基于频响函数综合的推进轴系动力学建模与支撑结构参数优化分析

针对船舶推进轴系提出了一种基于频响函数综合的子结构方法，考虑了轴承液膜交叉刚度的影响、螺旋桨和推进电机同时激励的工况，分析了在螺旋桨和推进电机激励下的振动响应特性。该方法将耦合系统划分为螺旋桨-轴系、轴承、高弹、推进电机、隔振器和船体子结构，通过二次频响函数综合建立了耦合系统的频响函数表达式。利用该建模方法和灵敏度分析建立了以均方传递力、传递功率流为优化目标的优化模型，针对轴承、隔振器和高弹的刚度参数进行优化。结果表明，基于频响函数综合的子结构建模和优化方法效率高，适合于对支撑结构刚度参数进行优化。对一模型的匹配优化结果表明，轴承和隔振器刚度减小、高弹性联轴器的刚度增加对减小振动传递有利。
Abstract：A FRF-based substructuring method was proposed for dynamic modeling of a propulsion shaft system.The method took into consideration of cross stiffness of oil film,the excitation of both propeller and propulsion machine.The dynamic model of the coupled system was based on two synthesis processes for substructures,i.e.,propeller- propulsion shaft,bearings,coupling,propulsion machine,isolators and hull.FRF-based substructuring sensitivity analysis was employed to evaluate the optimal stiffness of bearings,coupling and isolators under the objective function of mean-square forces and power flow transmitted to the foundation.The proposed method is of great efficiency.For the studied model,the stiffness of the bearings and the isolators should be lowered; the stiffness of coupling should be increased to obtain small vibration transmission.