Answer
As a wave spring is compressed from its free height to a working height, the waves flatten, causing the overall diameter of the spring to expand. The expansion $\Delta D$ can be approximated as $\Delta D = \sqrt{D^2 + (H^2 - h^2) \cdot \frac{n^2-1}{\pi^2}} - D$, where $H$ is the free height and $h$ is the compressed height. If the spring is installed in a housing with insufficient radial clearance, the spring will bind against the housing wall. This binding creates frictional resistance, leading to a non-linear increase in load and potential 'load spikes.' Furthermore, the restricted expansion causes localized stress concentrations at the crests, which significantly reduces the fatigue life of the component due to the superposition of radial constraint stress and axial bending stress.
