Procedure for torsional-vibration calculations in ice

Abstract

The safety of navigation at sea is closely connected to the reasonable operation of the marine power transmission system of a vessel. The propulsion unit inside a ship is considered as one of the most significant on-board systems that is mostly subjected to dynamic loading. The dynamic behavior can cause various vibrations along the propulsion line that will substantially affect the propulsion shaft’s reliability and efficiency. In general, the most vital factor that can influence the shafting design is the shafting vibration behavior, particularly the torsional vibration behavior. The demand for proper vibration analysis grows rapidly in the last decade due to the growing adverse effects of fatigue failures in the shaft machinery systems, and also to define and identify the main torsional vibration characteristics as they differ from other types of vibrations to an extent. Hence the validity of a proper shafting design can only be checked through a detailed torsional vibration analysis.