Improved Study on the Fluctuation Velocity of High-Speed Railway Catenary Considering the Influence of Accessory Parts

To improve the prediction accuracy of the wave propagation velocity of high-speed railway catenary, a method for identifying the fluctuation velocity of catenary (FVC) considering the influence of the accessory parts of catenary (APC) is proposed. Based on the classical Bernoulli-Euler beam vibration model, the single Euler beam model under ideal conditions is improved considering the influence of the inertial forces exerted by accessory parts on the catenary. The calculation expression of FVC considering the influence of APC is deduced according to the theory of elastomer vibration mechanics. The key parameters α and β that affect the FVC are obtained, and the relation curves between the fluctuation velocity and the key parameters α and β are analyzed respectively. Through the fluctuation velocity test for the actual catenary, the theoretical fluctuation velocity of contact wire considering the influence of APC are compared and verified with the measured fluctuation velocity. Research results show that the relative error between the theoretical fluctuation velocity obtained from the modified fluctuation velocity expression of contact wire considering the influence of APC and the measured fluctuation velocity is less than 10%. Compared with the fluctuation velocity theoretical formula based on the string/cable and Euler beam theory, the modified expression of the fluctuation velocity of contact wire (FVCW) is more accurate in identifying the FVCW, and the recognition accuracy is increased by 3.75%, which verifies the accuracy of the recognition method and provides a more accurate theoretical basis of fluctuation velocity for designing the structural parameters of catenary.