DRIVE SHAFT FAILURE ANALYSIS ON A MULTISTAGE VERTICAL TURBINDRIVE TURBINE PUMP IN RIVER WATER SUPPLY SERVICE IN A NICKEL AND COBALT MINE IN MADAGASCAR - BASED ON ODS AND FEA – (PPT)

摘要

1, The failure mechanism of the drive shaft was caused by the elevated axial and torsional oscillation loads in combination with the jammed driveshaft spline. 2, The situation became severe because an axial (horizontal parallel to the crankshaft) pump natural frequency and torsional shaft assembly natural frequency were simultaneously in resonance with an unexpectedly high 1.5x running speed harmonic, which appeared due to a poorly tuned engine (resulting in a 1/2x rpm fundamental and its harmonics). 3, The 2nd torsional natural frequency of the drive shaft was determined to be at 42.0 Hz (Pump C). The separation margin from 1.5x running speed is within 5% from both the pump and engine speed. 4, The torsional oscillation was observed to be as high as 94% zero-to-peak of the mean torque value.