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Tensioned fixed-free vibrations

Tensioned fixed-free vibrations

Tensioned fixed-free vibrations

(OP)
So I figured you might have some insight. I couldn't find anything in any of the ME textbooks I have. But I don't have any specific vibration books.
Motorcycle handlebars vibrate enough to suck.
Steel tubing 18" long ish supported in the middle.
Swap out for solid aluminum -better, but not great.

Obvious solution1. buy the off the shelf motorcycle handlebar tuned mass damper end pieces for $90ish.
Obivious solution2: beryllium tubing. Extremely high stiffness to weight move natural frequency up. Beryllium would be awesome but there's no off the shelf tubing available for sale and the be manufacturer won't talk to you unless you are interested in an order of around $10k min. A**holes.
Obvious solution 3. carbon fiber
Carbon fiber would look ugly on this particular bike. ID says no!
Obvious solution 4. Solid steel. This would definitely increase the stiffness and may be a solution, but it seems like we can do better.
Obvious solution 5. External Custom Tuned mass damper. Throttle and clutch handles prevent external mass so would have to be done internally, pretty much copying existing ots solutions.


Funky idea: tension the handlebars like a guitar string or put them in compression like the neck of the guitar.

So weld in threaded/clearance end caps, and run a steel cable inside with threaded lugs. This should put the bars in compression. Wouldn't this change the natural frequency significantly?

Option B:
Cap the ends, run a steel rod or tube inside, tighten a special nut to put the bars in tension.

It will take a Saturday to play w all this. Any thoughts on which to try first?

J

RE: Tensioned fixed-free vibrations

Do you have an FEA program to compute the mode shapes of the motorcycle handlebars? If so, you could experiment with many of those solutions by running a modal analysis for each configuration and compare the natural frequencies.

Tunalover

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