The Study Of Fatigue Crack Propagation Of The High-power Marine Propeller Based On XFEM

The marine propellers that equip large offshore platform are usually dozens of tons in weight and up to ten meters in diameter with complex surface. During their services, the propellers would provide tremendous thrust and bear alternating impact from the seawater. In addition, the electrochemical corrosion and cavitation of the seawater would accelerate the damages of the propellers which will eventually lead to failure. These characteristics undoubtedly are posing a new challenge to the designer of marine propellers.This article investigated and analyzed the failure that happened in between 1960 s and 1970 s and the findings suggest that the failure is mainly caused by the fatigue crack propagation. Then this article established a simulation model based on the Leaner Elastic Fracture Mechanics(LEFM) and Extended Finite Element Method(XFEM). The CFD method was implemented to obtain the hydrodynamic loads of advance ratio from 0.1 to 0.9 with the advance speed being fixed on 1m/s using the propeller model provided by CSIC 461. By analyzing the maximum stress point, the position for the crack can be determined. Finally, with the help of FEM software ABAQUS, the fatigue life of this propeller was studied at two different operating points.In conclusion, if this marine propeller is operating under its maximum rotational speed, no matter how harsh the operating condition is, the propeller would not fracture whereas if the maximum rotational speed is increased, there will be a tendency of failure under some circumstances.