阻抗管吸隔声测量系统的设计与实现

发布时间：2018-03-24 10:14

本文选题：声学材料　切入点：阻抗管　出处：《吉林大学》2017年硕士论文

【摘要】：材料的吸声系数和隔声量是两个具有重要意义的声学特性,在建筑学、汽车、工业领域有着广泛的应用与研究价值。目前,实验室中常用的测量材料的吸声系数和隔声量的方法主要有两种:混响室法和阻抗管法。混响室法测量虽然具有声波可以无规则入射,样品可为非均质材料的优点。但运用混响室法测量对测试房间有较高的要求,其造价成本高,不易实现。阻抗管法的优点在于能够测量声波垂直入射时的吸声系数、反射系数以及阻抗和导纳且测量样品小易获取,测量方法简单,适合推广普及。本文针对运用阻抗管法测量材料的吸声系数和隔声量展开工作。本文首先基于管中平面波理论,推导出在声波导管中形成平面波的条件。详细的介绍了运用阻抗管法测量材料吸声系数的驻波比法和传递函数法,测量材料隔声量的双负载测量法和四传感器法的理论基础以及公式推导,为后续的实验操作做好理论铺垫。本文的主要工作在于依据标准ISO 10534-1:1996和ISO10534-2:1998开发设计了测量材料吸声系数和隔声量的实时测量系统:阻抗管,其中包括:阻抗管材料的选择、长度的设计、扬声器筒的设计、传声器孔的设计和衔接方式的确定。同时介绍了实验中扬声器、传声器、数据采集卡、信号调理器的工作原理和性能参数,搭建一套完整的阻抗管测量系统。本文以传递函数法为测量原理,运用MATLAB软件编写了阻抗管法测量材料吸声系数和隔声量的算法。为验证此算法的正确性,运用virtual.lab软件进行模型仿真,建立与阻抗管等比例的阻抗管数值模型,将其仿真计算结果与理论结果对比,吸声和隔声均具有较好的一致性,说明算法的正确性。为进一步验证阻抗管的精准度,选用标准的试件聚氨酯和发泡橡胶进行吸声系数与隔声量的实验测量,得到的结果与北京声望公司的阻抗管测量系统所测量的结果基本一致,有效地说明了本测量系统的精准性。通过本文的理论研究和实验验证,充分证明了本系统的可行性和可靠性。运用此阻抗管测量系统对生活中常见的几种吸声和隔声样品进行测量,例如:鸡蛋棉、海绵、聚氨酯、木头、玻璃、高密泡沫板、铁等。对比样品在不同情况下测量时吸声系数的变化,分析得到:当吸声样品的背衬条件为空气柱时,随着空气柱变长,吸声频带向低频移动;玻璃棉样品的吸声系数随着频率的增大而增大;石膏穿孔板背衬为吸声样品时,其峰值吸声系数变大,频带变宽等。并整理实验数据,为材料的吸声性能和隔声性能提供参考。
[Abstract]:The sound absorption coefficient and sound insulation of materials are two important acoustical properties, which have wide application and research value in architecture, automobile and industry. There are two main methods to measure the sound absorption coefficient and sound insulation of materials in the laboratory: reverberation chamber method and impedance tube method. The sample can be a heterogenous material, but the reverberation chamber method has a high requirement for the test room, its cost is high, and it is difficult to realize. The advantage of the impedance tube method is that it can measure the sound absorption coefficient when the sound wave is incident perpendicularly. The reflection coefficient, impedance and admittance are easy to obtain and the measurement method is simple and suitable for popularization. In this paper, the acoustic absorption coefficient and sound insulation of materials measured by impedance tube method are studied. Firstly, based on the theory of plane wave in tube, The conditions for the formation of plane waves in acoustic conduits are derived. The standing wave ratio method and transfer function method for measuring the sound absorption coefficient of materials using impedance tube method are introduced in detail. The theoretical basis and formula derivation of dual-load measurement and four-sensor method for measuring sound insulation of materials. The main work of this paper is to develop and design a real-time measuring system for measuring the sound absorption coefficient and sound insulation of materials based on the standard ISO 10534-1: 1996 and ISO10534-2:1998. The design of the length, the design of the loudspeaker tube, the design of the microphone hole and the determination of the connection mode are also introduced. At the same time, the working principle and performance parameters of the loudspeaker, microphone, data acquisition card, signal regulator in the experiment are introduced. A complete measuring system of impedance tube is built. In this paper, based on the transfer function method and MATLAB software, an algorithm for measuring the sound absorption coefficient and sound insulation of materials is developed. The numerical model of the impedance tube with the same proportion as the impedance tube is established by using virtual.lab software. The simulation results are compared with the theoretical results. The results of sound absorption and sound insulation are in good agreement. In order to further verify the accuracy of the impedance tube, the sound absorption coefficient and sound insulation of the standard polyurethane and foamed rubber were measured experimentally. The results obtained are basically consistent with those measured by the impedance tube measurement system of Beijing prestigious Company, which effectively explains the accuracy of the measurement system. The feasibility and reliability of the system are fully proved. The impedance tube measurement system is used to measure several kinds of sound absorption and sound insulation samples, such as egg cotton, sponge, polyurethane, wood, glass, high density foam board, etc. Compared with the change of the sound absorption coefficient when the sample is measured under different conditions, the results show that: when the backing condition of the sound absorption sample is air column, with the air column becoming longer, the frequency band of sound absorption moves to low frequency; The sound absorption coefficient of glass cotton sample increases with the increase of frequency, and the peak sound absorption coefficient of gypsum perforated board is increased and the frequency band is widened when the backing of gypsum perforated plate is used as sound absorption sample. The experimental data are arranged in order to provide reference for the sound absorption and sound insulation properties of the material.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB52

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