“#Springs are characterized by relatively low energy density (about 0.1 Wh/kg for steel) ...[but] high power density (around 10 kW/kg for steel)”. I guess that would be 360 J/kg.
on 02016-05-24“(to good approximation) elastic polymers do not store any potential energy in stretched chemical bonds or elastic work done in stretching molecules, ... Instead, the energy to do work comes entirely from thermal energy, and (as in the case of an expanding ideal gas) only the positive entropy change of the polymer allows its internal thermal energy to be converted efficiently (100% in theory) into work.” #elasticity #springs
on 02016-05-24#energy-density of #springs: 2.3 Wh/kg (8.3 kJ/kg) for AISI A11 tool steel, 1.1 Wh/kg for rubber (4.0 kJ/kg), 6.0 Wh/kg for carbon fiber (21.6 kJ/kg). By David MacKay, who died shortly afterwards.
on 02015-11-192004 #pdf #paper about #antisprings for seismic isolation. Clarifies that YES, an antispring has a negative #stiffness coefficient. In this case they’re combining antisprings with regular springs to cancel out their stiffness and get near-zero restoring force for small displacements. They managed to get a resonant frequency of 0.3 Hz with #maraging steel #springs (to reduce creep), which doesn’t sound that great to me, but whatever.
on 02015-11-09A patent application for a kind of tubular #springs. #patents
on 02015-08-18More equations and diagrams about #springs in #mecheng
on 02015-08-13Equations and diagrams about #springs #mecheng
on 02015-08-13