Shaft Sizing

max11

Hiya

I was hoping that somebody would be able to help me.

I need to size a shaft coming from a turbocharger spinning at 150,000rpm the shaft needs to transmit 9Nm and 200mm in length, the shear stress of the material is 457MPa.

I need to size the diameter of the shaft and know that it is going to be very small but cant seem to find a formula that gives me a sensible answer, right now I am using a formula from engineering toolbox (http://www.engineeringtoolbox.com/to...fts-d_947.html)

D = 1.72 (Tmax/σmax)1/3

But this give me a diameter of 0.46mm which seems so small that it would just twist and break.

an y help greatly appreciated.

Cheers

Q_Goest

Hi Max. Check your work again. I'm getting 4.65 mm.