铁路轨道胶垫频变与温变动力非线性的轮轨空间耦合时变频响特征研究

In allusion to the confusing broadband vibration-transmission mechanism, the unsatisfactory vibration-reduction effect and the increasingly negative impact of polymer rubber pads in Chinese railway track, firstly it is necessary to scientifically test and mathematically express the frequency-dependent and temperature-dependent nonlinear dynamic characteristics of track pads. Secondly, the general symplectic model of the time-dependent nonlinear pseudo-excitation random vibration of vehicle-track coupling spatial system is established based on symplectic method of infinitely long periodic structure, periodical pseudo-steady state method, symmetric condensation method, pseudo-excitation and its application experience in solution of the material nonlinear random vibration problem. Thirdly, with application of the test results and the general symplectic model, the influence of the frequency-dependent and temperature-dependent nonlinear dynamic characteristic of polymer rubber track pads on the time-dependent frequency-domain responses of vehicle-track coupling spatial system is investigated, and the mechanism of the frequency-domain vibration transmission and the resonance between vehicle and track with polymer rubber pads is also discussed. According these research conclusions, the optimization principle and the design method of the stiffness, the damping and their matching relation of the polymer rubber pads in Chinese different-level railway track are proposed to scientifically correct the main curve graph of these pads. Finally, a railway test line is selected to compare the practical effects before and after application of the improved polymer rubber track pads, in order to further verify the reasonability and the accuracy of the theoretical suggestions. Besides, the corresponding research achievements can also normalize the intermingled market of polymer rubber track pads and provide the reasonable optimization design of their dynamic parameters.

针对我国铁路轨道高分子胶垫宽频传振机理不清、减振降噪效果不理想及其负面作用日益凸显的现实问题，拟将在轨道高分子胶垫频变、温变特性的测试实验与科学表征基础上，借鉴无穷周期链式结构的辛数学方法、周期拟稳态求解法、虚拟激励法及其在材料非线性随机振动求解问题中的应用经验，创建车辆-轨道空间耦合时变非线性随机振动虚拟激励的扩展辛分析模型，用以探明温/频变轨道胶垫对轮轨空间耦合时变随机振动频域统计特征的影响规律，并重点研讨高分子胶垫轨道结构的轮轨频响传布机制与轮轨共振机理。据此，提出我国不同线路等级下轨道结构不同部位高分子胶垫温/频变刚度、阻尼及其匹配关系的优化原则与设计方法，科学地修正轨道胶垫动参数的主曲线图谱，并结合实际工程，比较轨道胶垫改良前后的实际效果，验证理论研究的合理性与准确性。相关研究成果可用以规范目前良莠不齐的轨道高分子胶垫市场，同时也可为轨道高分子胶垫动参数的合理优化指明正确的方向。

本文以我国高速无砟轨道扣件弹性垫板为研究对象，采用配备温控箱的万能试验机，测试了弹性垫板在不同频率/温度/振幅以及预压条件下的动态力学行为；并基于温频等效原理与WLF方程，应用分数阶Zener模型以及Berg模型理论表征了弹性垫板真实动态黏弹塑性力学特征。为探明高速铁路无砟轨道轮轨空间耦合时变频响特征研究提供准确科学的计算参数。.基于无穷周期结构的辛数学方法以及高频波谱单元法，提出了一种辛数学与波谱单元法混合的高效算法（SM–SEM混合算法），计算分析了钢轨扣件弹性垫板频变动参数影响下钢轨垂向振动谐响应的位移导纳，并修正了钢轨扣件弹性垫板动参数的选取方法；基于传统车辆轨道耦合系统动力学理论，研究建立了钢轨扣件弹性垫板宽频、宽温、宽应变动态力学服役性能的科学评价体系；采用频率波数域模型（基于无穷周期链式结构辛数学理论与高频波谱单元理论的车辆无限长钢轨扣件垂向耦合动力学模型）及其虚拟激励算法，计算分析了钢轨扣件弹性垫板频变动力性能对轮轨垂向耦合振动特性的影响；采用时间空间域模型（车辆有限长钢轨扣件垂向耦合动力学模型）及其数值积分算法，计算分析了钢轨扣件弹性垫板幅变/温变/预压动力性能对轮轨垂向耦合振动特性的影响；通过建立扣件系统三维实体非线性有限元模型，研究评价了弹性垫板频变刚度特性对不同安装状态下弹条固有频率特征的影响。.本项目通过现场调研，试验测试和理论分析，本项目形成了一系列具有指导工程设计的理论成果，对我国高速铁路轨道高分子材料精细化设计与评价具有一定参考价值。