Structural Performance of Swept Cycloidal Propeller Blades Using Coupled Boundary Element and Finite Element Method

Abstract

This study examined the impact of the leading-edge sweep angle on the vibration characteristics of a marine cycloidal propeller (MCP) blade during different ship maneuvering motions using a coupled three-dimensional boundary element method (BEM) and finite element method (FEM) approach. Through this approach, the study captured the interaction between hydrodynamics and structural dynamics, providing a comprehensive understanding of the response of the swept MCP blade. The following ship maneuvers were analyzed: bollard pull, crabbing, crash stop, cruising, and turning circle. During MCP operation, each blade undergoes one oscillation about its own longitudinal axis for each rotation of the horizontal propeller disc. The face and back of the propeller blade interchange during each oscillation. Consequently, the propeller blades are subjected to higher fluctuations in loading because of changes in the angle of attack and inflow velocity at each time instant. This results in complex and unstable fluid dynamics at the blade location. Variations in the sweep angle can profoundly influence the performance of the blade by altering the hydrodynamic loads and structural responses. The impact of the sweep angle is depicted through changes in the displacement, velocity, twisting angle, twisting moment, and von Mises stress of the blade. Furthermore, because of the load fluctuations on the blade, fatigue and load variations in each disc revolution must be considered during the design of cycloidal propellers. Therefore, a preliminary fatigue assessment for each maneuver was conducted. The research provides valuable information into the behavior of swept MCP blades under various loading conditions.

Keywords

Cycloidal propeller / Ship maneuvering / Sweep angle / Boundary element method-finite element method (BEM-FEM) / Fatigue

RIGHTS & PERMISSIONS

Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature