CRTSⅡ型板式无砟轨道非线性屈曲行为研究

Research on Nonlinear Buckling Behavior of CRTSⅡSlab Ballastless Track

针对温度荷载作用下CRTS II型板式无砟轨道上拱屈曲失稳问题,基于有限元软件Abaqus建立考虑初始不平顺和轨道板间摩擦行为的非线性屈曲有限元模型,采用弧长法追踪热屈曲非线性路径并针对不平顺幅值、摩擦性能、轨道自重和轨道刚度等影响因素参数化分析。研究结果表明:初始不平顺的大小影响轨道结构的非线性路径是否存在不稳定阶段,当轨道结构初始不平顺幅值取5 mm时会发生突然屈曲,不平顺幅值取50 mm则不会发生从平衡路径的突然屈曲;轨道板与CA砂浆间的摩擦性能对临界温度几乎无影响,平衡路径的初始分支几乎一致,后屈曲阶段呈发散趋势,安全温度的影响较大;轨道结构自重增加较明显地抑制轨道结构的上拱屈曲,轨道结构自重提高0.2倍,临界温度可提高10℃,安全温度提高近20℃;轨道刚度增加对提高轨道结构抗屈曲能力并不明显。

Aiming at the buckling instability of the CRTS II slab ballastless track under temperature load,a nonlinear buckling finite element model is established based on the finite element software Abaqus,which considers the initial irregularities and the friction behavior between the track plates,and the arc length method is used to track the thermal buckling nonlinearity.The nonlinear path is analyzed by parameterization of the influencing factors such as irregularity amplitude,friction performance,track weight and track stiffness.The research results show that the magnitude of the initial irregularity affects whether there is an unstable phase in the nonlinear path of the track structure;sudden buckling will occur when the initial irregularity amplitude of the track structure is 5 mm,and it will not occur when the irregularity amplitude is 50 mm;the friction performance between the track plate and the CA mortar has almost no influence on the critical temperature,the initial branches of the equilibrium path are almost the same,the post-buckling stage tends to diverge,and the safety temperature has a greater influence;the increase of the weight of track structure significantly inhibits the upper arch buckling of the track structure,the increase of the deadweight of track structure by 0.2 times may result in the increase of critical temperature by 10℃,and the safe temperature by nearly 20℃;the increase in track stiffness does not significantly improve the buckling resistance of the track structure.