Reliability of super-slope bridge-rack system on rack railway
Reliability of super-slope bridge-rack system on rack railway
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DOI：
10.1080/23248378.2023.2248996
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发表时间：
2023-08
影响因子：
4
通讯作者：
Zhaowei Chen;Lang Wang;Shihui Li;Mi’ao Yuan;Qianhua Pu;Zhihui Chen;Jizhong Yang
中科院分区：
文献类型：
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作者：
Zhaowei Chen;Lang Wang;Shihui Li;Mi’ao Yuan;Qianhua Pu;Zhihui Chen;Jizhong Yang
在大坡度铁路桥上运行时（特别是在温度荷载作用下），由于桥与架之间结构连续性的差异，桥端结构变形远大于架端结构变形，大大增加了架端局部应力，损坏了架端及扣件，严重威胁了运营的可靠性。为研究温度载荷和特大坡桥与齿条非线性动力相互作用对齿条可靠性的影响，考虑齿轮齿条系统的非线性动力啮合特性和轮轨系统的非线性动力接触特性，建立了详细的车-架（轨）-桥耦合动力学模型。然后进行现场试验，获得了齿轨铁路的基本动力学行为，并验证了所建立的数值模型。在此基础上，研究了温度载荷、齿轮齿条啮合特性和轮轨接触特性对齿条-桥梁系统变形和内应力的影响。最后，提出了保证大坡度桥上铁路网架结构可靠性的方法。结果表明，在不同荷载作用下，桥缝附近的网架变形与桥梁变形高度不一致，网架和螺栓的内应力超过了相关规范的限值，严重威胁网架结构的可靠性。齿条最大应力为898 MPa，超过了齿条的抗拉强度。扣件与齿条、扣件与轨枕间螺栓的最大剪应力分别为1510 MPa和656 MPa，超过了螺栓的抗剪强度。根据本文的计算结果，建议采用弹性扣件连接齿条和轨枕，可有效降低齿条和螺栓的应力，提高齿条结构的可靠性。
During the operation of rack railway on super-slope bridges (especially under temperature load), structural deformation of bridge-end is much larger than that of rack due to the difference of structural continuity between bridge and rack, which greatly increases local stress in rack, damages rack and fastener, and seriously threatens the operation reliability. To investigate the reliability of rack caused by temperature load and nonlinear dynamic interaction between super-slope bridge and rack, a detailed vehicle-rack(rail)-bridge coupled dynamic model is established with consideration of nonlinear dynamic meshing behaviour of gear-rack system and nonlinear dynamic contact behaviour of wheel-rail system. Then a field test is performed to obtain the basis dynamic behaviour of rack railway and validate the established numerical model. On this basis, the effects of temperature load, gear-rack meshing behaviour and wheel-rail contact behaviour on deformation and internal stress of rack-bridge system are investigated. Finally, the method to guarantee the structural reliability of rack railway on super-slope bridge is proposed. Results show that rack deformation nearby bridge gap is highly inconsistent with bridge deformation subject to different loads, and the internal stresses in rack and bolt exceed limit values written in relevant code, which seriously threatens the reliability of the rack structure. The maximum rack stress is 898 MPa, which exceeds the tensile strength of rack. The maximum shear stresses of bolts between fastener and rack and between fastener and sleeper are 1510 MPa and 656 MPa respectively, which exceed the shear strength of bolts. According to the calculation results in this paper, elastic fastener is suggested to be used to connect rack and sleeper, which can effectively reduce stress in rack and bolt, and improve the reliability of the rack structure.