可调频声衬及其控制技术研究

发布时间：2019-03-08 11:56

【摘要】：声衬作为一种噪声控制的有效手段,具有安装方便、价格低廉、高频吸声系数高等显著优点,广泛地应用在飞机引擎、车辆动力舱以及建筑设计和工业设备等领域中。但传统声衬的消声频率受材料本身特性、结构制约,消声范围较窄,且当噪声源发生改变时,消声频率无法进行调节,因而研究具有调频功能的新型声衬,具有重要的理论意义与工程实用价值。本文在分析现有声衬的工作原理、声学性能的基础上,针对其无法调频的弊端,提出了一种了新型的可调频压电声衬。首先,基于逆压电效应设计了具有颈部调节、腔体体积调节的亥姆霍兹共振器结构。仿真和实验结果表明,腔体体积可调结构具有频率偏移范围大,线性性良好等特点。在对腔体体积可调结构进行优化的基础上,提出了一种双级腔体声衬,理论上分析了影响其共振频率偏移的因素。之后对多种类型压电片的进行分析测试优化,实验采用的经过参数改进后的50mm压电片,在400V电压下的位移量为0.5mm。其次,采用LabVIEW软件分别以传递损失和噪声频率作为判据编写了声衬系统的数据采集、分析和控制程序,并设计了与之对应的基于光敏电阻的驱动电压控制电路。测试结果表明,当采集卡输出电压为2.1V至4.0V时,驱动电路输出电压为0V至400V,实现了声衬驱动电压的自动调节。最后,构建了声衬系统的测试装置。分别加工并测试了35mm普通腔体和50mm双级腔体压电声衬的消声效果,结果表明50mm双级腔体压电声衬具有更大的消声频带偏移量,在0V-200V的电压范围内,其消声频带可以实现约200Hz的偏移。此外还设计了自适应声衬控制系统,以35mm压电声衬为例,其可调频范围为750Hz至782Hz,降噪量可以达到5dB。研究表明所设计的可调频压电声衬的自适应控制系统,可以使可调频压电声衬的消声频带随着噪声频率的变化而偏移,即拓宽了声衬的消声频率范围。
[Abstract]:As an effective means of noise control, acoustic lining has the advantages of convenient installation, low cost and high frequency sound absorption coefficient. It is widely used in the fields of aircraft engine, vehicle power cabin, architectural design and industrial equipment. However, the silencing frequency of the traditional acoustic lining is restricted by the characteristics and structure of the material itself, and the range of the silencing is narrow, and when the noise source is changed, the anechoic frequency cannot be adjusted, so the new type of acoustic lining with the function of frequency modulation is studied. It has important theoretical significance and practical engineering value. In this paper, based on the analysis of the working principle and acoustic performance of the existing acoustic lining, a new type of adjustable frequency piezoelectric acoustic lining is proposed, aiming at the disadvantage that it can not be modulated. Firstly, a Helmholtz resonator with neck adjustment and cavity volume adjustment is designed based on the inverse piezoelectric effect. The simulation and experimental results show that the cavity volume adjustable structure has the characteristics of large frequency offset range and good linearity. On the basis of optimizing the cavity volume adjustable structure, a kind of two-stage cavity acoustic lining is proposed, and the factors affecting the resonance frequency offset are analyzed theoretically. After that, many kinds of piezoelectric wafers are analyzed, tested and optimized. The displacement of the 50mm piezoelectric wafers with improved parameters is 0.5mm at 400V voltage. Secondly, the data acquisition, analysis and control program of the sound lining system are compiled by using LabVIEW software based on transmission loss and noise frequency respectively, and the corresponding driving voltage control circuit based on Guang Min resistance is designed. The test results show that when the output voltage of the acquisition card is from 2.1 V to 4.0 V, the output voltage of the driving circuit is from 0 V to 400 V, which realizes the automatic adjustment of the driving voltage of the sound lining. Finally, the testing device of the sound lining system is constructed. The anechoic effect of the piezoelectric liner of 35mm and 50mm double-stage cavity is processed and tested respectively. The results show that the piezoelectric liner of 50mm double-stage cavity has a larger frequency band offset, which is within the voltage range of 0V-200V. The anechoic frequency band can realize the offset of about 200Hz. In addition, an adaptive acoustic lining control system is designed. Taking the 35mm piezoelectric acoustic lining as an example, the range of frequency modulation is from 750Hz to 782Hz, and the noise reduction can reach 5dB. The research shows that the adaptive control system of the adjustable frequency piezoelectric lining can make the noise frequency band of the adjustable frequency piezoelectric lining shift with the change of the noise frequency, that is to say, the range of the noise attenuation frequency of the adjustable frequency piezoelectric lining can be broadened.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB535

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