共查询到19条相似文献,搜索用时 203 毫秒
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分析了飞机的喷流噪声产生机理,讨论了喷流噪声的控制技术.并将穿孔板共振吸声结构降噪技术应用到飞机的推进系统中,用以降低喷流噪声,并对其实际降噪效果进行了比较分析. 相似文献
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微穿孔板的主动吸声研究 总被引:1,自引:0,他引:1
提出用微穿孔板进行主动吸声的方法。用微穿孔板作为主动吸声的材料,检测出入射声波的频率,得到微穿孔板的共振频率,从而得到微穿孔板背后空腔的深度,移动微穿孔板背后的刚性壁以满足空腔深度的要求,使得吸声系数达到最大,从而达到主动吸声的目的。最后,进行了数值计算与实验,计算结果与实验结果能很较好的吻合,说明了该主动吸声方法的可行性。 相似文献
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在标准进气风管测试装置上,对某离心风机及在风机蜗壳周向板、前盖板、后盖板等部位分别加装吸声材料后,测试了不同结构形式下风机性能和噪声特性。试验结果表明:相比原风机,蜗壳周向板与后盖板同时加装吸声材料效果最好,设计工况下A声级能够降低7.2dB(A),在小流量工况下,吸声蜗壳的降噪效果变差;根据风机噪声频谱,穿孔板加玻璃棉吸声蜗壳的吸声性能中高频好于低频,风机基频噪声在设计点能够降低12.5dB(A);加装吸声材料后风机气动性能会略有下降,压力和效率都有不同程度的降低。 相似文献
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雷达设备风冷插箱散热设计是雷达产品可靠性结构设计、热设计的重要内容。在实际应用中,强迫风冷被广泛使用,散热和噪声控制往往产生矛盾。如何控制噪声,对改善产品使用环境有着重要意义。文中针对风冷插箱噪声过大问题,运用微穿孔板近似吸声原理,设计了一种消声插件,对该微穿孔板消声器的降噪效果进行了测试,可以减低噪声3 dB(A)左右。从而说明该消声器有一定的降噪效果,在一定场合可以应用。 相似文献
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Min-Chie Chiu Ying-Chun Chang Long-Jyi Yeh Gaung-Jer Lai 《The International Journal of Advanced Manufacturing Technology》2007,32(5-6):537-546
As investigated by the Occupational Safety and Health Act (OSHA) in 1970, noise is highly responsible for the psychological
and physiological illnesses of workers. Therefore, noise control for an enclosed manufacturing system using sound absorbers
becomes indispensable. Considering the minimal acoustic wool used in the high-performance sound absorber during design optimization,
the ratio of the sound absorption coefficient to the thickness of acoustic wool, a cost- and performance-oriented design index,
is then applied and served as a researched objective accordingly; what’s more, the thickness of the absorber is fixed in advance
for the sake of maintenance and access. In this paper, not only is the graphic analysis studied, but also, the computer-aided
numerical assessments are presented. In the computer-graphic analysis on sensitivity, one set of design data is developed
first. Additionally, the successive algorithm of iteration techniques and the original design data are carried out independently.
Moreover, the results are then confirmed by the Kuhn-Tucker condition for accuracy purposes. It is shown that the theoretical
and simulated results are in good agreement. The economical design of the sound absorber proposed in this study definitely
provides a quick and optimal approach to minimize the amount of acoustic wool used and retain the higher acoustic performance
of perforated single-layer absorbers under space restrictions. 相似文献
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In this paper, the sound absorptions of flexible curved micro-perforated panels that are backed by an air cavity are studied in detail. A theoretical model that is based on the classical plate equation coupled with an acoustic wave equation is developed for the prediction of sound absorption. This model considers both symmetrical and antisymmetrical structural acoustic responses. Using the electro-acoustic analogy approach, another model is developed that only considers single structural and acoustic modes. It is proposed to make use of panel and cavity resonances to widen the absorption bandwidth of a single/double perforated absorber. The absorption of a flexible micro-perforated panel can be further enhanced by adjusting its curvature to bring the resonant frequencies closer together. The effects of various parameters such as boundary condition, incidence angle, and curvature on the absorption are studied. Predicted results for the single and double layer absorbers show good agreement with measurements. 相似文献
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空调系统噪声是高速列车静置噪声的主要噪声源之一,改善风道传声特性是其减振降噪的关键所在。针对某高速列车阻抗复合消声风道结构,采用FE-SEA混合法,建立了风道传声特性分析模型,计算了100~3 150 Hz频率区段的风道传声特性,同时,基于声学有限元法计算了风道结构的声学模态,并据此分析了风道传声损失峰值和谷值的成因。为提高风道传声损失,分别从声学阻性和抗性优化两方面着手,对风道进行优化,包括选材、吸声包数量和位置等优化设计。计算结果表明:吸声选材优化可显著提高其传声损失,最大可达11.3 dB;吸声包数量和位置优化可提高其传声损失4.8 dB;阻抗复合优化方案最高可提高风道传声损失15.6 dB。相关结论可为高速列车空调系统减振降噪提供参考。 相似文献
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为了精确识别轴向柱塞泵壳体降噪区域,首先,搭建液压-多体动力学耦合模型,求解结构噪声激振力;然后,分析零部件模态并试验验证,建立装配体有限元模型,开展基于模态的振动响应分析,通过振动实验验证模型准确性,搭建轴向柱塞泵声学边界元模型,分析其辐射噪声特性;最后,基于声学传递向量原理,开展模态及板面声学贡献量分析,对壳体噪声辐射板面进行合理划分,分析其对关键频率下辐射噪声的贡献量。研究表明:轴向柱塞泵振声模型具有良好的准确性;某板面在辐射噪声突出的1350 Hz频率下,其声学贡献量达到46.1%。精确识别了轴向柱塞泵壳体降噪区域,为其降噪优化设计提供有效指导。 相似文献
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针对某型齿轮箱,提出一种基于声学贡献度分析的减振降噪设计方法.建立了齿轮箱有限元模型,计算其结构模态.将齿轮箱有限元网格作为结构网格和声学边界网格,在LMS Virtual.Lab下用边界元法求解真实工况激励下的辐射声场.利用声学贡献度分析,找到贡献度最大的面板,修改其设计参数.修改结构后,声场中某点噪声峰值降低8.2... 相似文献
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分别建立某装载机驾驶室及室内声腔有限元模型,通过单点输入多点输出(single input and multiple output,简称SIMO)法模态试验验证了声振耦合模型的准确性,测取悬置点激励进行频率响应分析及室内噪声预测。对驾驶室进行声学灵敏度分析,采用声传递向量法对驾驶室进行声学板件贡献度分析并对关键板件进行形貌优化,同时添加橡胶阻尼材料抑制壁板振动,进行二次声压虚拟预测。结果表明,声学灵敏度分析可得到多阶关键声振耦合频率,声传递向量法板件贡献度分析能准确定位产生噪声峰值的关键板件,形貌优化及添加阻尼材料的方案降噪效果显著,室内总声压级降低了4.43dB。此方案系统地为低噪声车身设计提供了技术路线,减少了传统方案的主观性和重复性,缩短了研发周期,降低了研发成本。 相似文献
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针对某轿车后悬架减振器出现的异响问题,进行阻尼器高频振动试验,对位移-阻尼力图形分析确定异响由复原阀系造成,通过对复原阀系进行结构设计优化,改善位移-阻尼力图形,最后将改善后的复原阀系装配于新的减振器进行噪声台架测试验证和整车道路试验验证,结果表明,改进后的减振器异响消除。 相似文献