Research On Some Matters Of Locomotive Dynamics

With the purpose of providing a systematic study on locomotive dynamics, the paper looks into the bogie structure of China’s AC drive locomotive, as well as the locomotive stability amid nonlinear transverse movement; The paper analyses the methods applied in the study on locomotive dynamics:including irregularity detection using sensitive wavelength components as input, synthetically multi-objective method for wheel-rail profile alignment, and optimum scheme using dynamic parameters in orthogonal experiment, etcetera; The paper studies issues on wheel-rail relation of AC drive freight locomotive:including the influence of wheel metal type to wheel-rail contact stress, and the impact of sand, water and other media to wheel-rail adhesion; The paper studies the safety performance of the slave locomotive of heavy haul train with the consideration of the influence of longitudinal component of the transverse force.Over the past few years, China has launched a large scale campaign, bringing 11 types of Hexie AC drive locomotives into service, namely HXD1, HXD2, HXD3, HXD1B, HXD2B, HXD3B, HXD1C, HXD2C, HXD3C, HXN3 and HXN5. Despite such accomplishment, the country still falls short in the comparative study on bogie structure of the locomotives mentioned above. The paper endeavors to categorize and then comparatively analyze the cantilever arrangement of driving gear(s), the simply-supported structures at the outer edge and at both ends of driving gear(s), and principles of operation of the structures mentioned above. Such effort paves the way for the improvement of bogie structure design and the establishment of dynamic model.Locomotive stability amid transverse movement stands as an important topic in dynamic study. Although linear critical speed has always been used as the parameter, insurmountable difficulties arises in practice. The paper offers the diagram that depicts, in a detailed and comprehensive manner, the critical moments of locomotive stability amid operation. On this basis, it works out the method of numerical value bifurcation accordingly and proposes the Hopf bifurcated speed at the sub-critical moment as the replacement of linear critical speed to reflect the speed limit of locomotive.Correct input of irregularity, aligned wheel-rail profile and proper optimization of related parameters concerned shall be guaranteed for the dynamic analysis. For this purpose, the paper offers irregularity detecting method using sensitive wavelength components based on China’s track maintenance standard, synthetically multi-objective method of wheel-rail profile alignment, and the orthogonal preferred selection of dynamics parameters based on orthogonal experiment.Compared with DC drive locomotive, AC drive freight locomotive faces two important tasks-to minimize wheel-rail wear and to improve wheel-rail adhesion. For that to happen, the paper elevates the wheel solidity and strength index via simulation analysis, which helps enhance the deformation resistance (plastic) of the wheel and extend its longevity. Alongside that, the paper carries out experimental study to identify the optimized sanding volume, improving wheel-rail adhesion and overcoming the negative impact of sanding.The running safety of the slave locomotive (in the middle) in combined heavy haul train is largely decided by the longitudinal component of the transverse force. In terms of the running safety of slave locomotive (in the middle of heavy haul train), the paper looks into type-100, type-101 and type-102 coupler structures and studies their influence on train’s force transmission and resolution in the longitudinal direction. At the same time, the paper simulates the safety performance of the slave locomotive (in the middle) under the influence of longitudinal force and its transverse component and conducts running tests accordingly.