Can a standard practice with large structures work for us?

Introducing the Tuned Mass Damper (TMD).

 

There are ways to reduce wobbling and add stability to your board. Four ways that I've heard about:

      1. Split truck angles - reduce the rear hanger angle to add stability.
      2. Change to harder bushings.
      3. Use 3-link trucks like in Stooge Raceboards.
      4. Add a genuine damper to the front truck.

*none of the links above is a promotion

 

Personally I've used only the first two, but the damper looks cool!

These work.
But today let's explore something entirely different, something you've never seen on a board (and maybe soon you will).

 

A different approach

What if we can avoid stiffening the trucks and still reduce the unwanted vibrations?

Introducing Tuned Mass Damper (TMD). The basic  premise is shown in the video:

The idea is to add an additional mass+spring to the system. The added mass+spring are tuned as to have natural frequency as close as possible to the main frequency of the system. This is practiced routinely in skyscrapers.

 

This causes the added mass to wobble. The added mass is smaller, so it vibrates more.
By doing so it reduces the vibration levels of the main system.

 

A quick hack

In our case, adding mass to your board can reduce the vibrations of the board.

Something like this:

added mass on a spring
added mass on a spring

This is literally a piece of aluminum on a spring.

I don’t even know the weight of the block.

 

Later I tried to stiffen it a bit:

 

I like this approach: first make it work and then make it better.

Since I had the Pyramid mount, the attachment was super easy, as are the comparison rides:

putting on/getting off
putting on/getting off

What's next?

For now it’s just a proof of concept.

Only a Mass Damper instead of a tuned one, but so far I'm liking it.

Trying to hit as many road bumps as I can, and to feel the difference.

 

I'm going to follow up with this and see if I can make it reasonably compact and mountable. Some science and numbers won't hurt either.

 

Do you want to see the evolution of this?
Interested in the natural frequencies of your board and the tuning?
Would you like to see the finished product?

Leave a comment and let me know what you think.

Enjoy,
Dani

 

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2 Replies to “Skyscrapers, Longboards and Tuned Mass Dampers”

  1. Hi Dani!

    I like this concept. Out of the box!
    To clarify, is it aimed at speed wobble, or other terrain related wobble?

    What yo do think of attaching the pendulum dampener to the hanger instead of the deck?

    Curious to see your findings.

    1. Glad you like the idea!
      I think it’s more for terrain related vibrations. Then again I don’t know yet.
      The rider feels the deck, so this is what needs to be dampened.
      Happy to have you on board!

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