论文总字数：29945字

摘 要

飞行器在高速飞行中，面临着严峻的高强、宽带噪声环境。飞行器中包含的大量薄壁构件在高强、宽带噪声环境下容易产生声振疲劳破坏；此外，结构内设置的某些精密仪器、仪表等器件在高频噪声环境容易失灵，进而使得飞行器无法正常运行。因此，在飞行器设计过程中，须考虑高强、宽带噪声环境的影响。本文旨在实现基于统计能量法的典型结构高频动响应分析及结构优化。

本文首先介绍了统计能量法的基本理论，包括统计能量法基本方程、各统计能量分析参数的涵义、子系统划分依据、统计能量法的相关假设条件及其适用范围。而后介绍了各统计能量分析参数的理论计算方法。具体包括：（1）典型结构或子系统（杆、梁、平板、蜂窝板、圆柱薄壳、声腔等）的模态密度的计算方法；（2）子系统内损耗因子（包含结构损耗因子、声辐射损耗因子、边界摩擦损耗因子）的计算方法；（3）典型连接（点连接、线连接、面连接）的耦合损耗因子的计算方法；（4）典型激励源（点源、线源、面源）的输入功率的计算方法。接下来，基于统计能量法分析了一个卫星承力筒-蒙皮典型结构的动响应。具体考虑了三种工况：（1）在卫星外蒙皮上施加宽屏噪声激励（50~8000Hz）；（2）在卫星承力筒基座上施加中低频基础激励（50~2000Hz）；（3）同时将上述两种激励施加于该卫星承力筒-蒙皮典型结构。对于该卫星承力筒-蒙皮典型结构，分析结果表明：在2000Hz以内，该随机基础激励引起的系统响应的量级大于该噪声激励引起的系统响应的量级；在上述两种特定载荷共同作用下，随机基础激励对系统在2000Hz以内的响应起决定性作用，噪声激励对系统在2000Hz以上的响应起决定性作用。最后，基于统计能量法对上述卫星承力筒-蒙皮典型结构进行了优化设计，以降低主要声腔的高频段噪声水平，进而提高声腔内精密仪器、仪表等器件正常工作的可靠性。所采取的降噪措施为在声腔某些直接受噪声激励的壁板内侧铺设一层具有隔声、吸声功能的轻质玻璃纤维棉（与声腔接触面铺设有起防护作用的硬橡胶薄板），具体考虑了下述三种降噪方案：方案一，在结构侧蒙皮内侧铺设降噪材料；方案二，在结构顶蒙皮内侧铺设降噪材料；方案三，在结构侧蒙皮及顶蒙皮内侧铺设降噪材料。优化变量为：轻质玻璃纤维棉层的厚度；目标函数为：在尽可能少用降噪材料的前提下尽可能多地降低主要声腔内噪声水平。分析结果表明，方案一的综合降噪效果最好。通过优化设计，得到最优降噪方案：在侧蒙皮内侧铺设10 mm厚的轻质玻璃纤维棉，此时结构增加了2.07%的质量，而主要声腔的噪声水平降低到采取降噪措施前的40%。

以上研究表明，统计能量法是一种有效的高频动响应分析方法，可用于高强、宽带噪声环境下结构的动响应预示及优化设计。

关键词：统计能量分析；承力筒—蒙皮结构；动响应分析；结构优化设计

ABSTRACT

In the high speed flight, the aircraft is faced with severe high strength and wide band noise environment. A large number of thin wall components which are contained in the aircraft are easy to produce acoustic vibration fatigue damage under high strength and wide band noise environment. In addition, certain precision instruments, instruments and other devices which are arranged inside the aircraft structure are easy to failure in the high frequency noise environment, which makes the aircraft can't normally operate. The influence of the high strength and wide band noise environment must be taken into account in the process of aircraft design. This paper aims to realize high frequency dynamic response analysis and structural optimization of typical structures based on statistical energy method.

