面向纵向激励估计的波导模型识别方法研究

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 feasible method 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.