Hi all!
Anybody have a good reference / approach for computing the first critical bending frequency?
I have been using the Jeffcott rotor approach; however I'm not sure which value to use for the shaft-rotor bending stiffness. Including just the shaft (and using the Wikipedia-level beam bending equations to get the maximum deflection per unit force); however estimating the bending stiffness of the laminated core sounds quite fuzzy. Anyone aware of any published rule-of-thumb numbers for e.g. the Young's modulus?