Composite Coil Springs
Composite Coil Springs
(OP)
I am looking for coil springs made of fiber reinforced plastic. Does anybody know, where I could get such springs?
Thanks a lot for every hint,
ulrich
Thanks a lot for every hint,
ulrich





RE: Composite Coil Springs
http://israelkk.googlepages.com/home
RE: Composite Coil Springs
http://www.sardou.net/accueil4.htm
RE: Composite Coil Springs
http://www.heli-cal.com/
RE: Composite Coil Springs
Before jumping to the state of the art and most expensive spring manufacturing process, a normal standard wire coiled spring has to be checked. Anyway, ulrichAT is looking for springs made of composite materials and I assume he has good reasons for it.
RE: Composite Coil Springs
TVP, thanks for your link, this is quite what I'm looking for. But this company is located in France. Do you know something similar in the US?
RE: Composite Coil Springs
I do not know of any company other than Sardou that makes helical springs from fiber-reinforced polymer matrix composites. I know Hexcel was working on composite leaf springs, so you may try them. Have you discussed your application with TIMET? They have worked on some solutions that can lower the cost of titanium, including the new alloy TIMET LCB.
RE: Composite Coil Springs
Can you provide the weight, size, force, deflection etc. that are required from the springs.
May be an optimize metal spring can do the job or get close?
RE: Composite Coil Springs
@TVP: Thanks for the hints, I will check that.
Both of you thanks again for your help,
ulrichAT
RE: Composite Coil Springs
Did you try a preset (scaragged) spring? It can take up to 70% more stress then non-preset spring.
RE: Composite Coil Springs
If you can give me a steel spring which meets these requirements you will make me very happy!
Regards,
ulrichAT
RE: Composite Coil Springs
Also, what friction (or damping) is acceptable.
I suspect that nothing short of a diamond will meet that spec, due to the weight requirement. That in itself looks rather arbitrary, since it is almost exactly one pound in the old money.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Composite Coil Springs
But you are right, we also believe that you cannot meet this specification with a steel spring. What we try to find out is, whether it is possible with a fiber reinforced material or not.
What do you think? Is it possible to reach this goal with FRP? If yes, do you know a company which could build this spring?
Best regards,
ulrichAT
RE: Composite Coil Springs
http://israelkk.googlepages.com/home
RE: Composite Coil Springs
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Composite Coil Springs
What "metal wire" type did you use for your analysis?
RE: Composite Coil Springs
Aside from the aformention Helical Springs here are two other manufacturers of machined springs.
http://ww
http://www.taylordevices.com/MachinedSprings.htm
This information is from my buddy who works with weird science and engineering secret stuff.
RE: Composite Coil Springs
ulrichAT
RE: Composite Coil Springs
ulrichAT
RE: Composite Coil Springs
RE: Composite Coil Springs
RE: Composite Coil Springs
RE: Composite Coil Springs
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RE: Composite Coil Springs
Best regards,
Matthew Ian Loew
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Composite Coil Springs
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Composite Coil Springs
U/V=k(max working stress)^2/G for a torsional system.
where
U= energy stored
V= volume of spring material
k=facor depending on spring configuration
To convert this to weight efficiency we get
U/W=U/Vd
d= density
It turns out that a helical spring with a k value of 1/5.4 (I assumed a spring index of 4) is the most efficient for weight efficiency. I calculated values for alloy steel and berrylium copper to test this formula with the following results:
Steel : 1/5.4(70000)^2/(11.5*10^6*.287)=275 in lb/lb
Berrylium copper: 1/5.4(50000)^2/(6.5*10^6*.297)= 239 in lb/lb
According to these figures (I guessed at the fatigue stresses), for steel you would need
1000*2.5/2/275 = 4.5 lbs steel (U=1000lb*2.5"/2)
and even more for Berrylium bronze. So as everybody has said these metals aren't even close to the requirement of 1 pound.
The key to getting a material is to maximize the
allowable stress^2/density. I don't think that titanium will do it but it is off the table anyway because of the cost.
* Rothbart, Mechanical Design and Systems Handbook, McGraw Hill, 1st and 2nd editions
RE: Composite Coil Springs
That's why I questioned the fixed mass requirement of the spring, the only time the mass of a component is fixed is when mass is the raison d'etre of the component. In ANY other system there is a compromise - for instance, if the spring were 10% heavier, could something else be lightened to compensate? There must be a tradeoff.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.