Official Answer
Answer
The number of waves $Z$ significantly dictates the stiffness and the stress distribution. As $Z$ increases, the spring rate increases by a factor of $Z^4$. However, in aerospace applications where space is constrained, increasing $Z$ reduces the arc length of each wave, leading to higher localized bending stresses $\sigma = \frac{3 \pi P D_m}{2 Z^2 b t^2}$. If $Z$ is too low (e.g., $Z < 3$), the spring may become unstable and tip within the bore. To maintain linearity, the deflection $f$ should not exceed $80\%$ of the available travel to avoid the 'bottoming out' effect where the wave peaks flatten against the contact surfaces, causing an exponential increase in the apparent spring rate.
