轨道结构采用隔振措施后对车内低频结构振动和噪声的影响及传递规律研究

In order to reduce the impact on the environment of the rail vehicle operation, such isolation measures as high elastic fasteners, elastic sleepers, elastic supporting blocks, the ballast mats, floating slabs are usually used in track structures. Although the application of these measures reduced the vibration transferred from rail to the foundation, vibration and interior noise of vehicle will be increased, which seriously affect riding comfort. To solve this problem, dynamic mechanical characteristics of different rubber components under different frequencies will be measured; standing wave effect of elastic and visco-elastic elements will be considered; and the modal analysis of vehicle and track system under real running conditions will be studied; dynamic response of vehicle and track system will be analyzed using finite element method combined the multi-body system dynamics; through the establishment of wave equation, the characteristics of vibration wave transmission in the rail and vehicle system will be analyzed; and structure and fluid compartment cavity sound solid coupling system model will be established, such analysis as the vehicle interior noise acoustic modal, acoustic transfer vector (ATV) and vehicle unit and the panel contribution will be carried on. Combined with the comprehensive tests of the vehicle track vibration and interior noise on Tongji University Rail Transit Integral Test Line, transmission law of low frequency vibration and noise from the track structure to vehicle will be put forward. This project research will provide technical support for the integration of vehicle track vibration and noise reduction.

为了降低轨道车辆运行时对环境的影响，通常轨道结构上采用比如高弹性扣件、弹性轨枕、弹性支承块、道砟垫、浮置板等隔振措施。这些措施的应用，降低了钢轨传至基础的振动，但使得车辆振动增加、车内噪声提高，严重影响乘车舒适性。本课题围绕这一问题，对轨道结构的不同橡胶元件进行不同频率下的动态力学特性室内测试，研究弹性和粘弹性元件的驻波效应，以及有载情况下车辆轨道的模态分析；采用有限元法和多体系统动力学相结合的方法分析车辆和轨道动力响应；建立波动方程，分析振动波在车轨系统传播的特点；并建立车室结构与空腔流体的声固耦合系统模型，进行车辆声学模态、车内噪声、声学传递向量（ATV）和车辆单元及板件贡献量分析。结合在同济大学轨道交通综合试验线上进行不同轨道隔振措施的车轨振动和车内噪声试验，研究由轨道结构隔振引起的车内低频结构振动和噪声的传递规律，为车辆轨道减振降噪一体化提供技术支撑。

本研究通过建立A型地铁车辆-无砟轨道的刚柔耦合模型、考虑车体振动的流固耦合模型，结合现场实验，分析采用不同刚度的扣件道床时车内噪声的分布规律和机理。结果发现：1. 扣件的动刚度随动荷载变化，随振幅增大而减小，随频率增大而增大。同时压缩型扣件橡胶刚度非线性程度明显高于剪切型扣件；2. 当轨道的主要减振措施是扣件时，行车状态下轨道第一主振频率随着扣件刚度的增大而增大，其中f_1/f_2 ≈√(k_1/k_2 )；3.实验和仿真结果表明，车体振动以50Hz以内低频振动为主，车辆通过弹性扣件地段时比普通扣件地段明显剧烈；4. 利用波动理论，给出了弹性介质和粘弹性介质中的波动方程、传播速度和波动能量的表达式。5. 车内噪声频谱呈宽频带分布，噪声能量都主要集中在20-500Hz的低频率范围内；速度相同时，各测点的声压级弹性扣件地段比普通扣件地段略大，差值在3dB（A）左右；6. 车体空腔声学模态频率在21.731Hz、29.469Hz和35.732Hz时，与车体结构的特定模态振动频率接近，车内声场将会产生耦合现象。7. 通过声品质分析，列车车内各噪声测点的响度值均大于25sone，并不能满足人体的乘坐舒适性要求。列车通过弹性扣件区间的响度值比普通扣件区间大1～3dB。