弹性螺旋桨-轴系建模及振动特性的解析方法研究

为考虑螺旋桨自身弹性对桨-轴系统振动特性的影响,建立了一套基于Timoshenko梁理论的解析方法。将螺旋桨、轴系均用Timoshenko梁建模,结合桨叶与轴系连接处的协调条件及其边界条件,给出系统横向、纵向自由振动的控制方程;在同有限元结果对比表明本方法具有良好精度基础上,分析了桨叶弹性对系统模态的影响及桨-轴系统的力传递特性。研究表明:桨-轴系统的模态振型中螺旋桨叶片和轴系的弹性变形同时发生且相互影响,叶片弯曲模态会加剧轴系振动;作用于桨叶的激励引起的桨-轴系统轴承处的纵向传递力被桨叶弯曲和轴系纵振两阶模态显著放大,而横向传递力主要由桨叶及轴系的弯曲模态控制。

The analytical solution of the modeling and vibration characteristics of elastic propeller-shaft

Abstract:In order to consider the influence of the propeller elasticity on vibration characteristics of a propeller-shafting system, an analytical solution was developed based on the Timoshenko theory.The propeller blades and shaft were all modeled by a Timoshenko beam.According to the continuous condition of joint and boundary condition, the control equation of the transverse and longitudinal free vibration of system was deduced.Contrasted the solution of a finite-element model and the analytical solution, they were in good agreement.The effect of propeller elasticity on the mode and force transmission characteristics of the system was explored.The results show that the deformation of both the blades and shafting of the true elastic propeller-shafting system can be seen and their vibration is coupled.The bending mode of blades can aggravate the vibration of shafting.The longitudinal force transmitted by bearing was amplified by the bending mode of propeller and longitudinal mode of shafting, while the transverse force was mainly controlled by bending modes of propeller and shafting under the excitation at the blade.