摘要
针对海上风电结构,研究了环境激励下海上风电结构的模态参数识别问题。采用了一种时域联合算法:自然激励法(Natural Excitation Technique,简称NExT)和多参考点复指数法(Polyreference Complex Exponential,简称PRCE)的结合(简称NExT/PRCE方法)对海上风电结构的模态参数进行识别。对某三脚架式海上风电结构进行数值模拟,考虑了风电结构的实际操作工况,对结构施加了随机波浪荷载和风机载荷。利用动力响应数据进行了环境激励下风电整体结构模态参数识别,采用了稳定图与模态置信准则进行了虚假模态的剔除,并分析了NExT中参考通道选取对于模态参数识别效果的影响。通过与有限元模型模态参数比较,验证了NExT/PRCE方法对于风电结构参数识别的有效性。
Offshore wind energy has a broad prospect of application as a green pollution-free clean energy to ease global warming. The offshore wind turbine structures are the basic facilities for offshore wind en- ergy exploitation. During the service life, damages of the foundation structures are unavoidable as a result of the action of various loads including operational and environmental forces. The damage may result in a significant change in the modal properties of the structure, such as natural frequencies and mode shapes. Thus, the modal parameter estimation, which is the process of determining modal parameters from re- sponse data, of an offshore wind turbine structure, is the essential step for structure health monitoring (SHM). The offshore wind turbine structures are subject to ambient excitation from sources such as wind, waves etc. The input ambient excitation is often unmeasurable. Therefore, the modal parameters of these structures must be identified by output-only modal identification methods. In this paper, modal pa- rameter identification for offshore wind turbine is studied. A time-domain modal identification method which combined Natural Excitation Technique (NEXT) and Polyreference Complex Exponential (PRCE) method (called NExT/PRCE method for short) is applied to identify modal parameters under ambient ex- citation. Numerical example applied a tripod-type offshore wind turbine structure. Considering the opera- tional condition of the structure, the dynamic analysis was performed under simulated random wave load and wind turbine load. The modal frequencies and corresponding mode shapes were identified from the ob- tained time histories of response signals. Stability diagram and MAC value were set to eliminate the false modes. And the influence of the chosen reference channel on modal parameter identification was also stud- ied. The results are in good agreement with finite element model, which validates the proposed method.
出处
《中国海洋大学学报(自然科学版)》
CAS
CSCD
北大核心
2016年第8期122-130,共9页
Periodical of Ocean University of China
基金
国家自然科学基金项目(51209189)
山东省优秀中青年科学家科研奖励基金项目(BS2012HZ023)
中央高校基本科研业务费青年教师科研基金项目(201213003)资助~~
关键词
海上风电结构
模态参数识别
环境激励
自然激励法
多参考点复指数法
offshore wind turbine
modal parameter identification
ambient excitation
Natural Excita- tion Technique (NEXT)
polyreference complex exponential (PRCE) method