轴系运行工况对轴系-基座-壳体耦合振动影响研究

螺旋桨推进轴系与船体艉部耦合振动是制约船体减振降噪的重要因素,研究其成因机制和影响因素对于识别和有效控制船体艉部振动和噪声具有重要意义。故从轴系运行状态着手,基于有限元转子动力学理论,对轴系-基座-壳体耦合振动影响因素如轴系运行工况、校中状态及激振力等进行分析。在直线校中状态下,选定轴系四种运行工况,运用雷诺方程计算各工况下支撑轴承压力分布及八动力特性参数,引入轴承润滑油膜和水膜刚度和阻尼矩阵,将各支撑轴承离散成多点支撑,在此基础上建立轴系-基座-壳体系统有限元模型,计算多激励下系统动力响应,采用有限元功率流分析各工况下支撑轴承传递特性对系统耦合振动的影响。结果表明,不同工况下轴承支撑特性会导致系统耦合振动特性不同,经轴系传递到壳体上的功率流也会产生相应变化,最终将会引起不同的辐射噪声。

Shafting Operating State Effects on Shafting-Base -Hull Coupling Vibration

Propeller-shaft systems and hull stern coupling vibration is the most important factor for hull vibration and noise reduction. To find out the basic excitation mechanism has important significance to the recognition and efficient control of vibration and noise. According to the operating state of shafting, the factors such as operating conditions, alignment state, and exciting force which have an effect on shafting-base-hull coupling vibration are based on FEM rotor dynamic theory to analysis. Under the straight alignment, the oil and water film 8-dynamic coefficients are calculated by Reynolds equation for four shafting operating states, the stiffness and damping matrices of single multipoint support bearing are established, the FEM of shafting-base-hull is established. Based on this, alignment state effect on shafting-base-hull coupling vibration is analyzed by FEM power flow, according the result of system dynamic response. The result shows that different operating states can induce different internal stress, different bending deformation and then the change of bearing characteristic. With the corresponding, the power flow passed hull can change which induce system coupling vibration and cause different noise.