Energy storage density of coiled springs

stanleykorn

I’m looking for an information source on the energy storage density of coiled springs made of various materials. Of particular interest are steel, titanium, carbon fiber, and carbon nanotubes.

Mech_Engineer

The stored energy in a spring is 1/2*K*x^2, so from an energy storage standpoint it would be best to have a spring that had a large deflection (high yield strength). This brings Titanium into the picture due to its very large yield point. It's possible carbon fiber would be pretty good from a weight ratio standpoint because it's so light, but it is also very stiff which means it wouldn't deflect very far before breaking (keep in mind the x^2 in the energy formula).

You'll basically have to do some calculation of a theoretical spring of certain dimensions made out of a specific material. You might consider analyzing a simpler spring like a leaf spring since a load will be taken in pue tension/compression in the beam, where as a coil spring tends to have a combination of bending and torsional sresses. It probably isn't useful to discuss a carbon nanotube spring, since they don't exist (and carbo nanotubes are best in tension, like carbon fiber).

dr dodge

Quartz can be made into some very good springs. the advantage over metals, no memory (or hysteresis) even over years of space travel.

dr