层合板结构声振特性及声辐射最小化优化分析

发布时间：2018-05-16 07:13

本文选题：复合材料层合板 + 分层理论　；参考：《南昌航空大学》2015年硕士论文

【摘要】：复合材料层合板结构因其比模量大,比强度高,抗疲劳性能好,可设计性和低噪声性,被广泛应用于航空航天、船舶汽车制造等工业领域。复合材料层合板结构在实际工程运用中难免受到外界激励产生受迫振动,并向周围辐射声,产生噪声污染。而层合板结构振动一般处于中低频段,其声辐射特性与自身结构参数、激励位置及激励频率有关。因此,研究层合板结构在中低频时的声振特性,对噪声控制具有重要意义和实际价值。本文将以复合材料层合板结构为对象,对其受迫振动及声辐射性能展开研究。首先,对复合材料层合板的振动特性进行理论推导。本文采用分层理论结合有限元的方法,计算层合板结构的各阶固有频率、结构振型以及在外激励下的动态响应。通过数值模拟与参考文献中的解析解及其它理论计算结果进行对比,验证分层理论计算固有频率的精确性。其次,基于分层理论计算层合板结构的声辐射模态伴随系数及辐射声功率,并在单点及两点激励下分别对层合板的声辐射特性进行研究。分析了截断模态数目、层合板的铺设角度、激励点位置、激励频率对声辐射模态系数幅值及辐射声功率的影响。结果表明,层合板结构的铺设角度、激励位置及激励频率对层合板的声振特性有不同程度上的影响。最后,基于遗传算法对层合板结构声辐射的最小化进行优化分析。在理论上,计算声辐射模态伴随系数需要整个板表面的振动速度信息,但在实际工程中难以实现且意义不大。由于声辐射模态存在正交性,文中通过测量有限点的速度,利用最小二乘法来获取前N阶声辐射模态伴随系数近似值,进而对声辐射最小化进行分析。并基于遗传算法对有限测量点进行优化,以实现控制声辐射的最小化。
[Abstract]:Because of its large specific modulus, high specific strength, good fatigue resistance, good design and low noise, composite laminates are widely used in aerospace, shipbuilding and other industrial fields. The composite laminates are difficult to avoid forced vibration from external excitation in the practical application of the composite laminates, and produce noise from the surrounding area and produce noise. The vibration of laminates is generally in the middle and low frequency segments, and the acoustic radiation characteristics are related to their own structural parameters, the excitation position and the excitation frequency. Therefore, the study of the acoustic vibration characteristics of the laminate structure at low and low frequencies is of great significance and practical value for the noise control. The vibration and acoustic radiation performance are studied. First, the vibration characteristics of composite laminates are theoretically derived. In this paper, the hierarchical theory and finite element method are used to calculate the natural frequencies of each order of the laminate structure, the structure mode and the dynamic response under the external excitation. The theoretical calculation results are compared to verify the accuracy of the inherent frequency of the stratified theory. Secondly, based on the stratification theory, the acoustic radiation mode adjoint coefficient and radiation power are calculated, and the acoustic radiation characteristics of the laminates are studied under single and two excitation. The number of truncated modes and the laminates are analyzed. The effect of the laying angle, the position of the excitation point and the excitation frequency on the amplitude of acoustic radiation modal coefficient and the radiation sound power. The results show that the laying angle of the laminate structure, the excitation position and the excitation frequency have different influence on the acoustic vibration characteristics of the laminate. Finally, the optimization of the acoustic radiation of the laminate structure is optimized based on the genetic algorithm. In theory, the calculation of the adjoint coefficient of acoustic radiation mode needs the information of the vibration velocity of the whole surface of the plate, but it is difficult to realize in the actual project and has little significance. Because of the orthogonality of the acoustic radiation mode, the approximate value of the adjoint coefficient of the former N order acoustic radiation mode is obtained by measuring the velocity of the finite point in the paper. The minimum acoustic radiation is analyzed, and the limited measurement points are optimized based on genetic algorithm to minimize the acoustic radiation.

【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TB53

【参考文献】