温度力作用下纵连式轨道结构振动特性及稳定性研究

Vibration Characteristics and Stability of the Longitudinal Coupled Track under Temperature Force

以CRTSⅡ型板式无砟轨道为例,建立纵连式轨道结构垂向振动模型,利用有限单元法求解了有初始上拱时轨道板在纵向温度压力作用下的自振频率,并基于结构稳定性分析的动力准则研究轨道结构在纵向温度压力作用下的垂向稳定性。分析温度梯度、假缝和基础刚度对轨道板自振频率和垂向稳定性的影响。研究表明,纵向温度压力会导致纵连式轨道结构自振频率的下降,当温升接近于其失稳的临界温度时,其低阶自振频率趋近于0 Hz;温度梯度会降低轨道板的自振频率,其中正温度梯度的影响较负温度梯度更为明显;假缝会降低轨道板的自振频率,但影响较小;基础刚度越小轨道板的自振频率越小;温度梯度、假缝和基础刚度对纵连式轨道结构失稳的临界温度均影响有限。

Taking the CRTS Ⅱ slab track as an example, the finite element model of vertical vibration is established, the vibration frequency of the longitudinal coupled track with initial upwarp under longitudinal temperature force is solved by finite element method, and the vertical stability of the track structure under the longitudinal temperature force is studied based on the dynamic criteria of structural stability analysis. The effects of temperature gradient, dummy joint and foundation stiffness on the vibration characteristics of track plate are analyzed. The results show that the longitudinal temperature force will lead to the decrease of the natural frequency of the track structure; When the temperature is close to the critical temperature of instability, the natural frequency approaches to 0 Hz; The temperature gradient will reduce the natural frequency of the track structure, in which positive temperature gradient is more obvious than negative temperature gradient. Dummy joint will reduce the natural frequency of the track plate, but the impact is small. Temperature gradients, dummy joint and base stiffness have little effect on the critical temperature.