Analyze a failure where a spiral retaining ring is 'dished' after being subjected to a heavy thrust load.

'Dishing' is a deformation where the ring's cross-section twists under load, caused by the moment created by the contact point of the retained part. This occurs when the thrust load $P$ exceeds the groove material's yield strength or the ring's ability to resist twisting. The moment is $M = P \times (clearance)$. If the groove wall deforms, the ring loses its perpendicularity. The allowable thrust load based on groove deformation is $P_g = \frac{D d S_y \pi}{K}$ where $d$ is the groove depth and $S_y$ is the yield strength of the housing. If the housing is soft (e.g., Aluminum), a deeper groove or a ring with a larger radial wall is required to distribute the load.