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基于免疫算法的音乐厅形体优化
The Shape Optimization of Music Halls Based on Immune Algorithms
【作者】 李运江;
【作者基本信息】 华南理工大学 , 建筑技术科学, 2014, 博士
【摘要】 长期以来,各国声学家、音乐家和建筑师们对一些著名传统音乐厅为何能获得优良音质的原由、音乐厅几何形体的变化与声学主客观参数之间的相关关系以及如何在音乐厅形体设计上突破传统“鞋盒”式形体等方面进行了探索,并做了大量的理论分析及科学试验,取得了一些标志性成果。本文首先回顾了音乐厅的起源和形体发展的历史,简要介绍了前人对影响声场主观因子的维度和正交因子等方面所做的研究,综述了现代建筑声学研究的现状和取得的进展,以及基于这些理论而开展的音乐厅形体设计实践上的一些尝试,最后阐述了本课题的主要研究内容。文章简要介绍了免疫算法的发展沿革、机理、特性以及常见的算法类型,并用Matlab语言编制了免疫算法程序,解决了一个墙体隔声的优化问题,并求解出进化代数和种群分布特征,作为检验程序是否正确的例证。在采用虚声源法的基础上提出了一种简便的算法,能够执行对下级虚声源的快速判断。利用Matlab语言编程,实现了室内声场分布的可视化仿真,并能得到指定观众席接收点的声能脉冲响应。依据安藤四一提出的影响室内音质的四个相互独立的物理因子理论,用本课题编制的室内声学仿真软件可计算室内任意坐席的四个声学参量;并根据主观优选标度值理论,得到了音乐厅指定坐席的声学参量主观优选标度值以及总的主观优选标度值,并分别绘制出了它们的等值线图,所得结果与已有文献的结论相吻合。本文按照一定的规则将一个“鞋盒”式音乐厅几何形体进行编码,然后运用免疫算法程序加以优选,最后解码得到经过优化的音乐厅体形。研究表明,优化后音乐厅形体为一对称的不规则形状,其平面及剖面均呈锯齿状几何形体。就平面图来说,演奏乐台墙面中心向观众席凸起,观众席后墙中心向外凸;音乐厅两侧墙体各个矩形面转动朝向乐台,音乐厅两面端墙呈凹面状朝向观众席。就剖面图来说,音乐厅前部顶棚倾斜朝向观众席区域,后部顶棚以较大倾斜角度朝向观众席区域。与此同时,本文亦将一个“扇形”音乐厅作为优化算例,并将混响时间优选标度值加入到优化目标函数中,得到了相应的优化形体。本论文利用免疫算法实现对音乐厅体形优化的工作及其结论对于观演建筑体形设计具有一定的指导意义。
【Abstract】 For a long time, worldwide acousticians, musicians and architects have been paying theirattention to some acoustic issues, such as the reason why acoustics of some traditional musichalls could have been highly evaluated, the correlativity between geometric shape of musichalls and acoustical parameters of objectivity and subjectivity, and how to breakthroughtraditional Shoe-Box-Shape in music halls design. Lots of theoretical analysis and scientificexperiments have been done; some achievements have been made as well.This thesis has reviewed the history of origin and shape evolution of music halls,summarized the studies that have been done on the factors of orthogonal and subjectivedimensionality, briefly introduced current situation and progresses that have been achieved,some design innovations on shapes of music halls based on these theories are also presented.This thesis has introduced the evolution, mechanism, characteristics and styles ofimmune algorithm; the optimization program of sound insulation of walls has been realized inMatlab that is on the basis of comentropy immune algorithm, evolutionary process andpopulation distribution have been also simulated out in this dissertation. It is used to verify thevalidity of the optimization program.A concise algorithm has been suggested based on Image-Source Method that canimplement the quick judgment to the position of next image. Visualization simulation of roomsound field has been realized by a program in Matlab, Impulse Response of specifiedreceivers in rooms can be also obtained.According to the theory of four orthogonal physical factors that influence room acousticsthat has been proposed by Yoichi Ando, the program in Matlab developed by this paper cancalculate these four orthogonal physical factors at any receivers in the room. Also, the ScaleValues (SV) of subjective preferences at any specified receivers are calculated and the isolinesof these parameters are rendered respectively, the total SV of subjective preferences of threeacoustic parameters is also obtained, these calculated results are well consistent with theconclusions of existing literatures.Based on a certain rule, this paper has coded the geometric shape of a shoe-box musichall and applied them into an immune algorithm program, the final optimized shape of themusic hall are obtained after decoding optimal solution acquired by the program. The resultsshow that the optimized shape of the music hall is symmetric and irregular; the form is hacklyin the plane and section plane, center of endwall near the stage heaves to audience area andrear endwall is convex towards outside. Each rectangular surface of sidewalls rotates and faces towards to the stage. The front part of ceiling tilts to audience area and rear part turns toaudience area at a bigger inclination angle.Meanwhile, having added scale value of RT on optimization object function, this papertakes a fan-shaped music hall as an optimization example, and the optimized shape has beenobtained.Results of the research on shape optimization are significant for shape design ofperformance–oriented buildings.
【Key words】 music halls; sound-field simulation; preference scale value; immune algorithms; shape optimization;