基于小波分析的Spar平台阻尼系数研究

连续小波分析方法作为典型的时频方法虽已广泛应用于工程界，但在海洋工程领域并未得到大力推广。文章应用连续小波分析方法对海洋工程领域中与Truss Spar平台涡激运动相关的阻尼系数进行求解。通过构建测试信号对这一方法进行数值检验，验证了小波分析方法的可靠性和准确性。利用试验数据，成功将小波分析方法应用于求解Truss Spar平台阻尼系数问题中。结果表明小波分析方法具有较好的可靠性，能够准确求解平台的阻尼系数。

Study of Damping Ratio Identification for a Truss Spar Based on Continuous Wavelet Transform

Damping and frequency are the crucial hydrodynamic parameters in predicting Vortex-In-duced Motion (VIM) of a Truss Spar. The continuous wavelet transform (CWT) is a typical time-fre-quency method based on the Gabor wavelet function, which is widely used in the engineering field except ocean engineering. This paper applied a CWT method to identify the damping ratio of VIM in ocean engineering. CWT method which is resistant to noise is able to estimate the multi-mode damp-ing ratios and identify damping ratios at closely spaced natural frequencies. Applications to both analytical and experimental data of free-decay were made. The results were compared to the exact values in the case of analytical data and to those estimated by the exponential method in the case of experimental data. Eight different free-decay tests were conducted in still water to provide sufficient data sets. Both analytical and experimental results indicate that the proposed method can be used to achieve more accurate identification of modal parameters in VIM field of ocean engineering.