基于Hybrid FE-SEA结构中频声振疲劳分析方法研究

发布时间：2018-06-19 07:15

本文选题：Hybrid + FE-SEA方法　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：飞行器、舰船和汽车常处于宽频噪声环境之中,若处理不当,这种环境引起的振动易导致金属蒙皮、舰艇外壳和白车身等板类结构产生疲劳破坏。宽频声振耦合问题一般分为低、中、高三个频段分别进行求解。对于其中的中频声振耦合问题,组合结构动态特性差异比较大,单独使用低频确定性方法或高频统计能量方法均不能有效地进行声振响应预示。针对此频段特征,近年来提出了 Hybrid FE-SEA方法。该方法自提出至今已成功解决了很多工程问题。但是,对于Hybrid FE-SEA方法中重要参数,如有效耦合损耗因子等,目前还缺乏深入研究。而现今结构的声振疲劳分析也主要集中于低频段,在Hybrid FE-SEA分析的基础上进行结构较高频段激励下的疲劳分析还未有人涉足。本文,以典型板类结构为分析对象,对Hybrid FE-SEA方法中有效耦合损耗因子作深入研究,并探究基于Hybrid FE-SEA的结构中频声振疲劳分析方法。论文具体工作如下:1.Hybrid FE-SEA方法的验证及应用系统总结了基于波动耦合的Hybrid FE-SEA方法基本理论,根据Hybrid FE-SEA方法群体平均的思想,采用蒙特卡洛方法验证了 Hybrid FE-SEA分析中频声振耦合问题的有效性,最后以梁板组合结构为算例,进行了此结构中频声振特性分析。2.有效耦合损耗因子的结构参数敏感度研究有效耦合损耗因子是Hybrid FE-SEA方法中的重要参数之一,它反映了子系统间功率流的传递。本文介绍了有效耦合损耗因子的基本理论,并分析了线连接情况下各子系统间有效耦合损耗因子大小。最后考察了板和梁结构参数变化对有效耦合损耗因子的影响,得到的规律对优化子系统间能量传递具有指导意义。3.基于Hybrid FE-SEA的结构中频声振疲劳分析方法研究板类结构是飞行器、舰船、汽车等的典型构件,常处于宽频噪声环境中,其中频段激励成份常较丰富,由此引起的中频声振疲劳问题不能忽略。采用频域法进行声振疲劳分析需要结构危险点应力功率谱密度。由于Hybrid FE-SEA分析得到的是位移、速度、能量等响应,因而不能直接用于结构的中频疲劳分析。本文根据Hybrid FE-SEA方法获得的位移和能量响应推导各子系统应力响应,结合Dirlik零阶矩应力谱法,形成了结构中频激励下声振疲劳分析方法,并采用FEM分析验证了此方法的正确性。最后,给出了加筋板在宽频激励下的声振疲劳分析,结果显示,中频激励下的响应结果对宽频段疲劳损伤量的贡献不能忽略。
[Abstract]:Aircraft, ships and cars are often in the environment of wide-band noise. If the environment is not handled properly, the vibration caused by this kind of environment will easily lead to metal skin, ship shell and white body and other plate structure fatigue damage. The wide band acoustic-vibration coupling problem is generally divided into three frequency bands: low, middle and high. For the intermediate frequency acoustic vibration coupling problem, the dynamic characteristics of the composite structure are quite different, so it is not possible to predict the acoustic vibration response by using the deterministic method of low frequency or the statistical energy method of high frequency alone. Hybrid FE-SEA (Hybrid FE-SEA) method is proposed for this frequency band in recent years. This method has successfully solved many engineering problems since it was put forward. However, the important parameters of Hybrid FE-SEA, such as the effective coupling loss factor, are not well studied. At present, the acoustic and vibration fatigue analysis of structures is mainly focused on the low frequency band. Based on Hybrid FE-SEA analysis, fatigue analysis under high frequency band excitation has not been explored. In this paper, the effective coupling loss factor in Hybrid FE-SEA method is deeply studied, and the hybrid FE-SEA based structure mid-frequency acoustic vibration fatigue analysis method is explored. The main work of this paper is as follows: 1. The verification and application of Hybrid FE-SEA method. The basic theory of Hybrid FE-SEA method based on wave coupling is summarized. According to the idea of population average of Hybrid FE-SEA method, Monte Carlo method is used to verify the effectiveness of hybrid FE-SEA in the analysis of intermediate frequency acoustic-vibration coupling problem. Finally, taking the beam-plate composite structure as an example, the intermediate frequency acoustic and vibration characteristics of the hybrid FE-SEA structure are analyzed. Study on the sensitivity of structural parameters of the effective coupling loss factor is one of the important parameters in the Hybrid FE-SEA method which reflects the transfer of power flow between subsystems. In this paper, the basic theory of effective coupling loss factor is introduced, and the magnitude of effective coupling loss factor between subsystems is analyzed in the case of line connection. Finally, the influence of the structural parameters of plate and beam on the effective coupling loss factor is investigated. The obtained rule is of guiding significance for optimizing the energy transfer between subsystems. Hybrid FE-SEA based structure Analysis method for Intermediate Frequency Acoustic Vibration fatigue; Plate structures are typical components of aircraft, ships, automobiles and so on, which are often in the environment of wide-band noise, among which the excitation components in the frequency band are often abundant. The problem of if-frequency vibration fatigue can not be ignored. The frequency domain method for acoustic-vibration fatigue analysis requires the stress power spectral density of structural danger point. Hybrid FE-SEA analysis can not be directly used in intermediate frequency fatigue analysis because of the displacement, velocity and energy response. Based on the displacement and energy responses obtained by Hybrid FE-SEA method, the stress responses of each subsystem are deduced in this paper. Combined with the Dirlik zero-order moment stress spectrum method, an acoustic fatigue analysis method under intermediate frequency excitation is developed, and the correctness of the method is verified by FEM analysis. Finally, the sonic vibration fatigue analysis of stiffened plates under wide-band excitation is given. The results show that the response results under intermediate frequency excitation can not ignore the contribution of the response results to the wide-band fatigue damage.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O346.2;O327

【相似文献】