What are the considerations for calculating the 'Centrifugal Capacity' of an internal spiral retaining ring in a high-speed bore?

Unlike external rings, internal rings are 'pushed' into the groove by centrifugal force, which actually increases their security. However, at extreme speeds, the centrifugal force can cause the ring to expand so much that the hoop stress $ ext{σ}_h = _x000d_ho imes v^2$ exceeds the material's yield strength. If the ring plastically expands, it will lose its 'set' and may not contract back into the groove when the rotation stops, leading to failure during the next startup. The design limit is typically set so that the centrifugal stress remains below $70\%$ of the material's yield strength $S_y$.