Helical spring with round cross section


Determine mechanical properties of a helical spring with wire diameter d, radius r, shear modulus G and nw as number of active windings. Calculate also deflection v and tension σ as a function of force F.

The shear modulus can be calculated using Young's Modulus and Poisson's ratio of a material.

\( G=\dfrac {E}{2(1+ν)}\)

F d D m r n w = 6

\(k=\dfrac {\ Gd^{3}}{64n_{w}r^{3}}\)

\( v_{(F)}=\dfrac {\ 64Fn_{w}r^{3}} {Gd^{4}} \)

\( v_{max}=\dfrac {\ 4n_{w}r^{2}πσ} {Gd} \)

\(σ_{(F)}=\dfrac {\ 16Fr} {πd^{3}} \)