Calculator for round wire helical springs
Diameter of spring wire d	10-3 m
Mean coil diameter D	10-3 m
Number of active coils n	-
Shear modulus G = E / ( 2 ( 1+v ) )	109 Pa
Spring force F	N
Spring outer diameter Dout = D + d	10-3 m
Spring radius r = D / 2	10-3 m
Spring length closed (solid) Lc = n d	10-3 m
Spring deflection f	10-3 m
Energy stored W = F f / 2	J
Spring stiffness k = dF / df = F / f	103 N/m
Spring length free L0 > Lc + f	10-3 m
Pitch of lead s = L0 / n	10-3 m
Shear stress τ	106 Pa
www.tribology-abc.com