地铁基础减振地段钢轨异常波磨 治理方案研究

针对地铁线路产生的钢轨异常波磨问题,调研了某地铁线路的钢轨波磨情况以及基本特征,对轨道刚度、 钢轨廓形、轨距以及轨道动力特征进行测试,提出钢轨异常波磨的治理思路,并对波磨治理效果进行跟踪测试, 提出既有线以及新建地铁线路钢轨波磨的治理以及预防方案。研究表明：地铁钢轨波磨较为严重,波长在 25～ 100 mm 之间;轨道垂向刚度、横向刚度整体较弱,钢轨位移大,保持轨距能力差,轮轨关系恶化,在特定频段 范围内轮轨振动加剧,从而引起钢轨波磨的产生和发展。通过更换扣件及垫板、轨道精测精调、钢轨打磨措施可 以使车内噪声降低 5～10 dB,轨面不平顺显著降低,打磨周期延长至 1 倍以上;既有线路可通过“细调查、调参 数、精维修、动态检查”治理钢轨波磨,新建地铁线路应在规划、设计、运营维护、动态验收阶段严格把关,合 理采用减振轨道,避免钢轨异常波磨的产生和发展。     

地铁车辆部件隔声性能指标研究

地铁车辆部件作为重要噪声传递路径,其隔声性能对车内噪声有重要影响。文章以我国某型地铁车辆部件为研究对象,通过建立车内噪声预测分析模型,研究了车辆部件的隔声性能指标。结果表明,改变车门、车窗和风挡的隔声量,对车内噪声的抑制效果最显著。     

汽车天窗玻璃密封条开启、关闭异响问题的研究

汽车天窗即作为通风、采光的汽车功能部件,同时也是直接能被客户感知的部件,汽车天窗的运行时平稳、安静能提高乘员的舒适性。本文从机理上对天窗打开、关闭过程中的密封条摩擦振动进行了分析,并提出了部分影响、控制因素。设计、开发及验证阶段注意这些因素,即可避免出现这样的问题,稳定天窗总成的质量。     

Suspension system state estimation using adaptive Kalman filtering based on road classification

This paper provides a new method to solve the problem of suspension system state estimation using a Kalman Filter (KF) under various road conditions. Due to the fact that practical road conditions are complex and uncertain, the influence of the system process noise variance and measurement noise covariance on the estimation accuracy of the KF is first analysed. To accurately estimate the road condition, a new road classification method through the vertical acceleration of sprung mass is proposed, and different road process variances are obtained to tune the system’s variance for the application of the KF. Then, road classification and KF are combined to form an Adaptive Kalman Filter (AKF) that takes into account the relationship of different road process noise variances and measurement noise covariances under various road conditions. Simulation results show that the proposed AKF algorithm can obtain a high accuracy of state estimation for a suspension system under varying International Standards Organisation road excitation levels.     

An evaluation framework for traffic calming measures in residential areas

The paper evaluates the effectiveness of various traffic calming measures from the perspectives of traffic performance and safety, and environmental and public health impacts. The proposed framework was applied to four calming measures – two types of speed humps, speed tables, and chicanes – to demonstrate its usefulness and applicability. A field experiment using probe vehicles equipped with global positioning system devices was conducted to obtain vehicle trajectory data for use in more realistic simulations. In addition, a recently developed vehicle emissions model was used for more accurate evaluation of environmental and public health impacts. The results show that chicane is better than the other types of traffic calming measures considered, except in terms of vehicle emissions.     

Options for reducing noise from roads and railway lines

The fundamental noise generation mechanisms of road and rail vehicles are discussed with attention to noise abatement measures. Based on an evaluation of publicly available tire noise data and the European road traffic noise emission model CNOSSOS, it is shown that on the road side there is a significant noise reduction potential in the usage of low-noise tires. From a three months measurement campaign a noise model was derived to predict the maximal sound pressure level of heavy duty vehicles during a pass-by in 7.5 m distance with the parameters vehicle speed and number of axles. With help of recently published information about external costs caused by heavy duty vehicles and the noise prediction tool, a model was developed to derive a money equivalent that can be used as a bonus/malus in a heavy duty vehicle fee. As a measure at the infrastructure, the installation of low-noise pavements is an effective, durable and economically attractive measure. Recent experiences with different technologies from all over the world are compiled and evaluated. On the rail side, an overview of the possible noise reduction strategies is given, followed by a discussion of the current policy and legislation in the EU and on the national level of different European countries.     

车用交流发电机噪声声学试验室设计

根据车用交流发电机噪声特性,介绍车用交流发电机噪声声学试验室半消声室指标选取依据和发电机驱动试验台的主体设计方案及验收思路。发电机噪声声学试验室的建立,为今后汽车发电机设计和噪声品质控制及优化提供了有效的验证手段,进一步加强了企业的自主研发能力,特别是解决发电机噪声问题的能力。     

结构-电磁激励下某电驱总成噪声控制

针对某电动汽车电驱总成的噪声问题，依据电驱总成车内噪声产生机理，进行整车状态声振特性测试，运用不同工况组合下的频谱特征和阶次特征等分析方法，识别出该电驱总成噪声问题为结构共振和电磁激励所致。针对结构共振问题，考虑电驱总成结构耦合特性、电机材料复杂多样性和线圈绕组质量，建立电驱总成有限元分析模型，求解出电驱总成的模态和振动响应，并通过敲击法模态试验得到模态参数进而对有限元模型进行验证，在此基础上以模态应变能为依据对电驱总成结构的局部刚度进行优化，提升结构共振频率，降低共振风险。针对电磁激励问题，以电驱总成中的永磁同步电机为研究对象，建立电磁仿真分析模型，以影响磁通密度的转子槽口的槽形、槽宽、槽深和槽间角度4个因素建立正交试验设计表，通过极差值得到各因素对齿槽转矩和输出转矩的影响水平，最后以降低齿槽转矩、加工工艺简单和对输出转矩影响小为目标，运用16组具有代表性的电磁方案，完成256个参数组合的寻优，并对优化方案进行了数值仿真计算。研究结果表明：优化方案的改善效果较显著；研究可为电动汽车车内噪声改善提供试验技术支持，并为电驱总成的结构共振噪声和电磁噪声控制提供方法参考。     

有自由液面的陷落式圆腔流噪声实验研究

采用基于经验模态分解(EMD)的本征模态函数(IMF)分析法和对比实验法研究了有自由液面的陷落式圆腔的流噪声,实验流速为0.4m/s~2.0m/s,间隔0.2m/s。实验发现当流速为0.4m/s~0.6m/s时,腔内液体有明显的振荡现象,其表现形式为液体沿腔内深度方向的大幅上下运动,称为“活塞(Piston)”现象。当流速大于等于0.8m/s时,腔内无振荡现象出现。通过对背景噪声和腔流噪声的本征模态函数作对比分析,得到了腔内流噪声的特性。     

干涉型声屏障结构的研究

干涉型声屏障基于声波干涉消声原理并依据铁路噪声源特点设计制造而成。声学模型试验测试结果表明,干涉装置的降噪作用主要体现在位于声影区和亮区之间的过渡区域(亦称灰色区域),干涉装置附加降噪效果为3.0～5.6dB,与同高度的直立形声屏障相比,降噪效果提高2.0～3.2dB。与其它顶部吸声体相比,干涉型声屏障更适宜于控制铁路噪声。因此,在铁路噪声控制工程中具有良好的应用前景。