How to Combine Stress Concentrations for Multiple Keyways on a Shaft?

[robs314]

Hello

I have done a Soderberg shaft design calculation, taking into account the stress concentration for a keyway. However, I've just noticed that I might need to adapt this for a feather type keyseat, or 2 (parallel, 180deg apart) keyways in the same cross section.

I'm sure I read somewhere about how to combine the stress concentrations in this situation, but I can't find where I read it. Does anyone know off the top of their heads?

Cheers

 

[edgepflow]

Try Machinery's Handbook. I don't have it in front of me, but it has a lot of information on stress concentrations.