Answer
In wave spring design, the number of waves $N$ per turn is a primary driver of both load and stress. The stress $\sigma$ is calculated as $\sigma = (3 \cdot \pi \cdot P \cdot D_m) / (4 \cdot b \cdot t^2 \cdot N^2)$. This equation demonstrates an inverse square relationship between the number of waves and the stress. By increasing $N$ for a fixed load $P$, the stress level decreases exponentially. However, an increase in $N$ also increases the spring rate $k$. Designers in automotive transmission systems often optimize $N$ to balance the required axial force against the fatigue limit of the material, typically aiming for stress levels below 80 percent of the minimum tensile strength of 17-7PH CH900 to ensure longevity during high-cycle operation.
