新型弹性侧支撑长轨枕式减振轨道结构力学特性研究

Mechanical characteristics of new type long sleeper damping track structure with elastic lateral support

新型弹性侧支撑长轨枕式减振轨道和既有轨枕式减振轨道的弹性支撑方式不同,重点对新型弹性侧支撑长轨枕式减振轨道力学特性和关键参数展开研究。在轮载作用条件下,对比分析两种减振轨道的应力分布情况,找出道床的应力集中区域及最不利位置,研究载荷施加在新型弹性侧支撑长轨枕式减振轨道不同位置时部件的应力分布特征,并对道床的减振特性加以研究。针对荷载作用于轨枕正上方时的最不利位置,进行道床承轨槽折角处的应力分布分析,以及减振轨道整体道床的配筋设计与检算。采用试验与仿真相结合的方发,研究了侧支撑式弹性垫板的厚度、空间倾斜量和材料硬度对轨枕节点动刚度和垂向最大位移的影响。研究结果表明,新型弹性侧支撑长轨枕式减振轨道道床的最大应力出现在承轨槽两侧下部靠近折角的区域,与既有轨枕式减振轨道的最大应力出现在承轨槽底部中间区域截然不同,且减振效果较显著。道床结构参考既有纵向承轨台整体式道床的配筋方案可以满足受力要求,承轨槽两侧下端折角处不会开裂。侧支撑式弹性垫板的厚度、空间倾斜量和材料硬度是影响新型弹性侧支撑长轨枕式减振轨道节点动刚度的三个关键,其中厚度和材料硬度的变化对节点动刚度的影响较大,增加侧垫厚度,降低材料硬度使节点动刚度降低,载荷-位移滞回曲线的面积增大,消耗的振动能量更多;空间倾斜量的影响较小,与节点刚度之间存在正比例变化关系;在三个关键参数的研究范围内取值可以获得满足规范要求,并具有不同减振等级的节点动刚度。

Elastic support forms of new type elastic laterally supported long sleeper damping track are different from those of the existing sleeper damping track.Here,mechanical characteristics and key parameters of the former were studied.Firstly,under the condition of wheel load,stress distributions of the above two damping tracks were analyzed contrastively,stress concentration areas and the most unfavorable position of track bed were identified,stress distribution characteristics of components were studied when load was exerted on different positions of the new type damping track,and damping characteristics of track bed were studied.Secondly,for the most unfavorable position when load acting directly above sleeper,stress distribution analysis was performed at bend angle of track bed track support groove,and reinforcement of damping track integrated track bed was designed and checked.Finally,a combination of test and simulation was used to study effects of thickness,spatial inclination and material hardness of laterally supported elastic pad on node dynamic stiffness and vertical maximum displacement of sleeper.The results showed that the maximum stress of the new type damping track bed appears in areas near bend angles at lower parts of both sides of track support groove,it is completely different from the maximum stress of the existing sleeper type damping track appearing in middle area of bottom of track support groove,and its damping effect is more significant;the reinforcement scheme of the new type track bed structure with reference to the integrated track bed of the existing longitudinal track support platform can meet stress requirements,and places at bend angles of lower parts of both sides of track support groove can’t have cracking;thickness,spatial inclination,and material hardness of the laterally supported elastic pad are 3 key factors affecting node dynamic stiffness of the new type damping track,changes of thickness and material hardness have a larger impact on node dynamic stiffness,increase in thickness of side pad and decrease in material hardness can reduce node dynamic stiffness,increases in area of load-displacement hysteresis curve can dissipate more vibration energy;effects of spatial inclination are smaller,and there is a positive proportional relation between spatial inclination and node stiffness;choosing these 3 key parameters within their studied ranges can achieve node dynamic stiffness meeting the specification requirements and having different vibration reduction levels.