【作者】 汪家慰；

【导师】 刘正士；

【作者基本信息】 合肥工业大学 ， 机械设计及理论， 2010， 硕士

【摘要】 本文围绕着新型信号处理方法Hilbert-Huang变换(HHT),对HHT变换理论及其在结构动态性能分析中的应用进行了较为全面系统的研究。首先,文章介绍了HHT变换的基本理论,对经验模态分解(EMD)理论和Hilbert变换进行了详细的阐述。由于HHT变换理论自身没有建立严格的数学理论基础,在实际应用中存在多种问题。本文对其中的模态混淆现象、固有模态判据问题、包络拟合方法和端点效应问题等问题进行了相关研究,提出了相应的改进方法,通过数值仿真说明了改进方法是有效的。其次,在对HHT变换理论详细研究的基础上,针对应用HHT变换理论识别结构的振动模态参数进行了主要研究。包括应用HHT变换从结构的动力响应中识别结构的模态频率、模态阻尼比、模态振型以及如何分离出密集模态等方面进行了研究,得出了一些有益的结论。最后,通过对悬臂梁结构进行模态试验分析测得悬臂梁结构的动力响应数据,然后应用HHT变换识别出悬臂梁结构的结构振动模态参数,验证HHT方法识别模态参数的有效性。更多还原

【Abstract】 The theory of Hilbert-Huang Transform and its application in the analysis of the structural dynamic performance are comprehensively and systematically studied in this article.Firstly, the theory of the empirical mode decomposition and Hilbert transform are illustrated in detail. Because the strict mathematical theoretical basis hasn’t been developed in HHT, many of problems may be encountered in its practical application such as the intrinsic mode function stop criterion,end effects,mode confusion and envelope fitting method. Some studies of these problems are made, and some improvements are presented to heighten the performance of the EMD. Numerical simulations demonstrate the validity of these improvements.Secondly, based on the HHT which is well-studied, the theory of HHT is applied to identify the vibration modal parameters such as modal frequency, modal damping ratio and modal shape from the dynamic response data of the structures. Some promising conclusions are achieved.Finally, modal testing is carried out to cantilever beam to collect structural dynamic corresponding data, then applying HHT to identify the modal parameters of the cantilever beam. The results show the effectiveness and validity of the HHT method更多还原