Answer
For a Crest-to-Crest wave spring, the load $P$ for a given deflection $f$ is derived from the modified Moyer's formula: $P = \frac{E b t^3 n f}{K D_m^3} \cdot \frac{I_D}{O_D}$, where $E$ is the Modulus of Elasticity, $b$ is the radial wall, $t$ is the material thickness, $n$ is the number of active waves per turn, and $D_m$ is the mean diameter. The correction factor $K$ accounts for the curvature of the waves and the transition between crests. In a shim-end configuration, the load-deflection curve becomes more linear compared to plain ends because the shim provides a uniform 360-degree contact surface, reducing the localized stress concentrations and preventing 'wave-nesting' during the initial compression phase. If $K$ is not accurately modeled based on the $D_m/b$ ratio, the calculated rate can deviate by up to 15 percent as the spring approaches its solid height.
