Official Answer
Answer
Axial impact loading occurs when the retained component slams against the ring, common in pneumatic hammers or rapid-shift transmissions. Diagnostic signs include 'dishing' of the ring turns and shear-lip formation on the groove's edge. Unlike static over-stressing, impact failure often shows 'brinelling' of the groove wall where the ring has been hammered into the material. If the impact energy $E = \frac{1}{2} m v^2$ exceeds the plastic deformation work of the groove/ring system, the ring will eventually spiral out of the groove or fracture at the grain boundaries. Solution strategies include using a heavier cross-section ring or a 'series-50' style groove which provides more wall contact area.
