Shaft Vibration: Axial Vibration

Abstract

Abstract Torsional vibrations are dominant in shaft lines of diesel marine installations. Axial shaft vibrations are very rarely the cause of severe damage cases, but they generate dynamic forces acting on the ship hull. Four‐stroke marine installations are not of interest due to short stroke, but for two‐stroke diesel engine installations, axial vibration calculations with active and inactive axial dampers are required by some classification societies. This article explains the meaning of the torsional–axial coupling coefficients of the crankshaft for the axial vibrations. Calculated and measured axial amplitudes for an installation with active and inactive axial dampers are compared. The influence of the firing order on axial amplitudes is demonstrated.