环境激励下结构损伤识别的综合指标法试验研究

EXPERIMENTAL INVESTIGATION OF STRUCTURAL DAMAGE IDENTIFICATION BY COMBINATION INDEX METHOD UNDER AMBIENT EXCITATION

结构损伤识别是结构健康监测和结构状态评估的主要前提之一。尽早了解结构的损伤状况和损伤位置有助于提高结构的预期可靠性和安全性,同时降低了结构的维修费用。论文主要研究了如何在环境激励下识别结构的损伤状况。基于曲率模态对结构局部损伤比较敏感和频率指标测试简单方便、精度高的特点,提出了一种以结构的曲率模态为基础,综合考虑频率变化的改进结构损伤识别方法。为了能够在不影响结构运营的前提下对其进行损伤识别,随机子空间方法被引入到该改进的结构损伤识别方法中,最后用一简支混凝土梁对该方法进行了试验验证。试验结果表明:改进的结构损伤识别方法结合随机子空间方法能够有效地识别环境激励下的结构损伤,避免了对结构运营的影响。

Structural damage identification is one of the major prerequisites of structural health monitoring and structural status assessment.Early detection of the damage and its location can help improving the reliability and safety of the structure,thus reducing the maintenance cost.The paper focuses on how to identify the structural damage under ambient excitation.Since the curvature mode is more sensitive to structural local damage,while the frequency is easy to test with high precision,the paper presents an improved structural damage identification method based on structural curvature mode and the frequency change.In order to identify the structural damage under ambient excitation without interrupting its structural operation,stochastic subspace identification is introduced in the method.Finally,a simple support concrete beam is then tested in the laboratory to verify the effectiveness of the structural damage identification method presented herein.The test results show that the improved method with stochastic subspace identification can effectively identify the structural damage under ambient excitation without interrupting the operation of structure.