环境激励下自升式海洋平台损伤诊断

为探究适用于海洋平台结构的有效损伤诊断方法，针对某自升式平台的比例模型开展环境激励下损伤诊断试验研究。分别采用频域法中的增强频域分解法和时域法中的随机子空间法处理测试数据，提取前三阶的固有频率、振型和阻尼比等模态参数，并结合频率和振型识别结果计算节点柔度矩阵。通过分析平台模型模态参数和节点柔度矩阵的变化率，识别预先设置的结构损伤。试验结果表明，两种模态识别方法均能有效识别环境激励下的平台模型模态参数，其中利用固有频率变化率能够有效判断结构是否产生损伤，利用振型和柔度矩阵的变化率能够实现损伤的准确定位。

Damage Diagnosis of Jack-up Offshore Platform under the Environmental Motivation

In order to explore an effective damage diagnosis method for offshore platform structures, an experimental study on damage diagnosis under the environmental motivation was carried out for a proportional model of a jack-up platform. The test data are processed by the enhanced frequency domain decomposition method in frequency domain and the stochastic subspace identification method in time domain. The natural frequencies, mode shapes and damping ratios of the first three modes are extracted, and the nodal flexibility matrix is calculated by combining the identification results of frequency and mode shapes. By analyzing the change rate of modal parameters and nodal flexibility matrix of the platform model, the pre-set structural damage can be identified. The experimental results show that the two modal identification methods can effectively identify the modal parameters of the platform model under environmental motivation. The frequency identification results can effectively identify structural damage, and the change rate of mode and flexibility matrix can accurately locate the damage.