Posted by Laurence on August 18, 2001 at 10:27:20:
In Reply to: Re: Re: Vibration, damping, and weight posted by Rick Denney on August 17, 2001 at 14:58:39:
Dear Rick,
Thanks for the great postings! I have a question.
You wrote:
Can residual internal stresses affect resonance by preloading parts of the structure? If a horn is assembled under stress (or even if parts are worked and not annealed), some parts of the structure will be left fighting other parts. But even with residual stresses, the added load caused by vibration will create the same deflection as when the brass is unstressed, because the stiffness is constant up to the bending strength of the brass. (This is known as Hooke's Law.) If the residual stress is high enough, however, the horn may dent or fall apart easier because it takes less external stress to reach the strength.
This may be a "brass player's urban myth" but-
I have heard of a brass technician who disassembles and re-assembles factory new instruments (bach trumpets, if memory serves ) in order to relieve stresses at the joining areas. These horns are supposed to resonate more freely.
Should I draw from your assertions that the reduction of these stresses would have no ( or little) effect on the resonse/projection of a horn?
Thanks!