Soundboard stiffening

[David Skolnik]

David-
My instinct was in accord with yours, but then I looked at some of my 
Neuses gram resistance gauges, and, what do you know? The graduations are 
all equally spaced!!  So SOME springs, at least, work as Phil describes.  I 
don't know if different materials or configurations might have different, 
perhaps even non-linear, characteristics. Chances are, both the spring and 
the arch are inadequate models to represent the dynamics of a soundboard.

David Skolnik


At 06:22 AM 2/2/2004 -0800, you wrote:
>Well, you're the engineer, but if it takes 100lbs to compress the
>soundboard 1", doesn't it take considerably more than that to compress it
>the next inch?  Doesn't that suggest a stiffening of the board as it's
>compressed?
>
>David Love
>davidlovepianos@earthlink.net
>
>
> > [Original Message]
> > From: Phillip Ford <fordpiano@earthlink.net>
> > To: Pianotech <pianotech@ptg.org>
> > Date: 2/1/2004 11:15:28 PM
> > Subject: RE: Soundboard stiffening
> >
> > >At the risk of oversimplification, isn't a crowned soundboard just a big
> > >spring, the more you compress it, the more rigid it becomes?
> > >
> > >David Love
> > >davidlovepianos@earthlink.net
> > >
> >
> > David,
> >
> > This is the point that I was trying to make.  I believe that the
> > soundboard is essentially just a big spring.  A spring doesn't get
> > more rigid or stiff the more you compress it.  Within its working
> > range it has a constant spring rate or stiffness.  If a spring's
> > spring rate is 100 lb/in. then it takes 100 lbs to deflect it the
> > first inch.  It takes 100 additional lbs to deflect it another inch.
> > It doesn't matter if you start from a zero deflection point or an
> > initial 1 inch deflection point - the spring rate (or stiffness) is
> > still 100 lbs/in.  It's not getting stiffer because you're putting
> > load on it or deflecting it.  True, it takes twice as much load to
> > get twice as much deflection, but that is still a constant stiffness.
> > I would expect a soundboard to work the same way.  If the board is
> > actually getting stiffer as a result of applied load then it's not
> > acting like a spring or a beam, and I would like to understand what
> > mechanism is causing that to happen.
> >
> > Phil Ford
> > _______________________________________________
> > pianotech list info: https://www.moypiano.com/resources/#archives
>
>
>
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