ABSTRACT

Azimuth propulsors are widely used as main propulsion unit on icebreakers and ice-going ships due to high maneuverability and good performance on ice management. Strength of pod, including strut, of ice-classed azimuth propulsors shall be specially considered since they are exposed to sea ice entirely. A brief introduction to ice-pod interaction load cases defined by Class Society's rules and guidance is given in this paper. Ice-pod interaction for an ice-classed azimuth propulsor under different load cases is studied by finite element method. The model of ice-pod interaction is built to analyze the strength of pod. To reflect the reality process, mechanical properties of sea ice shall be fully discussed, such as fragile characteristic, different tensile and compression strength. Under load cases introduced hereinbefore, to analyze the strength of pod due to different factors such as direction of ice inflow, loaded position and impacting speed shall be considered to analyze the influence on pod dynamic response during the collision process. The results are used as design reference for ice-classed azimuth propulsor.

INTRODUCTION

Polar region is rich in natural resources and also natural channels. With the development of the polar exploring, more and more attention has been paid to the polar region. Many countries around the world are focusing on the construction of ice-going ships, especially heavy icebreakers, in order to seize the opportunity of polar region. Azimuth propulsors are widely used as main propulsion unit on icebreakers and ice-going ships due to high maneuverability and good performance on ice management. Compared with traditional direct driven propellers, azimuth propulsor is much more complicated which means the reliability of azimuth propulsor is obviously affected by its strength.

Pod, including strut, is subjected to longitudinal and transverse loads due to ice impact. Sea condition and the direction of inflow lead to different load cases. This paper tries to analyze the strength of pod due to different factors such as direction of ice inflow, loaded position and impacting speed to find out the main factors on pod dynamic response during the collision process.

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