宽频带单层微穿孔板吸声体的研究

发布时间：2018-11-19 19:35

【摘要】：微穿孔板(Micro-perforated panel, MPP)吸声体由我国著名声学专家马大猷教授于1975年提出,并建立了相关理论模型,称为马氏理论模型。微穿孔板吸声体自提出以来,就以其坚固、质轻、耐蚀和环境友好等诸多优点,被广泛应用于建筑物、船舶、飞机、消声器等众多领域,被誉为21世纪可以替代传统多孔吸声材料的最具吸引力的新一代吸声材料。然而,传统单层微穿孔板吸声体的一个显著缺点是吸声带宽较窄,一般为1-2个倍频程,作为一个通用的吸声结构这是远远不够的。此外,由于安装空间的严格限制,许多噪声控制问题都要求薄的降噪结构。因此,如何在不增加吸声体厚度的情况下拓宽单层微穿孔板吸声体的吸声带宽是目前的一个研究热点。本文重点围绕如何拓宽单层微穿孔板吸声体的吸声带宽,开发薄降噪结构展开相关研究。主要的研究内容包括以下几个方面： 1.微穿孔板吸声体的吸声特性由其结构参数决定,如穿孔直径、板厚、穿孔率和空腔深度。本文通过MATLAB数值仿真对微穿孔板吸声体的吸声特性进行了参数化研究,得到了各结构参数与其吸声特性相互影响的规律。在充分理解微穿孔板吸声体吸声特性随其结构参数变化规律的基础上,设计了基于C++的面向微穿孔板吸声结构和吸声特性混合设计的软件平台,与以往微穿孔板吸声体设计平台不同,此平台综合考虑了结构参数和吸声特性参数两方面的限制,在实现微穿孔板吸声体按需设计的同时可兼顾最大吸声系数与吸收带宽之间的相互制约关系,提供满足混合设计要求的优化结构参数组合。 2.实验探讨了超微孔微穿孔板吸声体的吸声性能。马氏理论模型预测穿孔直径小于100um的超微孔微穿孔板吸声体可达到单层微穿孔板吸声体的吸声带宽极限,但限于传统加工工艺如机械钻孔、针刺等对超微孔的加工难度,超微孔微穿孔板吸声体一直鲜见报道。本文对超微孔微穿孔板的加工工艺进行了探索研究,应用微机电系统(Micro-electronic Mechanical Systems, MEMS)工艺制作了超微孔微穿孔板。任何加工工艺都存在加工误差,对于传统的大孔径微穿孔板吸声体,数微米的加工误差基本可以忽略,然而对于孔径小于100um的超微孔微穿孔板,加工误差的影响可能不可忽略。本文建立了计及加工误差的MPP理论分析模型,率先从理论上探讨了加工误差对超微孔微穿孔板吸声体吸声性能以及马氏理论模型关于超微孔微穿孔板吸声体适用性的影响,数值仿真结果表明一定范围内的加工误差不影响超微孔微穿孔板吸声体的吸声性能以及马氏理论对其吸声性能预测的准确性(最大预测误差仍在6%以内)。最后,在驻波管中使用驻波比法测量得到超微孔微穿孔板吸声体的垂直入射吸声系数,实验验证了马氏理论模型关于单层微穿孔板吸声体带宽极限的理论预测以及计及加工误差的MPP理论分析模型关于加工误差对超微孔微穿孔板吸声体吸声性能影响得出的结论。 3.理论与实验研究了多孔径微穿孔板吸声结构。基于MEMS工艺制作的超微孔微穿孔板吸声体可达到单层微穿孔板吸声体的带宽极限,且体积小,对有限吸声空间的降噪问题具有巨大吸引力,但随着孔径的减小,其吸声频带将移向高频,因而低频吸声性能变差,不利于中低频的降噪需求,且其制作成本相对于普通微穿孔板也较高。多孔径微穿孔板吸声结构具有优异的中低频吸声性能,其结构参数经过适当的设计可达到与多层MPP相当的吸声效果,且多孔径微穿孔板吸声结构更薄,适宜于狭小空间的降噪需求,不需要采用超微孔,制作成本较低。然而,多孔径微穿孔板吸声结构缺乏系统理论模型,因而无法对其吸声性能进行理论预测进而实现按需设计。本文基于体积流连续的原理,推导得到了声波垂直入射条件下多孔径微穿孔板吸声结构垂直入射吸声系数的理论计算公式,探讨了不同孔径微孔的排列及空腔中的隔板对多孔径微穿孔板吸声结构吸声性能的影响,最后通过实验验证了该理论模型的有效性,奠定了多孔径微穿孔板吸声结构的理论基础。 4.相对于传统单层微穿孔板吸声体,多孔径微穿孔板吸声结构引入了更多的可变结构参数,大大增加了其设计复杂性,限制了其在实际降噪问题中的应用。为克服这一问题,本文提出了应用多种群遗传算法对多孔径微穿孔板吸声结构进行优化设计,在加工工艺允许的条件范围内,寻找最佳的参数组合,使其在设定的频带范围内平均吸声系数最高,达到宽频带高吸收的效果。最后,对该算法的有效性进行了实验验证,结果表明多种群遗传算法可作为一种直接、快速、高效的优化工具实现多孔径微穿孔板吸声结构的优化设计。
[Abstract]:Micro-perforated panel (MPP) sound-absorbing body was proposed in 1975 by the famous acoustic expert of China, and the relevant theoretical model is set up, which is called the horse's theory model. The micro-perforated plate sound-absorbing body has been widely used in many fields such as buildings, ships, airplanes, silencers, It is known as the most attractive new generation of sound-absorbing material that can replace the traditional porous sound-absorbing material in the 21st century. one significant disadvantage of the conventional single-layer microperforated plate sound-absorbing body, however, is that the sound-absorbing bandwidth is narrow, typically from 1 to 2 octave, as a general sound-absorbing structure, Enough. In addition, due to the strict limitations of the installation space, many noise control problems require a thin noise reduction Therefore, how to broaden the sound absorption bandwidth of a single-layer micro-perforated plate sound-absorbing body without increasing the thickness of the sound-absorbing body is one of the present research This paper focuses on how to broaden the sound absorption bandwidth of a single-layer micro-perforated plate sound-absorbing body and to develop a thin and noise-reducing structure. Open the relevant research. Main research contents includes the following aspects: 1. the sound-absorbing properties of the micro-perforated plate sound-absorbing body are determined by its structural parameters, such as the diameter of the perforations, In this paper, the sound absorption characteristics of the sound-absorbing body of the micro-perforated plate are studied by the numerical simulation of MATLAB, and the parameters of the structure are obtained. Based on the understanding of the characteristics of the sound absorption of the micro-perforated plate and its structural parameters, a software platform based on the mixed design of the sound-absorbing structure and the sound-absorbing property of the micro-perforated plate based on C ++ is designed. The design platform of the hole-plate sound-absorbing body is different, and the platform comprehensively considers the limitation of both the structural parameters and the sound-absorbing characteristic parameters, and the mutual restriction relationship between the maximum sound absorption coefficient and the absorption bandwidth can be taken into account when the sound-absorbing body of the micro-perforated plate is designed according to the requirements, and the hybrid design is provided. a combination of the required structural parameters.................................................... The sound-absorbing performance of the micro-porous micro-perforated plate sound-absorbing body is predicted by the theory model of Ma's theory. The sound-absorbing body of the super-microporous micro-perforated plate