damping coefficient for common steel alloys

[rdaniel2]

My kids and grandkids are involved in go karts. The go kart has to lift the inside rear wheel to turn as the rear axle is solid. Tuning or adjusting the kart to optimize the performance often involves changing the rear axle to a harder or softer axle. Since the o.d. of the axle is fixed by the bearing size I thought that the change in handling characteristics had to be based on the moment of the axle, i.e. wall thickness since all steels have an almost identical modulus. How wrong I was. I have seen axles with identical o.d. and i.d. exhibit markedly different handling characteristics. I now feel that maybe the damping coefficient of the axle is the difference.
Does anyone know of info relating the damping characteristics of the common steel alloys? I can cut coupons from the axles and have them analyzed but would prefer deferring that expense until I can see some comparison #s on the common steels.

 

[hacksaw]

contact a shop that builds axles or drive shafts

materials selection and heat treatment given not damping.

 

[rdaniel2]

For a go kart to turn it must lift the inside rear wheel off the pavement. Axles are limited to steel by the rules.
I don't think the properties I want to investigate can be handled by a shop that makes automotive axles or driveshafts.

 

[GregLocock]

Realistically I doubt that the damping of a system that includes a slipping tyre is going to be much affected by the internal damping of the steel axle. I don't have good information to hand, the following ggogle search seems promising

http://www.google.com.au/search?q=damping+of+different+steel+grades

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[GBor]

In shipbuilding (very large ships), analyst generally add 2% damping for Rayleigh. These ships are generally built of mild steel (A36). Not sure if this is what you are looking for, but...

Garland E. Borowski, PE

 

[GregLocock]

Internal damping coefficient for steel is around 0.1%, it's (say) 1% once joints are made.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[vanstoja]

For a discussion of metals damping properties see vanstoja and other replies in Thread384-49887 and Thread384-110306.