Answer
Dynamic buckling occurs when a wave spring is compressed rapidly and the lateral forces overcome the spring's structural stiffness, causing it to bow sideways. This is most common in springs with a high 'slenderness ratio' (Free Height / Mean Diameter > 1.5). Indicators include wear marks on the ID or OD of the spring where it has rubbed against the shaft or bore, and an inconsistent load-deflection profile. To correct buckling, designers can use a pilot (shaft or bore), or redesign the spring with a wider radial wall ($b$) to increase lateral stiffness. In Crest-to-Crest designs, adding more waves ($N$) per turn can also help stabilize the spring by providing more contact points, effectively reducing the 'unsupported' length of each wave segment.
