API RP 11S8 pdf download Recommended Practice on Electric Submersible System Vibrations A characteristic of misalignment and bent shafts is that vibration will occur in both radial and axial directions. Ingeneral, whenever the amplitude of axial vibration is greater than 50 % of the highest radial vibration, thenmisalignment or a bent shaft should be suspected. 4.3.4 Flow lnduced Pump vibration...