Damping materials

skidesmond · Post by **skidesmond** » Fri Feb 25, 2011 5:13 am

(* Disclaimer - As I've said before, I'm not an engineer, so engineers please chime in. A lot of the technical data provided in the links below is gobbilly gook *)

I've been pleased with most of the skis I've built. They all hold extremely well on edge, have nice flex, etc. But a minor short coming I'm noticing is damping with the exception of 1 pair that is all ash and on the heavy side. But aside from that one, I generally get a little more "feedback" in the skis than a commercial ski of the same shape/size.

So now I feel I need to tweak the skis a little more, especially the ones that have a lighter core and build a little more damping into the ski.

I came across this company that builds damping systems:

http://www.roush.com/nvh/products-and-s ... 3wode2quDA

This material is interesting:
http://www.roush.com/nvh/damping-damper ... d-nvh.aspx

http://www.roush.com/Portals/1/Download ... cturer.pdf

I know metal alloys ( titanal and AL) are used in high end skis, especially racing skis to provide strength, rigidity and damping effects. Based on that, do you think any of the above materials would work in a ski/board?

I've also thought of using cork in a layup ( http://www.corecork.amorim.com/client/s ... e.asp?id=1 ) and had a contact there but nothing ever materialized from them. They did tell me they were working with Burton and cork for their boards. I haven't heard back from them in sometime.

Thoughts?

Brazen · Post by **Brazen** » Fri Feb 25, 2011 8:51 am

I've created something that I really can't share here prior to patent. But...I'm following along the lines of an electro-rheologic damping system. I wish I could say more...it's really exciting.

skidesmond · Post by **skidesmond** » Fri Feb 25, 2011 9:24 am

Sounds very interesting. Good luck w/ the patent. Looking forward to hearing more about it.

bigKam · Post by **bigKam** » Thu Mar 17, 2011 8:11 pm

skidesmond's electro-rheologic damping idea is intriguing; for example, MR fluid is great for damping in military vehicles and even motor cycle shocks, but it's not necessarily passive. Having a small cavity near the tip of the ski filled with fine loose particles works well too!

I've been working on damping for skis for some time now. There are some nice ideas out there. Rossi's constrain layer damping works really well, but it's patented. I did some testing in my lab and found it to be really effective. I'm also working on a number of other concepts, but they are all basically the same -- some way shape or form of energy removal. One can get really creative here...

But keep in mind that adding metal to a ski doesn't always provide damping. But if it's used correctly with the right combination of materials, in the right spot, then you might be able to improve damping.

skidesmond · Post by **skidesmond** » Sun Mar 20, 2011 6:21 am

bigKam wrote:skidesmond's electro-rheologic damping idea is intriguing; for example, MR fluid is great for damping in military vehicles and even motor cycle shocks, but it's not necessarily passive. Having a small cavity near the tip of the ski filled with fine loose particles works well too!

I've been working on damping for skis for some time now. There are some nice ideas out there. Rossi's constrain layer damping works really well, but it's patented. I did some testing in my lab and found it to be really effective. I'm also working on a number of other concepts, but they are all basically the same -- some way shape or form of energy removal. One can get really creative here...

But keep in mind that adding metal to a ski doesn't always provide damping. But if it's used correctly with the right combination of materials, in the right spot, then you might be able to improve damping.

I'll be doing more research on the topic over the spring/summer months. I think metal has it's place in some type of skis like racing (since many commercial manufactures use it) but I don't think I'd use it in a typical twin tip/park ski. I think it may delam too easily in a laminated layup, given the sudden impacts.

Getting a fluid like material in a ski in a typical laminated layup seems like a challenge..... fun, fun, fun!

MontuckyMadman · Post by **MontuckyMadman** » Wed Mar 23, 2011 9:26 pm

Hey kam. Would you like to elaborate on the rossi technique or how someone could create a cavity and use fine particles or other details related to the use of metal in a sandwhich laminate?

skidesmond · Post by **skidesmond** » Thu Mar 31, 2011 6:28 am

Here's a test that was done and how they put the fluid into a laminated beam. It at least will get you thinking:
http://www.sites.mech.ubc.ca/~phani/Pub ... P_2003.pdf

Also looking for ideas on how to conduct tests for torsional rigidity and be able to measure it. Would a local university w/ and engineering dept be a place to start?, ideas on how I could do it myself with some degree of accuracy?....

I'm making a number of sample laminations I want to test that will be constructed using different materials. I'd like to be able to test the damping/vibration, rigidity torsionally (twisting motion) and longitudinally (flexing the camber).

The camber longitudinal test I think I have under control. I'm simply using weights to see how much weight it takes to flatten sample piece.

Any ideas/suggestions will be a great help. All results will be posted. Thanks.

skidesmond · Post by **skidesmond** » Thu Mar 31, 2011 4:16 pm

Ha! I really think this forum has all the answers! The thread below has info on testing flex and torsional rigidity.

Here's the start of the thread: http://www.skibuilders.com/phpBB2/viewt ... sc&start=0

My answer was found here on page 7 of the thread.
http://www.skibuilders.com/phpBB2/viewt ... c&start=90

So I think I have enough info to start conducting my tests.

Found another site for making a simple torsion test machine: http://www.doctorsnowboard.co.uk/?page_id=55

Ski Builders Forum

Ski Builders Forum

Damping materials

Damping materials