【作者】 王巍；

【导师】 王晓明； 朱祥龙；

【作者基本信息】 大连理工大学 ， 机械工程（专业学位）， 2020， 硕士

【摘要】 随着军事工业、航空航天、城市轨道交通、船舶航运等行业的发展,各类设备的制造不断向高速度、高负载、高精度、高性能等方向发展,设备运行而引发的噪声问题逐渐走入了人们的视野。强烈的噪声会影响军工设备的精度与隐蔽性,降低城市中轨道交通环境的舒适性,以及危害人们的健康与生活,因此对噪声的控制问题继续解决。然而低频段的噪声以其穿透能力强的特点使得传统吸声结构难以将其吸收,而声学超材料基于局域共振原理可以实现在亚波长尺度结构下对低频声波的吸收,为了进一步提高声学超材料的吸声性能,本文提出一种新型的内嵌预压双稳屈曲梁的薄膜型声学超材料。本文首先对具有双稳态特性的非线性预压双稳屈曲梁结构单元的跳转特性进行了理论分析,研究了梁轴向力,径向力,初始拱高,跳跃幅值之间的关系,并通过商用有限元软件ABAQUS进行非线性仿真模拟,分析了梁结构参数和预应力对临界跳转力、预压轴向位移、最大最小刚度、应变能等跳转特性的影响。之后基于Bloch理论分析了声学超材料单胞带隙的形成机理,采用基于COMSOL软件的有限元方法和平面波展开法对单胞进行频散关系特性分析,结果基本一致,验证了计算方法的正确性。然后对单胞进行模态分析,进一步研究了局域共振机理,并以此为依据,探究了单胞的结构参数和材料参数,以及内嵌双稳屈曲梁的结构参数和预应力对带隙的影响。然后构造了有限周期排列的内嵌预压双稳屈曲梁的薄膜声学超材料结构,分析了添加完美匹配层PML域的必要性,并计算结构的声波传输响应,与频散关系对比验证了计算的正确性,研究了结构的单胞个数以及材料的阻尼对其吸声性能的影响。后对结构中的双稳梁施加预应力,进行非线性瞬态响应分析,探究预应力对结构隔声性能的影响。研究表明,预压双稳屈曲梁的引入不仅可以有效的降低薄膜声学超材料的带隙频率,还能够显著的增强其隔声性能。更多还原

【Abstract】 With the development of military industry,aerospace,urban rail transportation and otherindustries,the manufacture of various types of equipment continues to develop toward high speed,light weight,large size,heavy load and extreme operating environments.The noise problems caused by the operation of equipment have gradually entered the people Vision.Strong noise will affect the accuracy and concealment of military equipment,reduce the comfort of the rail transit environment in the city,and endanger people’s health and life,so the problem of noise control continues to be solved.However,due to its strong penetration ability,low-frequency noise makes it difficult for traditional sound-absorbing structures to absorb it.Acoustic metamaterials can realize the absorption of low-frequency sound waves in sub-wavelength scale structures based on the principle of local resonance.For the sound absorption properties of metamaterials,this paper proposes a new type of membrane-type acoustic metamaterial with embedded prestressed bistable buckling beam.In this paper,the theoretical analysis of the jump characteristics of the nonlinear prestressed bistable buckling beam structural element with bistable characteristics is carried out.The relationship between the beam axial force,radial force,initial arch height and jump amplitude is studied.In addition,the nonlinear finite element simulation of commercial finite element software ABAQUS was used to analyze the influence of beam structural parameters and prestress on critical jump force,preload axial displacement,maximum and minimum stiffness,strain energy and other jump characteristics.Then,based on Bloch theory,the formation mechanism of the band gap of acoustic metamaterial unit cells was analyzed.The finite element method based on COMSOL software and plane wave expansion method were used to analyze the dispersion relationship characteristics of unit cells.Then,the modal analysis of the membrane acoustic metamaterial unit cell was carried out to further study the local resonance mechanism,and on this basis,the structural parameters and material parameters of the unit cell,as well as the structural parameters and embedded bistable buckling beam structural parameters and The effect of prestress on the band gap.Then a thin-film acoustic metamaterial structure with prestressed bistable buckling beams with finite period arrangement is constructed,the necessity of adding a perfect matching layer PML domain is analyzed,and the acoustic transmission response of the structure is calculated,which is verified by comparison with the dispersion relationship.The correctness of thecalculations was studied on the influence of the number of unit cells of the structure and the damping of the material on its sound absorption performance.After prestressing the bistable beams in the structure,a nonlinear time-domain response analysis is conducted to explore the effect of prestressing on the sound insulation performance of the structure.Studies have shown that the introduction of prstressed bistable buckling beams can not only effectively reduce the band gap frequency of membrane acoustic metamaterials,but also significantly enhance its sound insulation performance.更多还原