Finite Element Analysis Of Groove Structure Of Ship Stern Bearing Under Seawater Lubrication

The ship stern bearing is an important component part of propulsion system in shipstern tube, which is also an important link between internal and external powerexchange, supporting the stern shaft and propeller. Therefore, it is very necessary toresearch influence of different groove structures on mechanical properties of ship sternbearings, based on the Finite Element Method (FEM). Finally, groove structureoptimizations are achieved by comparing different groove structures.Various groove structure stern bearings are analyzed statically by FEM in thispaper. Considering the Elastohydrodynamic Lubrication (EHL) effects, EHL problemsof different strip form stern bearings are solved applying multi-grid method, andanalyzed statically further by FEM. The finite element analysis of established contactcouple models with stern shaft and shaft sleeve is discussed under the contact stress.Finally, based on the results of statical analysis, the sizes of stern bearing groovestructures are optimized in this paper.1) The finite element models of ship stern bearings are established, with differentnumber of spiral grooves, different spiral groove radius size and different spiral angle,and the mechanical property influences of different spiral groove structures on the shipstern bearings are analyzed contrastively, such as stress, strain and elastic deformation,which can provide a reference basis for follow-up optimizations of spiral groovestructure sizes. Moreover, the mechanical properties of three different strip forms withconcave arcs, plants and convex arcs are researched concretely, including thatmechanical property influences of different strip forms, different radius of curvaturewith concave arcs and convex arcs and different groove numbers on the ship sternbearings.2) In considering the effects of stern bearing EHL conditions, stern bearings areanalyzed statically further, with combined FEM and the EHL numerical calculationresults of water film pressures. The influences of water film pressure on stress and strainof stern bearings are investigated, meanwhile the mechanical property influences ofdifferent working loads, different bearing clearances and different thickness of bearinginner ring on the ship stern bearings are discussed.3) According to different spiral groove structures of rubber stern bearings, it isprocessed that static contact simulation analysis considering the nonlinear rubber materials, and verified with the contact stress calculation results of classical Hertztheory. The influences of contact stress, contact conditions and contact deformation ondifferent spiral numbers and different helix angles of stern bearings are analyzedcontrastively.4) Considering the structure size optimizations of the ship stern rubber bearings,three different forms of spiral groove stern bearings are established, such as circular,rectangular and swallowtail. Than, these three models are optimized based on the resultsof finite element static analysis and modal analysis, and the ideal optimal sizeparameters are obtained ultimately.