does not apply.  I can only guess that it is tuned to be
very far OFF RESONANCE, ie., driven at a high enough frequency that the
mass term dominates and the above phase relationships hold
approximately. I am not familiar with these systems; I'm only guessing -
any seismologists or architects out there?

-Bob
-- 


Bob Sciamanda                           sciamanda@edinboro.edu
Dept of Physics                         sciamanda@worldnet.att.net
Edinboro Univ of PA                    
http://www.edinboro.edu/~sciamanda/home.html
Edinboro, PA                            (814)838-7185


-- 


Bob Sciamanda				sciamanda@edinboro.edu
Dept of Physics				sciamanda@worldnet.att.net
Edinboro Univ of PA			http://www.edinboro.edu/~sciamanda/home.html
Edinboro, PA				(814)838-7185

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