基于Hilbert-Huang变换的海洋平台结构损伤识别研究

Study on Damage Detection of Offshore Platforms Based on Hilbert-Huang Transform

海洋平台在服役期间,由于各种因素的影响会出现不同程度的损伤,这些损伤不断累积,对结构安全造成了极大威胁。利用通用有限元分析软件ANSYS对波流联合作用下的导管架平台模型进行瞬态动力学分析,通过MATLAB编程实现对动力响应信号的Hilbert-Huang变换,得到信号的固有模态函数(IMF)、Hilbert谱和Hilbert边际谱。提出以损伤前后信号Hilbert边际谱置信度作为损伤指标,分析对比不同损伤程度下该损伤指标的有效性,并探讨了采样数据长度和波浪参数对该损伤指标的影响。研究结果可以为后续研究和工程应用提供参考。

During the service period, the impact of various factors will cause different de- grees of damage on offshore structure, the damage is accumulated, which constitutes a great threat to the safety of structures. The model of the jacket platform was established by finite el- ement software ANSYS,and the transient dynamic analysis was carried out under the loads of combined wave-current. The Hilbert-Huang transform of the dynamic response signals were realized by MATLAB programming. The Intrinsic Mode Function, Hilbert spectrum and Hil- bert marginal spectrum of signals were obtained. On the selection of the damage index, it con- structs the damage index based on the confidence coefficient of Hilbert marginal spectrum. Based on this damage index, the effectiveness of damage detection was investigated and four cases were considered, including different damage degrees, different data lengths, different wave height and different wave period. The research results provides a reference approach for further study and engineering application.