TourTourCalculator 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
 
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