I'm designing an aluminium shaft hub for a 16mm keyed shaft with a maximum torque of 30Nm. However, stress analysis tells me that the keyway can suffer too much stress:
If my understanding is correct, keyways have little or no fillet, then how is stress relieved? In general, is driving an aluminium hub with a keyed shaft for ~30Nm a bad idea? There are some aluminium hubs with keyway on the market, but it's not clear if they're designed for 30Nm. Could I be missing something in my design?
UPDATE: I've added 0.5 fillets in the keyway, but the stresses are still very high: