Study on Vibration Characteristics of Metro Vehicle System Considering Flexible Wheelset
Metro cars have vigorous interactions between wheel and rail and complex and variable high-frequency vibration characteristics.Based on the rigid multi-body theory,the finite element theory,the modal synthesis method and the car-track coupling dynamic theory,the article studies the influence of the elasticity of wheelsets on the vibration characteristics of cars.Taking B-type metro cars for example,two car-track coupling dynamic models are built up with rigid wheelset and flexible wheelset,the Lagrange method and the Euler method are considered respectively for the kinematic and dynamic solving algorithms for flexible wheelset,the influence of wheel-rail contact spot area,contact stress and wheel-rail force without track irregularity excitation as well as the influence of the flexibility characteristics of wheelset with track irregularity excitation on the wheel-rail force and the journal box vibration acceleration are analyzed.The result shows as follow:the contact spot area of rigid wheelset is smaller than that of flexible wheelset while the contact stress of the former is greater than that of the latter;in addition,for the flexible wheelset,different solving algorithms have different results.If the track irregularity is not considered,the wheel-rail vertical force results of the two models are basically equal,but their wheel-rail lateral forces have a larger difference;if the track irregularity(including short-wave irregularity)is considered,the calculated wheel-rail vertical force of rigid wheelset is greater while the flexibility of wheelset mainly has an obvious inhibiting effect on the vibration caused by short-wave(wave length less than 1m)irregularity;from the result of journal box vibration acceleration,it can be seen that the frequency under which the vibration varies sharply is between 11.50～33.33 Hz and increases sharply with the increase of the excitation frequency,increased by 105.85%for rigid wheelset and only 56.83%～72.26%for flexible wheelset.It turns out that the inhibiting effect of the flexible characteristics of wheelset on the vibration of metro car system is mainly embodied in the track irregularity excitation with a wave length of no more than 2 m.
metro vehiclevehicle-track coupling dynamicsflexible wheelsetwave lengthinhibiting effectnumerical simulation
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