Application of the Optimization Methods to the Search of Marine Propulsion Shafting Global Equilibrium in Running Condition

Abstract

Full-film hydrodynamic lubrication of marine propulsion shafting journal bearings in running condition is discussed. Considerable computational difficulties in non-linear determining the quasi-static equilibrium of the shafting are highlighted. To overcome this problem the approach using two optimization methods (the particle swarm method and the interior point method) in combination with the specially developed relaxation technique is proposed. The developed algorithm allows to calculate marine propulsion shafting bending with taking into account lubrication in all journal bearings and exact form of journal inside bearings, compared to results of most of the publications which consider lubrication only in the aft most stern tube bearing and assume rest of bearings to be represented by points. The calculation results of typical shafting design with four bearings are provided. The significance of taking into account lubrication in all bearings is shown, specifically more exact values of bearings’ reactions, shafting deflections, minimum film thickness and maximum hydrodynamic pressure in the stern tube bearing in case of considering lubrication in all bearings.

Research on MDO of Ship Propulsion Shafting Dynamics Considering the Coupling Effect of a Propeller-Shafting-Hull System

“…The results of the structural mechanics analysis mainly show the relevant performance indexes of shafting alignment, including the load values of each bearing, the load difference between two adjacent bearings and the rotation angle of bearings etc. Poor alignment may lead to abnormal wear of the shafting and cause severe vibration [11]. Using the finite element method, the shafting is discretised into individual finite elements and the force and moment transfer equations between nodes are established.…”

Influence of solid particle contamination on the wear process in water lubricated marine strut bearings with NBR and PTFE bushes

“…However, such agents are not stable enough to achieve a sufficient effect on the surfaces of bearings; an acceptable lubrication is a combination of many contributing factors [3]. Problems related to premature wear of the aft stern bearings are reflected in many publications and are related to their lubrication [4], [5] as well as factors influencing the efficiency of this lubrication, such as vibrations [6], [7] or the dynamics of the shaft movement [8], [9].…”