Spring Compression Rate

Written by Jerry Ratzlaff on . Posted in Fastener

The constant rate of force expelled by a compression spring per inch or millimeter of travel once a load or force is applied to push and compress the compression spring.

Spring Compression Rate formula

\(\large{ k_s = \frac {G \; d^4} {8 \; D^{3N}} }\)

Where:

\(\large{ k_s }\) = spring constant

\(\large{ G }\) = shear modulus of material

\(\large{ d }\) = wire size (inches)

\(\large{ D }\) = mean diameter (inches)

\(\large{ N }\) = number of active coils

\(\large{ D/N }\) = index correction

  •  \(\large{ G }\) value for common spring materials
    • Copper = 6.5 x 10^6
    • Beryllium Copper = 6.9 x 10^6
    • Inconel = 11.5 x 10^6
    • Monel = 9.6 x 10^6
    • Music Wire = 11.5 x 10^6
    • Phospher Bronze = 5.9 x 10^6
    • Stainless Steel = 11.2 x 10^6
     

Tags: Equations for Spring