【作者】 许光辉；

【导师】 黄怀纬；

【作者基本信息】 华南理工大学 ， 固体力学， 2019， 博士

【摘要】 轨道交通以其安全、准点、舒适和运载量大等优势,已成为市民出行的首选交通工具。随着轴重和车速不断增加,车辆与轨道相互作用越来越激烈,由此引发的轮轨动力作用问题变得更加严重。为缓解轮轨动力作用,以减小列车运行引起的低频振动问题,本文采用解析模型分析、结构优化、仿真计算、模型实验和在线测试等多种方法,对地铁轨道系统的动力特性与参数优化进行研究。通过合理设计弹性单元的动力参数、结构型式及耦合关系,研究多层弹性轨道的动力参数优化方法,使得多个弹性单元相互协调工作;实现吸收振动能量和减小振动传递的效果,减缓低频振动放大问题;最后采用实尺寸模型实验和在线测试方法,分析动力特性变化规律,验证解析模型和参数优化结果。本文主要研究内容和成果:(1)从结构动力学角度出发,首先将轨道结构视为具有单层弹性单元的质量-弹簧-阻尼模型,推导得到轨道减振控制指标的解析解,进而分析轨道结构减振与隔振的基本原理。同时在实际工程应用中,利用实测数据研究轨道结构的减振规律,验证轨道解析模型的准确性和可靠性;(2)通过轨道扣件、轨道板、吸振板和弹性单元等结构部件的不同组合,建立多层弹性单元轨道结构的解析模型;利用MATHEMATICA软件编程后进行数值计算,对比分析各种轨道模型的动力控制指标,研究动力特性变化规律及减振特性;(3)基于扣件-吸振板-浮置板轨道动力学模型和结构优化设计的复形法,对三层弹性单元轨道的参数优化进行研究;发挥弹性单元的阻尼特性,使得多个弹性单元相互协调工作,实现吸收振动能量和减小振动传递的效果;优化后的吸振板单元能有效抑制20~40Hz频段的振动成分,可缓解低频动力作用放大问题;最后将复形法和定点同调优化方法进行对比,并采用仿真计算方法对吸振板的减振效果进行验证;(4)按照实际轨道结构搭建一段25米长的实验平台,在预荷载作用下测量得到轨道结构的位移和振动响应;对比分析有/无吸振板、不同扣件刚度和预载荷大小对轨道动力特性影响。实验平台能同时进行轨道动/静态特性实验,为研究减振轨道动力特性提供了可靠的实验数据支撑;(5)选取一段高架段作为实验线路,将原有的轨道结构改造成优化后的扣件-吸振板-浮置板轨道结构;对改造前后线路的轮轨安全性指标、轨道动力学性能、减振降噪性能进行研究分析,验证多层弹性单元轨道动力参数优化方法的可靠性。更多还原

【Abstract】 Rail transit,with its advantages of safety,punctuality,comfort and large transportation capacity and so on,has become the first choice for citizens to travel.Due to the continually increasing axle load and speed,the interaction between vehicle and track is more and more intensive,thus the wheel-rail dynamic interaction become more and more complicated.To alleviate the wheel-rail dynamic interaction,and further reduce the low frequency vibration problem aroused by train operation,the dynamic characteristics and parameters optimization of metro vehicle-track system are studied by analytical model analysis,structural optimization,simulation calculation,model experiment and on-line testing.The parameters of the mass,stiffness and damping of the elastic element are optimized and combined to make the multiple units work in coordination with each other.The effect of absorbing vibration energy and reducing vibration transmission are realized,and the problem of low frequency vibration amplification is alleviated.Finally,the analytical model of theory and the results of dynamic parameter optimization are verified by using track model experiments in real size and the on-line testing method.The main contents and achievements of this paper are as follows:(1)From the point of view of structural dynamics,the track can seemed as an single mass-spring-damp model and the vibration control index are derived,then to analysis the fundamental principles of track vibration attenuation and isolated.Use measured date to study on the rugulation of track vibration attenuation in practical engineering application,and to verified the accuracy and reliability of the analytic model.(2)For dynamic analytical models of damping track,the analytical solutions of dynamic transfer coefficient and dynamic displacement transfer coefficient are formulated and derived.The changing rule and the working mechanism of dynamic characteristics of damping track are analyzed qualitatively by using MATHEMATICA software to carry out numerical calculation.(3)The parameter optimization method of three-layer elastic element track is studied based on the dynamics model of fastener/vibration absorbing plate/floating slab and the complex method of structural optimization design.The damping property of elastic elements brought into play makes many elastic elements working harmoniously with each other.The effects of absorbing vibration energy and reducing vibration transmission are realized,and the optimized vibration vibration absorbing plate can be used to suppress the vibration part of 20~40Hz effectively.The method of complex shape optimization is compared with the method of fixed point homology optimization,and the effect of vibration absorption plate is verified by simulation calculation method.(4)According to the actual track structure,a 25 meter long test platform is built,and the displacement and vibration responses of the track structure are measured under preload.Comparisons are made for the dynamic characteristics of the tracks with and without vibration absorbing plate,under different fastener stiffness and different value of pre-load.The track dynamic/static characteristic experiments provide reliable experimental data for the study of dynamic characteristics.(5)By replacing the original track structure with the one after optimization,i.e.fastener/vibration absorbing plate/floating slab structure,the elevated section of Shanghai Rail Transit Line 2 is selected as the test line.The performance of wheel/rail safety,track dynamics and vibration and noise reduction before and after the revamping are studied and analyzed.Meanwhile,the reliability of the optimization method of track dynamic parameters of multilayer elastic elements are verified.更多还原