Official Answer
Answer
Static thrust loads are limited by the shear strength of the ring and the yield of the groove. Impact loads, however, involve kinetic energy $U = \frac{1}{2} m v^2$ that must be absorbed. The impact capacity is roughly half of the static capacity because the ring and groove must deform elastically to absorb the energy. High-velocity impacts can cause the ring to 'jump' out of the groove due to the momentary radial expansion caused by the axial pulse. Designers use a safety factor $K=6$ for impact, and often specify a 'Heavy Duty' series ring with a larger cross-section to increase the mass and stiffness.
