Preliminary Study On Fault Mitigation Of Marine Shaft Cracks

As one of the key components of the marine power system, shafting willgenerate many types of microscopic internal defects and fatigue problems in thesevere working environment, and gradually evolve into macroscopic crack. It is likelyto fracture and directly affect the safety of the ship. So research and analyze theinfluence of crack on shafting vibration characteristics, the fracture characteristics ofcrack and the influence factors of crack propagation rate to improve the security andreliability of the ship has the vital significance.This thesis utilizes the finite element software ANSYS to study the vibration andfracture characteristics of the flat and axis containing a crack, and the effects ofdifferent conditions on the fatigue crack propagation rate of optical axis. Main workcontent is as follows：(1)The finite element software ANSYS is utilized to establish a two-dimensionalflat finite element simulation model containing a penetrating crack, analyse thefracture characteristics of this model, study the effects of finite element methodsdivisions for the calculation result and lay the foundation for the subsequent researchwork.(2)The software ANSYS is utilized to establish a three-dimensional flat finiteelement simulation model containing a crack, study the fracture characteristics ofthis model and provide support for establishing axis model containing cracks.(3)The finite element software ANSYS is utilized to establish an axis finiteelement simulation model containing a crack, analyse the vibration characteristics ofthis model containing crack before and after, obtain the first four order vibrationfrequency and study the influence of different crack length on the axis vibrationcharacteristic.(4)Study the fatigue fracture characteristics of axis containing a crack, discussthe factors influencing the fatigue crack propagation rate, and obtain the effects ofload and speed on the fatigue crack propagation rate of axis. Provide theoreticalfoundation for marine machinery crack fault mitigation.