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Noise cancellation using piezoelectric actuators as control sources.

机译：使用压电致动器作为控制源消除噪音。

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摘要

Loudspeakers are usually used for generating secondary noise in the active control of the sound in ducts. However, they are bulky, heavy, non-durable and of poor response at low frequencies. Piezoelectric actuators are suggested as an alternative control input in order to overcome some of the captioned disadvantages of the loudspeaker. Piezoelectric sources can reduce the level of acoustic potential energy in the enclosure by altering the vibration of the structure.; The objectives of the research in this thesis are to, (1) study the vibration modes of long thin plate excited by the piezoelectric actuators using the nonlinear analysis method; (2) investigate the coupling behaviour of the panel vibration and the sound field in a duct; (3) experimentally study the attenuation of unwanted sound at the low frequency in the duct by using the panel vibration control source excited by piezoelectric actuators.; A structural-acoustic coupled system of a long thin plate and a sound field in a duct is discussed. Piezoelectric actuators were used as a secondary (control) source to generate control disturbance to cancel the unwanted sound in the duct.; The plate excited by the piezoelectric actuators was analysed by the geometric nonlinear finite element method. A computer program for nonlinear vibration analysis is verified by comparing the theoretical results with the experimental results. The dynamic response of the plate vibration subjected to piezoelectric actuators is small because of the stiffness of membrane structure and the small control forces produced by the piezoelectric actuators.; Based on the experimental investigation, the vibration of a long thin plate can be used as the sound absorber at medium frequencies (170∼320 Hz). And the plate vibration excited by piezoelectric actuators can be used as the control source to cancel the unwanted sound at low frequencies (60∼140 Hz). The piezoelectric sources show the potential for noise cancellation in an enclosed sound field because of its advantages over the loudspeakers. Moreover, the piezoelectric source in this thesis can generate much higher sound pressure levels than the diaphragm piezoelectric actuation device.; This thesis introduces a new method for noise cancellation by using plate vibration excited by piezoelectric actuators as an acoustic control source to increase sound absorption instead of the conventional method of reducing sound transmission. It is also found that nonlinear vibration can degrade the performance of piezoelectric actuators as acoustic source but can improve the passive dissipation of noise.
机译：扬声器通常用于在主动控制管道中的声音时产生二次噪声。但是，它们体积大，笨重，不耐用并且在低频下响应性差。建议使用压电致动器作为替代控制输入，以克服扬声器的某些上述缺点。压电源可以通过改变结构的振动来降低外壳中的声势能水平。本文的研究目的是：（1）利用非线性分析方法研究压电致动器激励的长薄板的振动模式; （2）研究面板振动与管道中声场的耦合行为; （3）使用压电致动器激励的面板振动控制源，通过实验研究管道中低频处有害声音的衰减;讨论了长薄板与管道中声场的结构声耦合系统。压电执行器用作辅助（控制）源，以产生控制干扰，以消除管道中的有害声音。用几何非线性有限元方法分析了压电致动器激励的板。通过将理论结果与实验结果进行比较，验证了用于非线性振动分析的计算机程序。由于膜片结构的刚度和压电致动器产生的较小的控制力，承受压电致动器的板振动的动态响应较小。根据实验研究，在中频（170〜320 Hz）下，可以使用一块长薄板的振动作为吸声器。压电致动器激发的板振动可以用作控制源，以消除低频（60〜140 Hz）下的有害声音。压电源由于具有优于扬声器的优势，因此在封闭的声场中具有消除噪声的潜力。而且，本文中的压电源可以产生比隔膜压电致动装置高得多的声压级。本文介绍了一种通过使用压电致动器激励的平板振动作为声学控制源来增加声音吸收的新的消除噪声的方法，而不是传统的减少声音传播的方法。还发现非线性振动会降低压电致动器作为声源的性能，但会改善噪声的被动消散。

著录项

  • 作者

    Chong, Fan.;

  • 作者单位

    Hong Kong Polytechnic (People's Republic of China).;

  • 授予单位 Hong Kong Polytechnic (People's Republic of China).;
  • 学科 Engineering Civil.
  • 学位 Ph.D.
  • 年度 2000
  • 页码 291 p.
  • 总页数 291
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 建筑科学;
  • 关键词

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