Study On Creep Characteristic Of Propeller Shaft In Especial Condition

With more and more research on creep phenomenon, it is demonstrated that room temperature creep widely exists and can do various extent damage to members in many literatures. More attention should be paid to the room temperature creep in some particular circumstance, although the harm extent to material by tiny deformation caused by room temperature creep is less than that by high temperature creep.In traditional opinion, the admissible stress of members is less than the material elastic limit and there is no plastic deformation and crack rupture because of the linear relation of stress and strain within elastic range, so it can't be explained that the early failure phenomenon of members within elastic range. In many literatures, it is demonstrated that the early member failure has a close relations with the tiny plastic deformation appearing in local of the members.Tiny deformation will appear in the local of the propeller shaft of certain ship which is endured an invariableness load, although the shaft stress is within the elastic limit range. The plastic deformation which is changed with time slowly is named room temperature creep. The creep phenomenon is different from the fatigue that the former one has a close relation with time and the latter one has a close relation with the circular times. The shafting structure requires a high invariance of the figure, so even tiny plastic deformation can affect the capability of the shafting. With the same platform, the room temperature creep deformation in the local of the propeller shaft can do damage to the capability of the shaft and induce a loss because of an early failure of the shaft. So it is significative to carry out a research on room temperature creep characteristic of propeller shaft.In this article, based on room temperature creep analysis on propeller shaft, a dynamic and a fatigue analysis on the propeller shaft are carried out. After applying some creep models and using finite element method to calculate the max deformation of the shaft, a comparison of the creep models is carried out. After figuring out the displacement curve of the shaft, some dynamic analysis including a comparison of mode analysis between a bending shaft and a no-bending shaft, excitation caused by deformation and shaft response are carried out. Finally, a fatigue analysis on the shaft is carried out.