MK belldeal-actuallly switchin" to Natural Frequency

[Gray E Fowler]

"Agree w/ John about using foam as a vibration damper. Also, someone much 
wiser than me pointed out that whatever is installed should NOT be 
halfway, 1/4 way, or any reasonable fraction of the pushrod length because 
these may end up as stationary nodes in the vibrating rod, and end up 
doing no good. 
Rick"

Rick
Could happen but consider this.....The resonance or flutter results from a 
combination of factors. One is the modulus of the item and one is the 
mass. In the case of our push rod scenario, the cf rod has a consistent 
stiffness the length of the rod, so that is constant, but the longer the 
rod the easier it is to buckle. A full length rod has a certain mass and a 
half length rod (foam in the middle) has half that mass. The apparent 
stiffness of the half rod is greater and the mass is less therefore what 
make a full length rod resonate most likely will not make the half rod do 
the same. In addition, having the rod in contact with the foam dampens the 
resonance, as opposed to a situation where the rod is hard fastened, and 
therfore sets up a new set of resonance factor based on the mass and 
modulus again.
Hopefully this makes sense...I absorbed this primitive knowledge hanging 
around true stress weenies... 



Gray Fowler
Principal Chemical Engineer
Composites Engineering
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