On String Breakage

[Roger Jolly]

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>
>  
> As for the force discussion, Newton's second law has the resultant equation
> the F=ma. Which is force equals the mass times the acceleration.
Disregarding
> friction, the forces input into a linkage system will equal the forces
> produced by a linkage system. This means F[at the key] = F[at the hammer] =
> F[at the string]. Going further, if we subsitute the mass x the acceleration
> (ma)side of the equation, then ma[force at key] = ma [impact of hammer] =
> ma[string vibration].




Hi Tom,
           There is a lot more energy loss, other than friction. Bending of
the
various components, key, jack, hammershank etc. The hammer absorbs a greater
amount as the shoulders flex. ( combined with friction, action saturation)
Hard hammers tend to produce a very strong fundamental, (mid section upwards)
with small partial development, therefore it will produce a wider string
excussion on a repeated blow. This will increase fatigue, and hence breakage.
The point is that, a very significant proportion of the energy is dissipated
within the action and hammer.
To find the actual energy that the string is producing, you need to know the
sum of the RMS value of all the partials.
The louder that you play the instrument, the less efficient it becomes as you
approach saturation.
Regards Roger
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505 
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