with the perforation diameter of less than 100um can reach the limit of the sound absorption band of the single-layer micro-perforated plate sound-absorbing body, but is limited to the traditional processing technology such as mechanical drilling. The processing difficulty of the ultra-micro-pores, such as the holes, the needling, and the like, is extremely small, In this paper, the processing technology of the micro-porous micro-perforated plate is studied, and the micro-electro-mechanical systems (MEM) and the micro-electro-mechanical systems (MEM) are applied. The ultra-micro-porous micro-perforated plate is manufactured through the process of S). The machining error is present in any machining process. For the conventional large-aperture micro-perforated plate sound-absorbing body, the processing error of several micrometers can be ignored, however, for the super-micro-porous micro-perforated plate with the aperture of less than 100um, The influence of machining error may not be neglected. In this paper, the MPP theory analysis model of the meter and the machining error is established, and the sound absorption performance of the super-micro-porous micro-perforated plate sound-absorbing body and the model of the horse's theory are first discussed in this paper. The numerical simulation results show that the processing error in a certain range does not affect the sound absorption performance of the super-micro-perforated plate sound-absorbing body and the accuracy of the performance prediction of the sound-absorbing body of the micro-perforated plate. (The maximum prediction error is still within 6%). Finally, in the standing wave tube, the standing wave ratio method is used to measure the ultra-micro-porous micro-threading. The vertical incidence sound absorption coefficient of the sound-absorbing body of the hole plate is experimentally verified. The theoretical prediction of the bandwidth limit of the single-layer micro-perforated plate and the MPP theoretical analysis model of the meter and the processing error are verified by the experiment. the effect of the sound-absorbing properties of the sound-absorbing body. The sound-absorbing structure of the multi-aperture micro-perforated plate is studied and studied. The sound-absorbing body of the super-porous micro-perforated plate based on the MEMS technology can reach the bandwidth limit of the single-layer micro-perforated plate sound-absorbing body, and the volume is small, the noise-reducing problem of the limited sound-absorbing space is very attractive, With the reduction of the aperture, the sound absorption band will be shifted to the high frequency, so the low-frequency sound absorption performance is deteriorated, and the noise reduction requirement of the medium and low frequency is not favorable, and The sound-absorbing structure of the multi-aperture micro-perforated plate has excellent middle-low-frequency sound absorption performance, and the structure parameter of the multi-aperture micro-perforated plate has the sound absorption effect equivalent to that of the multi-layer MPP, and the sound-absorbing structure of the multi-aperture micro-perforated plate is thinner, and is suitable for the narrow-band micro-perforated plate. Small-space noise reduction required however, that sound-absorbing structure of the multi-aperture micro-perforated plate lacks the theoretical model of the system, so it is not possible to absorb it. In this paper, based on the principle of continuous flow of volume flow, the sound absorption of multi-aperture micro-perforated plate under the condition of vertical incidence of sound wave is derived. The theoretical calculation formula of the vertical incidence sound absorption coefficient of the structure is calculated, the influence of the arrangement of the micro-pores of different apertures and the sound absorption of the sound-absorbing structure of the multi-aperture micro-perforated plate in the cavity is discussed, and the effectiveness of the theoretical model is proved by the experiment. The theoretical basis of the sound-absorbing structure of the multi-aperture micro-perforated plate is given. In order to overcome this problem, a multi-group genetic algorithm is applied to optimize the sound-absorbing structure of multi-aperture micro-perforated plate. so that it is within the set frequency band range, The average sound absorption coefficient is the highest, and the effect of broadband high absorption is achieved. Finally, the effectiveness of the algorithm is verified, and the results show that the multiple group genetic algorithm can be used as a direct, fast and efficient optimization.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TB535

【共引文献】