乘用车车身结构噪声测量分析及控制

乘用车的车内低频噪声直接影响其乘座舒适性。本文探讨了声响感度分析、矢量合成分析，结构车内噪声声场耦合模态分析方法在车身结构噪声分析控制中的运用，在实车上其降噪效果也是令人满意的。     

声全息方法识别汽车运动噪声

本文提出利用声全息原理，对运动状态下的汽车噪声源进行识别的方法，它能够用来分析汽车在高速运动过程中发动机的噪声，轮胎噪声和空气动力学噪声，通过低速和高速实验表明该方法是一种有效的方法，能够快速，准确识别运动车辆的噪声。     

斜盘式压缩机运动学与动力学计算及工作噪声分析

斜盘式压缩机结构紧凑，正面投影面积小，便于在发动机上布置和调整；通过对其运动学和动力学分析，可以证明其可实现运动的完全平衡，从而带来振动小、噪声低的优点。但斜盘式压缩机活塞与斜盘之间的钢容易磨损，活塞换向时易出现“嗒嗒”声，随着间隙的增大，噪声也越加明显。经试验验证和数据分析，发现此现象与气缸孔和主轴孔的不平行度有很大关系，把该不平行度控制在０．０２ｍｍ以内，可收到良好的效果。     

汽车噪声的模拟及其应用

介绍了采用“分频带数字滤波法”来模拟汽车噪声的原理及其主要参数的选择，并通过试验证了该模拟方法和模拟系统的可行性，由此建立的汽车噪声模拟系统可用于研究汽车噪声对人体的各种生理指标和化指标的影响规律。     

发动机排气噪声有源控制技术的研究与应用

本文根据发动机排气噪声的声学特性提出了有源消声系统的数学模型。据此,对研制的控制系统进行的试验结果表明:在中低频段降噪效果明显,主要声峰频率上平均降噪量达13.6dB。     

Conformity: How VMT-speed distributions can affect mobile emission inventories

Transportation conformity is a US regulatory process that requires that transportation modeling be integrated with air quality modeling. Consequently, every change to either modeling process is undertaken with great scrutiny by the regional governments, who have to use the models for demonstrating conformity. This paper explores the "trip versus link debate," which stems from the fact that the standard travel demand models used by most metropolitan planning organizations are primarily link oriented, while the air quality models have been primarily trip oriented. Using the Sacramento region we examine the effects on mobile source emissions inventories when speed-VMT distributions are constructed using the trip and link-based philosophies. The results of our study indicate that trip-based VMT-speed distributions produce consistently lower emissions estimates than the link-based distributions. We use the results to assert that deciding between a trip-based or link-based conformity modeling process involves more than the technical difficulty of changesto the models or the potential political ramifications, it involves assessing which method will provide the most accurate estimates of regional motor vehicle emissions. We also examine ways to think about constructing mobile source emission inventories.     

隔振降噪技术的实船应用

某型测量船主辅机采用的单层局部隔振、浮筏双层隔振及约束阻尼处理等隔振降噪技术,基内就其设计论证、实船应用和检测结果作一简介。     

The effects of information bias and riding frequency on noise annoyance to a new railway extension in Hong Kong

We investigate how two non-acoustic factors, information bias and riding frequency, can affect the annoyance response of an urban population to noise created by a new railway line. The study shows that information bias is asymmetrical. Respondents receiving only information on positive measures taken by the authority to reduce noise emission are more tolerant of the noise impact, but those receiving only critical views tend to be more annoyed because they feel that not all measures to reduce noise have been employed. Additionally people who use the line frequently are more tolerant to the noise impact than those who do not. Information bias seems to have a temporary masking effect over riding frequency lasting for a few weeks after railway opening. This suggest that whilst free flow of information provided by the authority can help alleviate annoyance response, encouraging the people affected to make use of the new infrastructure may be useful to reduce public resistance and noise annoyance.     

土-结构相互作用的桥梁多尺度建模与分析

考虑土-结构相互作用(SSI)是地震激励下桥梁抗震性能评估的热难点之一.由于考虑土体影响多而建立的结构模型计算耗时极长,为了提高效率,现采用一致多尺度建模方法,将所研究部位建为实体单元,其他部位建为梁单元,单元之间采用适当的方法进行界面连接,保证宏观、精细单元间的变形协调,并对某一桥梁进行分析,验证了该方法的正确性.在此基础上,基于多尺度建模方法,建立三跨连续梁桥模型,对其进行弹塑性时程分析,对比分析考虑SSI和不考虑SSI效应的桥梁模型在地震激励下的响应结果,研究SSI效应对桥梁抗震性能的影响.结果表明:多尺度建模方法可以在保证计算精度的前提下有效地提高计算效率;考虑SSI效应能够有效地降低桥梁的抗震性能需求.因此,在设计时应加以考虑.