[Kevin Sevcik]

Adam,

I ran more or less the same analysis just now. The true deformation isn't near as bad as your picture, you're looking at the scaled deformation. At any rate, the stresses are marginal at the stall torque of the CIM, but keys don't apply load on the keyway exactly like that in practice, and the worst stresses are at the corners of the keyway, and might be relieved by localized yielding in that area. Plus, the CIM is very rarely going to be stalled during actual use. So, again, I think the best test would be a mock-up to test the design in practice.