Official Answer
Answer
Ring dishing is the axial deflection of the ring's radial wall under load, transforming it from a flat washer shape to a conical shape. The amount of dishing is a function of the axial force $P$ and the material's stiffness. If the dishing angle exceeds approximately $7^{\circ}$, the ring is at high risk of jumping the groove. The safety factor $S_f$ for thrust capacity is usually $2.0$ to $3.0$. If a failure occurs and the ring appears 'coned' but not sheared, it indicates that the load exceeded the dishing limit. This is often caused by an unexpected impact load. The solution is to increase the material thickness $T$ or the radial wall $b$ to increase the 'coning' stiffness, defined by $M = σ \cdot Z$ where $Z$ is the section modulus.