This paper introduces the theoretical calculation method of the statistical energy analysis parameters. Specific include: (1)the calculation method of modal density of the typical structure or subsystem, (2) the calculation method of loss factor, (3) the calculation method of the coupling loss factor of a typical connection, (4) the calculation method of the input power of the typical excitation source. And based on the statistical energy method, the dynamic response of the typical structure of a satellite bearing shell is analyzed. Specifically to consider the three conditions: (1) High frequency noise excitation (50~8000Hz) is applied on the outer skin of the satellite; (2) Medium and low frequency excitation (50~2000Hz) is applied on the base of the satellite. (3) The above two kinds of excitation is applied to the typical structure of the satellite at the same time. For the satellite bearing cylinder skin typical structure, the analysis results show that: within the 2000Hz, the magnitude of the system response caused by the random base excitation is larger than the order of magnitude of the system response caused by the noise excitation. Under the combined action of the above two kinds of loads, the random foundation excitation plays a decisive role in the response of the system within 2000Hz, and the noise excitation plays a decisive role in the response of the system above 2000Hz. Finally, based on the statistical energy method, the optimal design of the typical structure of the satellite is carried out to reduce the high-frequency noise level of the main tune, and improve the precise instruments and instrumentation in tune, the normal working of the device reliability. Take measures to reduce noise is laying a layer of sound insulation, sound-absorbing function of lightweight glass fiber cotton (contact with the tune the noodle shop has protective effect of hard rubber sheet) on the inner side of the tune panel which directly affected by noise excitation. Specifically to consider the following three kinds of noise reduction scheme, Program one, laying noise reduction materials on the inner side of the structure side skin. Program two, laying noise reduction material on the inner side of the top of the structure. Program three, laying noise reduction material on the inner side of the structure side and the inner side of the top skin. The analysis results show that the program one has the best noise reduction effect. Laying of 10 mm thick lightweight glass fiber cotton in the inner side of the side skin and at the same time the structure increases the quality of 2.07%, and the noise level of main tune has decreased by 40%.

The above research shows that the statistical energy method is an effective method for high frequency dynamic response analysis, which can be used to predict the dynamic response of structures in high strength and wide band noise environment.

Key words: Statistical Energy Analysis; bearing tube - skin structure; dynamic response analysis; optimization design

目录

摘要 1

ABSTRACT 2

第1章 绪论 5

1.1 研究的目的和意义 5

1.2 国内外研究现状 5

1.3 本文研究的主要内容 6

第2章 统计能量分析方法基本理论 7

2.1 引言 7

2.2 统计能量法基本方程 7

2.3 统计能量分析相关假设及适用范围 9

2.3.1 相关假设 9

2.3.2 适用范围 9

2.4 小结 9

第3章 统计能量分析的参数确定 11

3.1 引言 11

3.2 模态密度的确定 11

3.2.1 均匀杆的纵向振动系统的模态密度^[33] 11

3.2.2 标准梁的横向振动系统的模态密度 12

3.2.3 弯曲振动平板的模态密度 12

3.2.4 三维声场的模态密度 12

3.2.5 圆柱薄壳模态密度 12

3.2.6 蜂窝夹层结构的模态密度 13

3.3 内损耗因子的确定 13

3.3.1 结构损耗因子 14

3.3.2 声辐射损耗因子 14

3.3.3 边界摩擦损耗因子 14

3.4 耦合损耗因子的确定 15

3.4.1 点连接的耦合损耗因子 15

3.4.2 线连接结构之间耦合损耗因子 15

3.4.3 面连接子系统之间耦合损耗因子 15

3.5 输入功率的确定 16

3.5.1 点源的输入功率 16

3.5.2 线源的输入功率 17

3.5.3 面源的输入功率 17

3.6 小结 18

第4章 卫星承力筒—蒙皮典型结构统计能量分析 19

4.1 引言 19

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