Modeling and Simulation on the Vibration Comfort of Railway Sleeper Carriages

The vibration of the sleeping berth of a railway sleeper carriage has a major impact on the comfort of sleeper passengers. In order to simulate accurately the vibration state of the recumbent passengers, on the basis of the secondary suspension dynamic model of railway vehicles, a human-berth-vehicle spatial vertical coupled dynamic model is established with consideration of the vibration isolation effect of the sleeping berth and the vertical vibration characteristics of the supine human body. Through random excitation of track irregularity on the coupled dynamic model, the vertical vibration responses of a supine human body are examined at different train speeds. The acceleration root-mean-square of head and buttock are weighted twice by body positions and frequencies in succession to get a comprehensive vibration comfort index for the sleeper carriage. Simulation software for the vibration comfort of railway sleeper carriages is developed with Matlab according to the proposed dynamic model. An example of a specific sleeper carriage is given for calculating the vibration comfort index of the upper berth, the middle berth and the lower berth in different carriage positions. This paper provides an effective means of analysis for the layout of carriage berths and the optimization of suspension parameters of sleeper carriages.