Answer
For a Crest-to-Crest wave spring, the spring rate $K$ is determined by the material properties and geometric configuration. The formula is $K = \frac{E b t^3 N^4}{K_w D_m^3 n}$, where $E$ is the Young's Modulus, $b$ is the radial wall, $t$ is the material thickness, $N$ is the number of waves per turn, $n$ is the number of active turns, and $D_m$ is the mean diameter. The factor $K_w$ accounts for the curvature effect. To calculate the operating stress $\sigma$, we use $\sigma = \frac{3 π P D_m}{4 b t^2 N^2}$, where $P$ is the applied load. It is critical to ensure that $\sigma$ does not exceed the minimum yield strength of the material, typically $17-7PH$ CH900, after accounting for the safety factor. In high-precision aerospace applications, $D_m$ must be calculated at the work height due to radial expansion.
