制动荷载作用下桥上无砟轨道动力响应分析

Dynamic response analysis of ballastless track on bridge under braking load

为研究制动荷载作用下桥上无砟轨道动力响应问题,建立车辆子系统模型和无砟轨道-桥梁子系统模型。根据高速列车制动减速度特性曲线确定列车制动力,利用Hertz理论求解轮轨力,通过交叉迭代法求解有限元数值方程。以4节编组的CRH2型动车组在桥上无砟轨道制动为例,进行系统动力响应分析。研究结果表明:轨道、桥梁结构的纵竖向位移和加速度均逐层递减,梁端处轨道结构的竖向振动比跨中处大;列车制动过程中列车速度逐渐减小引起轨道结构的竖向动力响应也减小;列车停车后,轨道结构和桥梁的纵向位移反向突变、纵向加速度突变,随后都有自由衰减的趋势;列车停车瞬间,列车和桥梁出现纵向最大振动。研究成果可为桥上无砟轨道的设计提供理论支持。

In order to study the problem of dynamic response of ballastless track on bridge under braking load,vehicle subsystem model and ballastless track-bridge subsystem model were established. The train braking forcewas determined according to the braking deceleration characteristic curve of high-speed train and wheel-rail forcewas calculated by Hertz theory, the finite element equation was solved by cross iteration method. Taking a CRH2of four marshalling braking on ballastless track on bridge for example, the dynamic response was analyzed.Calculation results show that, longitudinal, vertical displacement and acceleration of track and bridge structure aregradually decreasing, and the vertical vibration of the rail structure at the beam-end is larger than that of themiddle span. The vertical dynamic response of the track structure caused by the gradual decrease of the trainspeed is also reduced in the train braking process; Longitudinal displacements of track structure and bridge arereverse mutant, longitudinal accelerations are mutation when train stops, then they have a free attenuation trend;train and bridge appears maximum longitudinal vibration at the moment of train stopping. The research results canprovide theoretical support for the design of ballastless track on bridge.