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水下噪声及其控制技术进展和展望   总被引:10,自引:0,他引:10       下载免费PDF全文
何祚镛 《应用声学》2002,21(1):26-34
本文主要介绍近年来船舶行业水下噪声研究进展情况,包括水下噪声形成机理和预报;水下噪声控制技术;水下噪声近代测量分析技术,并提出对水下噪声研究工作的展望。  相似文献
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Definition of road roughness parameters for tire vibration noise control   总被引:2,自引:0,他引:2  
Road roughness plays an important role in the generation of tire vibration noise. However, it is unclear which kinds of road roughness parameters should be controlled to reduce the noise. In this paper, we define the essential road roughness parameters that govern tire tread vibration and provide information on tire/road noise abatement. The detailed effects of road roughness parameters on tire tread vibration are estimated using a tire/road contact model. The results reveal that pavement asperity height itself is not an essential parameter, but asperity height unevenness, asperity radius, and asperity spacing are important for the abatement of tire vibration noise.  相似文献
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目的:探索随机振动和正弦振动因素下生成语音在听觉效果上的变化规律。方法:随机振动采用频率范围2-20Hz,加速度为0.3G、0.5G、0.7G(有效值,下同),正弦振动采用频率4、6、8、10、12Hz,加速度为0.3G、0.5G;在安静及信噪比分别为0dB和-6dB三种状态下对随机振动组、正弦振组及对照组3个组的语音材料进行清晰度测试。结果:和对照组相比,随机振动组,清晰度几科没有变化,正弦振动组,0.3G时4Hz、0.5G时6Hz和8Hz作用下语音清晰度有明显降低,检验结果非常显著。研究还发现,清晰度的降低随听音环境的信噪比的降低而变得严重;结论:正弦振动对发音人发音的影响,会使通话效果变差,并且在听音环境恶劣时尤为突出。  相似文献
4.
贾甲  冯音琦 《应用光学》2009,30(4):610-615
改进和完善宽场光学相干断层成像技术(WFOCT)的主要方法是从光源、系统光路等方面进行改进.研究WFOCT系统的成像状态和环境状态对系统的横向分辨率的影响,借助ZEMAX光学设计软件模拟该系统的干涉效果,在实验中采用八步移相法来解析样品的二维图像信息,将解析出来的样品图像赋值到图像变量中进行存储显示.实验与模拟结果表明:模拟仿真获得的干涉信号含有对比度和平行度很高的干涉条纹,证明了利用ZEMAX软件模拟仿真干涉系统的可行性.  相似文献
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Rock blasting may cause disturbances, fear, and annoyance in residential and community areas affected by such activities. These community reactions can be quite strong, even when the blasting activities and the resulting vibrations are unlikely to cause physical damage to building foundations or buildings. A socio-vibrational survey was undertaken to assess residential reactions to blasting activities. Vibration velocities were obtained for 520 respondent dwellings located in seven study areas, and compared to the residents’ assessments of environment quality. Even at low vibration values, many people report annoyance. Exposure–effect relationships with acceptable statistical error bands were obtained. The level of annoyance from long-term blasting activities (quarry blasting) was not higher than from finite periods of more intense blasting activities (road and rail tunnels). Providing information in advance of the blasting activities, can reduce community reactions. Self-reported sensitivity to vibrations was associated with significantly increased annoyance. Sensitivity to vibrations was uncorrelated with exposure to vibrations. Sensitivity to noise and sensitivity to vibration were moderately correlated.  相似文献
6.
在研究微球腔和锥形光纤耦合的基础上,介绍了耦合系统中外界空气流动等带来的振动噪声对耦合距离的影响,并系统地分析了耦合距离与系统耦合状态的关系。为进一步验证外界各种振动噪声对系统稳定性的影响并解决这些因素对谐振谱线造成的干扰,采取了两种方法来进行抑制:一种是设计了隔离罩将耦合系统与外界环境隔离,另一种是用紫外胶将锥形光纤与微球腔封装在一起。实验结果显示,这两种方法均可使系统达到相对稳定的状态,论证了两种方案的可行性。在第二种方案中,黏合为一体的微球腔结构彻底与外界隔离,不会再受振动噪声的干扰,为后续的实验奠定了良好的基础。  相似文献
7.
为了对油底壳的改进方案进行噪声预测,首先建立油底壳的流固耦合有限元模型,进行耦合模态计算,获得其固有频率和振型,通过模态试验验证了耦合有限元模型的准确性;其次,在发动机工作过程中,通过试验测得油底壳各螺栓固定处的振动加速度;再次,基于模态结果,在油底壳各螺栓固定处施加测试的振动加速度,采用有限元的分析方法对油底壳进行了强迫振动计算和辐射噪声计算,并进行了试验对比,结果表明该方法可用于发动机开发试验确认阶段,对油底壳改进方案进行振动噪声的预测,减小开发风险;最后,对含油量多少对辐射噪声的影响进行了对比分析。  相似文献
8.
低频水声探测和船舶减振降噪技术发展,使得传统水声目标识别技术性能逐渐下降。该文分析了声呐工作带宽、探测频率、船舶减振降噪给识别技术带来的挑战。针对低频声呐广泛使用的低频线谱识别,研究了低频线谱的识别能力问题;针对智能识别技术发展,研究了深度学习技术在船舶辐射噪声识别中的应用问题,并给出了数据试验结果,文章最后指出了水声被动目标识别技术亟需开展的研究内容和方向。  相似文献
9.
Producing a broad locally-resonant bandgap for low frequencies in a phononic crystals is a challenging task, using conventional methods. In this paper, we describe the design of a broad, locally-resonant, bandgap in a phononic crystals using a numerical simulation. The structure consists of periodic double-sided novel composite sonators, deposited on a 2D locally-resonant phononic-crystals plate made of a rubber-filler array, which is embedded in an epoxy plate. Using the finite element method, we calculate the dispersion relations, the power-transmission spectra, and the displacement fields for the eigenmodes. Our results confirm that, the new structure facilitates a significant increase in absolute bandwidth (by a factor of 4.2) compared to conventional phononic crystals. It also broadens the range of elastic wave attenuation. The formation mechanisms that generates the broad locally-resonant bandgap is explored numerically. The simulation indicates that the formation of this bandgap is possible due to coupling between the entire vibration mode of the novel composite-resonator and the Lamb-wave mode of the 2D locally-resonant phononic-crystals plate. The bandwidth of the locally-resonant bandgap is determined by the resonator mode. This study opens new possibilities to broaden locally-resonant bandgaps of phononic crystals for low frequencies. The results can potentially be used to reduce vibration and noise in many applications.  相似文献
10.
唐昭  张学飞  王瑞乾 《应用声学》2020,39(5):709-715
为探究一种复式降噪块装置及其组合形式对某S型辐板地铁车轮的减振降噪效果和机理,在半消声室内,分别对1种自由状态下的标准车轮和3种形式的复式降噪块车轮开展振动声辐射特性及阻尼特性试验,并通过有限元建模对其进行了模态计算。结果表明:复式降噪块装置可在全频段内提高车轮阻尼比,并对车轮各部位有良好的减振效果,以轮辋和踏面的减振效果最为显著;其中,6个制振阻尼片形式的降噪块对车轮的降噪效果最显著,径向激励下的降噪量为13.1dB(A),轴向激励下的降噪量为11.1dB(A),降噪频段主要集中在1000Hz以上中高频。该文研究结果是对列车降噪研究领域的补充和发展。  相似文献
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