Official Answer
Answer
Groove wall deformation in soft materials like Aluminum (e.g., 6061-T6) is caused by the bearing stress exceeding the compressive yield strength of the material. The thrust load $P$ is concentrated on a small area $\pi D d$. Because Aluminum has a much lower yield strength than the steel ring, the 'corner' of the groove will round off, allowing the ring to tilt (dish) and eventually fail. The solution is to: 1) Increase the groove depth $d$; 2) Increase the shaft/bore diameter $D$; 3) Use a 'Hard Anodize' coating to increase surface hardness; or 4) Use a steel 'Thrust Washer' between the retained part and the ring to distribute the load more evenly.
