Answer
The spring rate $k$ for a Crest-to-Crest wave spring is defined by the relationship between the applied load $P$ and the deflection $f$. Using the specialized Munter's formula, the load is expressed as $P = (E \cdot b \cdot t^3 \cdot f \cdot N) / (D_m^3 \cdot n^4 \cdot K)$, where $E$ is the Modulus of Elasticity, $b$ is the radial wall, $t$ is the material thickness, $N$ is the number of waves per turn, $n$ is the number of turns, and $D_m$ is the mean diameter. To find the spring rate $k = P/f$, we rearrange to $k = (E \cdot b \cdot t^3 \cdot N) / (D_m^3 \cdot n^4 \cdot K)$. The factor $K$ is a correction constant for the wave profile, typically around 1.0 for theoretical sinusoidal waves but adjusted for actual crest contact geometry. For high-precision aerospace applications, it is critical to realize that the number of turns $n$ is in the denominator with a power of 4, meaning increasing the number of turns significantly reduces the spring rate, allowing for high deflection in restricted spaces.
