Joel Morrissette

 

stiffness.. (natural freq = square root of stiffness over mass, so to

get higher frequency either decrease mass or increase stiffness or do

both)

Actually, you needn't increase the mass along the entire fender, just

farthest from the attachment point. I'd have to find my mechanics text, but

you basically want to increase its moment of inertia about the attachment

point (the pivot). One way to do this is stiffen it, another to increase

mass. Another is to move the CG as far from the pivot as you can. Putting

a large mass at the end increases its moment of inertia and therefore lowers

the frequency. Think of the difference between, say, the antenna on your

car with and without one of those antenna toppers. Pluck it without one,

and it will resonate at a higher frequency than with. Move the mass down

the antenna, and the natural frequency should increase.



So the short answer might be to zip-tie a couple cut washers to the end of

the fender, thereby increasing its moment of intertia about the attach

point.



I think that's right...I've been doing o-chem homework for 4 hours, so this

is a MAJOR context switch.



-Joel