基于SEA的空腔结构声学建模与吸声降噪优化研究

发布时间：2018-07-04 19:19

本文选题：空腔结构 + 统计能量分析法　；参考：《广西大学》2017年硕士论文

【摘要】：空腔结构作为汽车、列车等交通工具的舱室和人体的主要接触区域,其噪声的大小与人的乘坐舒适性密切相关,舱室的声学设计水平直接影响其腔内噪声大小。因此,研究空腔结构的声学建模、低噪声设计及优化方法,控制舱室内噪声,对于改善乘员的乘坐环境具有重要的理论和工程实际意义。本文基于统计能量分析法(Statistical energy Analysis,简称SEA)、正交优化理论及混料优化设计方法,在声腔结构的声学建模、降噪优化及吸声材料混料优化设计等方面进行研究与探讨,其主要工作与成果如下:针对声腔结构统计能量分析模型中的下限频率偏高的问题,提出声腔结构参数模态数灵敏度分析方法,推导空腔结构子系统模态数灵敏度数学模型,计算子系统的模态数对其厚度、面积、材料密度和空腔体积的一阶灵敏度。运用响应曲面设计法判断各因子对模态数的显著性,通过响应优化器求解目标响应条件下各因子的取值范围,建立能够初步满足中频噪声预测的空腔结构SEA模型。从而通过建模实现统计能量分析频率下限的拓展,为空腔结构中频噪声的预测提供一种新途径。建立空腔结构的声辐射功率模型和SEA仿真模型,通过设置多组仿真试验计算分析激励源位置、数量及特性对声腔结构振动与声学特性的影响,得到多源激励条件下的显著激励源,并通过单源或多源控制的方法实现声源降噪优化。运用正交优化的理论和方法,设计空腔结构吸声降噪的因素水平及正交优化表,并基于VA One软件所建模型对因素水平的不同组合进行仿真计算与优化,得到腔内评价点的总声压级及主要峰值频率的最优组合,为有效进行空腔结构噪声的控制提供依据。提出混料吸声设计的概念和类型,建立混料吸声的SEA模型,并通过仿真计算研究聚酯、泡沫塑料、铸造泡沫、聚氨酯、三聚氰胺五种泡沫吸声材料的吸声特性。针对均匀混料吸声材料,对比不同特性的吸声材料混料组合吸声性能的优越性,探讨以评价点声压级为控制目标和以吸声材料特性为目标的吸声材料混料优化设计方法,得到满足降噪要求的多种吸声材料混料最优配比。研究叠层混料吸声材料的田口设计方法,运用信噪比和均值分析判断不同控制因子在相应频段中的重要性,得到叠层混料吸声最优组合,为通过优化设计实现满足降噪需求的高性能吸声材料提供新的方法。应用BK3560C声学测试系统及阻抗管测试系统,开展叠层混料吸声材料吸声特性的试验研究,验证吸声材料叠层混料优化结果的正确性和有效性。
[Abstract]:As the main contact area between the cabin and human body of vehicles, trains and other vehicles, the noise level of the cavity structure is closely related to the comfort of human riding. The acoustic design level of the cabin directly affects the size of the chamber noise. Therefore, it is of great theoretical and practical significance to study the acoustic modeling, low noise design and optimization method of cavity structure, and to control the noise in the cabin. In this paper, based on Statistical energy Analysis (sea), orthogonal optimization theory and mixing optimization design method, the acoustic modeling, noise reduction optimization and sound absorption material mixing optimization design of acoustic cavity structure are studied and discussed. The main work and results are as follows: aiming at the problem of high lower limit frequency in the statistical energy analysis model of cavity structure, a sensitivity analysis method for modal number of cavity structure parameters is proposed, and a mathematical model of modal number sensitivity of cavity structure subsystem is derived. The first order sensitivity of the modal number of the subsystem to its thickness, area, material density and cavity volume is calculated. The response surface design method is used to determine the significance of each factor to the modal number, and the response optimizer is used to solve the range of each factor under the target response condition, and the sea model of the cavity structure which can satisfy the prediction of intermediate frequency noise is established. Thus, the expansion of the lower limit of frequency of statistical energy analysis is realized by modeling, which provides a new way for the prediction of intermediate frequency noise in cavity structure. The acoustic radiation power model and sea simulation model of cavity structure are established. The effects of the position, quantity and characteristics of excitation source on the vibration and acoustic characteristics of cavity structure are analyzed by setting up multi-group simulation experiments. Under the condition of multi-source excitation, the significant excitation source is obtained, and the noise reduction optimization of sound source is realized by single source or multi-source control method. Based on the theory and method of orthogonal optimization, the factor level and orthogonal optimization table of sound absorption and noise reduction in cavity structure are designed, and the simulation and optimization of different combinations of factors are carried out based on the model built by VA one software. The optimal combination of the total sound pressure level and the main peak frequency of the evaluation points in the cavity is obtained, which provides the basis for the effective control of the cavity structure noise. The concept and type of sound absorption design were put forward, the sea model of sound absorption was established, and the sound absorption characteristics of polyester, foam, casting foam, polyurethane and melamine foam were studied by simulation. Aiming at the sound absorption materials with uniform mixing, compared with the advantages of the sound absorption properties of the mixture with different characteristics, the optimum design method of the sound absorbing materials mixture with the control target of evaluating the sound pressure level at the point and the characteristics of the sound absorbing materials with the aim of evaluating the sound pressure level is discussed. The optimal ratio of various kinds of sound absorbent materials is obtained to meet the requirements of noise reduction. The design method of Taguchi for laminated mixing sound-absorbing materials is studied. The importance of different control factors in the corresponding frequency band is judged by using SNR and mean value analysis, and the optimal combination of sound absorption of laminated mixture is obtained. It provides a new method for achieving high performance sound absorption materials to meet the demand of noise reduction by optimizing design. By using BK3560C acoustics test system and impedance tube test system, the sound absorption characteristics of laminated mixing materials are studied, and the correctness and validity of the optimized results are verified.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB535

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