"Springiness" of Spring Alloy

[antakamatics]

I am seeking a spring alloy in sheet form with minimal damping. It musth sustain vibration for a long period of time once initially struck or plucked.

I cannot find the proper specificiation, but perhaps loss coefficient, or loss tangent, of coefficient of restitution is close. Nevertheless I have not found a supplier who lists any of these spec's. The other property of importance is corrosion resistance.

Thanks in advance for your advice.

 

[gfbotha]

I don't have all the answers, but think you might consider beryllium copper or stainless steel 302 or 17-7 PH. My gut feel is the stainless steels would have the lower internal damping; less than 1% (it also have a lower density).

You will of course see that losses due to the gas or fluid medium are minimized.

[Not wanted here, but metals like aluminium & magnesium have high damping.]

 

[CoryPad]

Intrinsic damping is the phenomenon and loss coefficient is the material property.

The book Materials Selection in Mechanical Design by Ashby has a chart showing loss coefficient for different materials. It is shown to vary widely for each class of alloy (Mg alloys, Al alloys, Steels, etc.). In terms of absolute smallest loss coefficient, that would be high carbon steels and copper alloys. Choosing a specific one? I can't help much there, although I bet spring temper 301 stainless steel strip would be a good choice.

Regards,

Cory

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

 

[NickE]

Wow, I havn't pulled ashby out in a while.
The damping of the copper alloys vs the ss alloys looks about the same, at that level I think modulus and strength are going to be your new criteria.


Nick
I love materials science!

 

[arunmrao]

BeCu is the preferred alloy.

 

[antakamatics]

Thanks everyone for your help. I myself havent cracked open Ashby's in a long time... and will give this a try. Much obliged.