海洋平台结构环境激励的实验模态分析

介绍了对位于渤海湾的“埕岛二号”中心生活平台所进行的现场测试实验,该平台为直立式导管架钢结构平台。此次现场实验是在波浪力、风等环境载荷激励下测试结构动力响应的。利用频域的模态识别法峰值法(PP)和时域中的自然激励法(NExT)结合特征系统实现算法(ERA)分别对海洋平台结构现场测试的动力响应数据进行模态参数识别;利用ANSYS建立了该平台结构的三维有限元模型,并进行结构的模态分析。海洋平台结构的理论和实验模态分析结果吻合较好,分析结果表明该类模态参数识别方法能够为结构损伤诊断提供基准模型,可以运用于实际结构的健康监测以及维护维修。

Experimental Modal Analysis of Offshore Platform under Operational Conditions

The field test of central platform "Chengdao No. 2" in Bohai bay, China is introduced. The platform is a steel jacket type offshore platform with vertical piles. The field test is carried out by conducting ambient vibration test under wave-induced force and wind force ect. The natural excitation technology(NExT) combined with eigensystem realization algorithm(ERA) and peak picking(PP) method in frequency domain is used for the output-only modal identification. The 3-D finite element model(FEM)is constructed by ANSYS and an analytical modal analysis is performed to generate modal parameters. The finite element model is validated to match the field test modal parameters of the offshore platform. According to the analysis results, the modal parameters identification method can serve as a baseline model for structural damage detection, structural health monitoring and maintenance of civel engineering structures.