无穷大二维周期加强板的声振特性研究

发布时间：2018-06-15 13:04

本文选题：周期加强板 + 振动响应　；参考：《大连理工大学》2013年博士论文

【摘要】：周期加强板结构广泛应用于机械工程、航空航天、船舶潜艇和车辆工程等领域,因而与其相关的振动及声学特性的研究具有十分重要的工程价值。为了深入分析周期加强板的声振特性,本文对其振动响应、声辐射、反射和透射等性质进行了系统研究,并对周期加强的微穿孔板的吸声性能进行了分析。其中主要研究内容包括： (1)综合运用空间波数法、格林函数、泊松迭加公式和傅里叶变换等数学方法分析了流体负载下的,异向正交周期加筋和同向双周期加筋两种不同类型加筋薄板结构在谐振面力作用下的振动响应和声辐射。对于异向正交周期加筋薄板,采用空间波数法将其振动位移及辐射声压表达为一系列谐波分量的迭加。对于同向双周期加筋薄板,利用分量迭加公式及结构周期性质,求解得到其振动位移及辐射声压方程。同时分析了加强筋对薄板的法向力作用及扭矩作用。计算结果表明周期加强筋在中低频域区间起到了降低薄板辐射声压的作用。 (2)研究了流体负载下的不同类型双周期加强薄板,在谐振面力激励下的振动响应和声辐射,并提出了一种基于有限元和空间波数法的半解析半数值方法；附加的周期结构可以是包含筋在内的任意不同形状的结构。为了得到不同类型周期结构与薄板间的作用力,基于有限元的思想对周期结构进行单元离散,将薄板与周期结构的面力等效为离散节点力的作用,并最终将周期加强板的振动位移和辐射声压方程表达为薄板离散点位移的函数。运用加强板结构周期性质及空间波数理论,在实际分析时只需要计算一个周期单元的离散点位移,有效地降低了计算工作量。 (3)分别通过均匀等效模型和周期模型两种建模方法研究了双周期肋骨连接的双层板结构的反射和透射声压；并在单层周期加筋板的基础上,对另外一种类型的拉杆连接的双层周期加筋板结构采用周期模型方法进行了研究。双层薄板结构附加周期连接肋后增加了结构的平均反射声压而降低了其透射声压。拉杆对双层加筋板结构反射和透射声压的影响主要是在几千赫兹内的中低频域区间。 (4)采用耦合法和级联法两种方法研究了单层及多层双周期加强板的透声系数。耦合法是同时对整体多层加强板结构进行分析,并将所有声振未知量在统一的矩阵方程中计算求解得到。级联法是首先分析单层板结构的振动及声压方程,并在此基础上通过声波的空间传播性质以及各层板声压矩阵的级联得到整体多层结构的反射及透射声压系数矩阵。在水中环境下加强板结构的弯曲振动作用显著,且周期结构起到了降低结构透声系数的作用。 (5)基于微穿孔板相关声学理论的基本公式,研究了周期加强微穿孔板的吸声性质,并在单层板结构反射与透射系数矩阵的基础上,通过级联的方法进一步分析了多层周期加强微穿孔板的吸声特性,并与单层结构进行了比较。分析结果表明,水中周期加强的微穿孔板的吸声性能远高于未加强的微穿孔板的吸声性能,多层板结构具有比单层结构更优良的吸声性能,且吸声系数随穿孔板层数的增加而增大。通过对薄板加工微孔和附加适当周期结构的方法可以有效地提高水下薄板的吸声性能,对吸声结构的设计和研究具有重要价值。
[Abstract]:Periodic stiffened plates are widely used in the fields of mechanical engineering, aeronautics and Astronautics, ship submarines and vehicle engineering and so on. Therefore, the study of its related vibration and acoustic characteristics is of great engineering value. In order to analyze the acoustic vibration characteristics of the periodic reinforced plate, the characteristics of its vibration response, sound radiation, reflection and transmission are carried out in this paper. The sound absorption properties of perforated panels strengthened by cycle are analyzed.
(1) by using the spatial wave number method, Green's function, Poisson superposition formula and Fu Liye transform, the vibration response and sound radiation of two different types of stiffened plates under the action of resonance surface force under the fluid load are analyzed under the fluid load. The vibration displacement and the sound pressure are expressed as a series of harmonic components by the spatial wave number method. The equation of vibration displacement and sound pressure is obtained by using the component superposition formula and the periodic properties of the structure for a double cycle stiffened plate with same direction. At the same time, the normal force action and the torque effect of the stiffeners to the thin plate are analyzed. The calculation results are also analyzed. It shows that the periodic stiffeners play a role in reducing the sound pressure of the thin plate in the middle and low frequency range.
(2) the vibration response and acoustic radiation of different type double periodic stiffened plates under the fluid load under the excitation of the resonant surface force are studied. A semi analytical and semi numerical method based on the finite element method and the space wave number method is proposed. The additional periodic structure can be a structure with any different shapes including the reinforcement. The force between the periodic structure and the plate is discretized on the periodic structure based on the thought of the finite element, and the surface force of the plate and the periodic structure is equivalent to the discrete node force. Finally, the vibration displacement and the radiation pressure equation of the periodic stiffened plate are expressed as the function of the discrete point displacement of the thin plate. And the theory of spatial wavenumbers, in actual analysis, we only need to calculate the discrete point displacement of a periodic unit, which effectively reduces the computational workload.
(3) the reflection and transmission sound pressure of double periodic ribs connected by double periodic ribs are studied by the two modeling methods of uniform equivalent and periodic model, and on the basis of a single layer periodic stiffened plate, the periodic model method is used to study the double deck stiffened plate structure connected by another type of pull rod. The average reflected sound pressure of the structure is increased after the additional periodic connection of the structure, and the transmission sound pressure is reduced. The influence of the pull rod on the reflection and transmission sound pressure of the double stiffened plate structure is mainly in the middle and low frequency range in the thousands of Hertz.
(4) the coupling method and cascade method are used to study the sound permeability coefficient of single layer and multilayer double periodic stiffened plate. The coupling method is used to analyze the overall multilayer stiffened plate structure and calculate all the acoustic vibration unknown in a unified matrix equation. The cascade method is the first analysis of the vibration and sound pressure equation of the single layer plate structure. On this basis, the reflection and transmission sound pressure coefficient matrix of the whole multilayer structure is obtained by the spatial propagation properties of sound wave and the cascade of the sound pressure matrix of various laminates. The flexural vibration of the plate structure is strengthened in the water environment, and the periodic structure plays a role in reducing the sound permeability coefficient of the structure.
(5) based on the basic formula of the related acoustic theory of microperforated plate, the sound absorption properties of the periodically strengthened microperforated plate are studied. On the basis of the reflection and transmission coefficient matrix of the single layer plate structure, the sound absorption characteristics of the multilayer periodic reinforced micro perforated plate are further analyzed by cascade method, and the comparison with the single layer structure is made. It is clear that the sound absorption property of the micro perforated plate strengthened by the water cycle is much higher than that of the unreinforced micro perforated plate. The multilayer plate structure has better sound absorption properties than the single layer structure, and the sound absorption coefficient increases with the increase of the number of perforated plates. The sound absorption property of underwater thin plate is of great value to the design and research of sound absorption structure.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TB533;TH113.1

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