# Helical spring with square cross section

Determine mechanical properties of a helical spring with wire thickness 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.

$$G=\dfrac {E}{2(1+ν)}$$

$$k=\dfrac {\ Gd^{4}}{44.9n_{w}r^{3}}$$

$$v_{(F)}=\dfrac {\ 44.9Fn_{w}r^{3}} {Gd^{4}}$$

$$v_{max}=\dfrac {\ 44.9n_{w}r^{2}σ} {4.8Gd}$$

$$σ_{(F)}=\dfrac {\ 4.8Fr} {d^{3}}$$