面向纵向激励估计的波导模型识别方法研究

Research on waveguide model recognition method for longitudinal excitation estimation

对于舰船推进轴系的螺旋桨激励,由于其工作环境和结构条件的限制,很难在实际工况下进行直接测量。通过测量轴系的振动响应对螺旋桨激励进行估计是一种可行的方法。本文根据激励反演理论,从推进轴系的一般结构形式出发,提出了适用于由轴系振动响应估计螺旋桨激励的理论模型。由等截面均匀轴入手,通过轴段的波动解来分析纵向振动;结合边界条件,推导了波幅系数递推关系,进而建立了推进轴系纵向振动的一般波导模型。根据振动响应和建立的波导模型来识别波幅系数,并反演螺旋桨纵向激励。将模态法与波导法相结合,对一般的变截面非均质轴段的波导模型和轴段间波导传递关系进行了论证。结果表明,模态法与波导法结合,可作为一般方法,根据实测振动响应对复杂轴系结构的波导模型进行识别。

The propeller excitation of the ship propulsion shafting is difficult to perform direct measurement under actual working conditions due to the limitation of its working environment and structural conditions.It is a feasiblemethod to estimate the propeller excitation by measuring the vibration response of the shafting.Based on the theory of excitation inversion,a theoretical model suitable for estimating the propeller excitation from the vibration response of the shafting from the general structural form of the propulsion shafting,is proposed.Starting from the uniform axis of equal section,the longitudinal vibration is analyzed by the wave solution of the shaft section.Combined with the boundary conditions,the recursive relationship of the amplitude coefficient is derived,and then the general waveguide model of the longitudinal vibration of the propulsion shaft is established.The amplitude coefficient is identified based on the vibration response and the established waveguide model,and the longitudinal excitation of the propeller is inverted.Through the combination of the modal method and the waveguide method,the waveguide model of the general variable section non-homogeneous axial section and the waveguide transmission relationship between the shaft segments are demonstrated.The results show that the modal method combined with the waveguide method can be used as a general method to identify the waveguide model of complex shafting structure based on the measured vibration response.