基于模态柔度的高桩码头损伤识别方法研究

Damage Identification Method of High⁃piled Wharf Based on Modal Flexibility

高桩码头在长期服役后,其健康状态及安全性受到学者们的广泛关注。高效、快捷、准确地对现役高桩码头的损伤状态和损伤位置进行识别对码头的维护与健康监测具有重要意义。以某高桩码头基桩为研究对象,对含有三榀排架的码头结构段进行数值模拟,设置4种不同损伤程度和多位置损伤的工况,研究了基于码头损伤前后模态柔度的基桩损伤识别方法。提出了2类损伤指标:模态柔度差和模态柔度差曲率。研究表明,提出的两类损伤指标能够有效表征出高桩码头基桩不同程度的损伤,但是,多损伤工况下的损伤识别效果弱于单损伤工况;二阶模态下的损伤指标的识别效果普遍优于一阶模态;基于模态柔度差曲率的损伤指标的损伤位置信号明显,具有较高的防误判性。

The health status and safety of high⁃pile wharves after long⁃term service have been widely discussed by scholars.Therefore,the efficient,quick and accurate identification of the damage state and damage location of the existing high⁃pile wharf is of great significance for the maintenance and health monitoring of the wharf.Taking the foundation pile of a high⁃pile wharf as the research object,finite element technology was used to simulate the wharf structure section with three pieces of bent frames.Four different damage degrees and multi⁃position damage conditions were set up,and the damage identification method of foundation piles based on modal flexibility before and after wharf damage was studied.Two kinds of damage indexes were proposed,modal flexibility difference and modal flexibility difference curvature.The results show that the two types of damage indexes proposed can effectively characterize the different degrees of damage to piles in high⁃pile wharves.However,the damage identification effect under multi⁃damage conditions is weaker than that under single⁃damage conditions.The identification effect of the damage index under the second⁃order mode is generally better than that of the first⁃order mode;the damage location signal of the damage index based on modal flexibility difference curvature is obvious,which has high anti⁃misjudgment.