Research On Rotational Vibration Characteristics And Unbalanced Response Of Paddle-shaft System

The rotary vibration of the ship's oar-shaft system is an important factor affecting the normal operation of the ship shaft system.The eccentric mass is the main cause of the rotary vibration of the paddle-shaft system.According to the specific equipment parameters,the finite element model of the paddle-shaft system is established.The inherent characteristics of the system are studied.The influence of the support stiffness and the support position on the natural frequency of the system and the influence of the positive torque and the rotation damping on the critical speed are analyzed.Indicating that the stiffness of the propeller position near the propeller,the impact of the low-order natural frequency of the paddle-shaft.In this paper,the eccentricity of the eccentric mass is applied to the imbalance quality,and the influence of the eccentric mass on the unbalanced response is studied.The results show that the larger the eccentricity is,the larger the amplitude of the system is,and the amplitude of the system changes linearly with the size of the eccentricity.The phase response curves of the eccentric mass are basically coincident and the change of the eccentricity has no effect on the phase.The influence of eccentricity on the unbalance response of rigid and flexible axes is analyzed under the critical speed.The results show that the amplitude of the rigid and flexible axes changes with the frequency before the first order critical speed,but the amplitude of the flexible axis is obviously larger than that of the rigid axis.Therefore,when vibration analysis is required for a shaft having a high vibration control requirement,it can be simply simplified as a rigid shaft at a critical speed,but it is necessary to analyze the vibration of the shaft based on the actual rigidity.