基于相干函数的海上风电支撑结构非线性损伤识别实验研究
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摘要
文章研究了基于相干函数的海上风电支撑结构非线性损伤识别方法。为了克服传统相干函数法的不足,提出了一种仅利用结构振动响应信号的相干性分析方法。基于此,定义了相对损伤函数和局部相对损伤函数,构建了一种损伤检测指标和一种损伤定位指标。对于带宽或频谱成分不同的信号,采用了一种两阶段解析模式分解法进行信号处理。为验证方法的有效性和实用性,对单立柱式海上风电支撑结构开展了非线性损伤识别实验研究。结果表明:所提出的基于相干函数的非线性损伤检测指标可灵敏地指示结构非线性损伤的发生及相对损伤程度;损伤定位指标可以准确地识别结构的损伤单元。
The nonlinear damage identification method based on coherence function is studied for support structures of offshore wind turbines. To overcome the shortcomings of the traditional coherent function, a coherent analysis method only-using vibration response signals is proposed.Based on coherence function, a relative damage function and a local relative damage function are defined. Then, a damage detection index and a damage localization index are constructed. For signals with different bandwidth or spectrum components, a two-step analytical mode decomposition method is used for signal preprocessing. In order to verify the effectiveness and practicability of the new method, a nonlinear damage identification experimental study is carried out on a monopile offshore wind turbine support structure. Results show that the nonlinear damage detection index can sensitively indicate the occurrence and relative damage level of the nonlinear structural damage, and the damage localization index can accurately identify the damage element of the structure.
The nonlinear damage identification method based on coherence function is studied for support structures of offshore wind turbines. To overcome the shortcomings of the traditional coherent function, a coherent analysis method only-using vibration response signals is proposed.Based on coherence function, a relative damage function and a local relative damage function are defined. Then, a damage detection index and a damage localization index are constructed. For signals with different bandwidth or spectrum components, a two-step analytical mode decomposition method is used for signal preprocessing. In order to verify the effectiveness and practicability of the new method, a nonlinear damage identification experimental study is carried out on a monopile offshore wind turbine support structure. Results show that the nonlinear damage detection index can sensitively indicate the occurrence and relative damage level of the nonlinear structural damage, and the damage localization index can accurately identify the damage element of the structure.
引文
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[3] Ebrahimian H,Astroza R,Conte J P,et al.Nonlinear finite element model updating for damage identification of civil structures using batch Bayesian estimation[J].Mechanical Systems&Signal Processing,2017,84:194-222.
[4]段忠东,闫桂荣,欧进萍.土木工程结构振动损伤识别面临的挑战[J].哈尔滨工业大学学报,2008,40(4):505-513.
[5] Farrar C R,Worden K,Todd M D,et al.Nonlinear system identification for damage detection[R].Los Alamos:Los Alamos National Laboratory,2007.
[6]张宇飞,王山山,甘水来.基于随机振动响应相干函数的梁结构损伤检测[J].振动与冲击,2016,35(11):146-150.
[7] Dunn P F,Michael P D.Measurement and Data Analysis for Engineering and Science(4th Edition)[M].Boca Raton:CRC Press,2017.
[8] Worden K,Tomlinson G R.Nonlinearity in Structural Dynamics:Detection,Identification and Modelling[M].Bristol:Institute of Physics Publishing,2001.
[9] Li Y,Zhang M,Yang W.Numerical and experimental investigation of modal-energy-based damage localization for offshore wind turbine structures[J].Advances in Structural Engineering,2018,21(10):1510-1525.
[10] Hu Z,Wang Z,Ren W,et al.On the analytical mode decomposition theory and algorithm for discrete vibration signal processing[J].Journal of Vibration Engineering,2016,29(2):348-355.