Dynamic Performance Simulation And Research Of Flat Car Based On Flexible Body

Container transport is a modern method of transportation; it is the main trend of railway transportation. High-speed, heavy-load, lightweight has become the theme of development of China’s railway rolling stock; the impact of these changes on the dynamic performance of the vehicle system can not be ignored. Conventional vehicle system dynamics performance research usually consider the body as a rigid body, under the conditions of high-speed operation of the vehicle, the impact of elastic deformation of car body on vehicle system dynamic performance should not be ignored, especially on the flat car, because the flatcar body has smaller vertical stiffness.In the line dynamic tests, vertical acceleration of some loaded depressed center flat vehicle on center plate area exceed allowable criteria frequency, whereas acceptable on empty or other loaded gondola and box vehicles. For this phenomenon, the paper selected the NX17container flat car, and set up the multi-body model of the vehicle system as the research object, the body is considered as the flexible body and rigid-flexible coupling model.Firstly, according to GB/T5599-1985, the two kinds of models of the vehicle system dynamics simulation analysis results show that the stability on straight way of rigid-flexible coupling model is better than the multi-body model, considering the effect of the structural flexibility, lateral and vertical vibration accelerations are both larger than these of the rigid model, there will be more noticeable vibration at high speed. Considering curve passing, security indicators of both models meet the standard; rigid-flexible coupling model’s indicators are slightly larger than the multi-body model in all conditions. It will be more safe when consider the structural flexibility in dynamic performance research of vehicle system, it should not be ignored when the conditions are very strict.For the phenomenon of car body vertical vibration acceleration is too large, the paper analyzes the vertical vibration acceleration spectrum, taking into account the impact of the rail head irregularity periodic excitation on the body vertical vibration response. The analysis results show that, when considering the body as elastic structure, more impact force transmitted from wedge aced on center plated of loaded depressed center flat vehicle, on which few load is applied, therefore abnormal vertical acceleration is induced. Track joint irregularity mainly causes the high-frequency vibration of the vehicle body; this frequency and the frequency of car body vertical response on specific conditions are in the same range, so the vibration of the vehicle body is more obvious.This article uses the rigid-flexible coupling method to explore flexible deformation’s effects on the dynamic performance of the vehicle system and analyzes the cause of large vertical acceleration of flat car body, providing a useful reference for the practical application of the flat car.