环境激励下高桩码头模态参数识别及损伤诊断

Modal identification and damage diagnosis of the high-piled wharf under ambient excitation

高桩码头在长期使用过程中结构损伤是普遍存在的问题,有效检测结构损伤特别是隐蔽性部位对保证码头安全运营具有重要作用。利用NExT-ERA模态参数识别算法和模态应变能损伤定位原理,编制模态参数识别和损伤诊断程序。通过数值算例分析,验证环境激励下高桩码头排架基于模态参数识别及模态应变能进行损伤诊断的可行性和准确性。研究结果表明:NExT-ERA模态识别方法能较精确识别出高桩码头排架的动力参数;模态应变能变化率作为损伤诊断指标对损伤单元有较强的敏感性,能够识别出高桩码头不同工况下的损伤。

Structural damage is a common problem existing in high-piled wharfs during the long-term use, thus the efficient detection of visible and hidden structural damages is the key to guarantee the security operations of wharfs. In this study, the NExT-ERA modal i- dentification algorithm and modal strain energy damage location principle are investigated, and the procedures for modal parameters i- dentification and damage diagnosis are programmed. The damage diagnosis of high-piled wharfs under ambient excitation based on mo- dal parameters identification and modal strain energy is proved to be feasible and accurate through numerical analysis. The results show that NExT-ERA modal identification method can identify dynamic parameters of the high-pile pier bent accurately. The results also demonstrate that modal strain energy as damage diagnosis parameter is very sensitive to damage element and can identify the high-piled wharf damages under different operating conditions. The research results would provide a useful reference for non-destructive dynamic testing based on the dynamic characteristics of high-pile wharfs.