基于振动响应相关性的简支梁桥损伤识别方法

On the damage identification method of simply-supported girder bridge based on vibration response correlation

针对已有的结构损伤识别方法需要已知结构损伤前的响应信息这种情况,尝试将提升小波变换与振动响应相关系数结合起来,提出一种不需要知道结构损伤前响应信息的简支梁桥结构损伤识别新方法。利用移动荷载激励作用下数值计算出的结构位移响应和经过提升小波变换处理后的位移响应,分别计算出相应的损伤指标,即位移响应相关系数曲率(Correlation Coefficient Curvature,CCC)。发现由提升小波变换处理后的位移响应计算出的损伤指标相对于直接利用位移响应计算出的损伤指标,损伤识别效果有很大提升,且基本不受车辆行驶速度的影响。通过对多种损伤工况下的简支梁桥的数值模拟和跨中损伤工况下的模型实验,证实了该损伤识别方法在结构损伤前响应信息未知的前提下,仍然具有可行性和有效性。

In view of the existing structural damage identification method needing to know the response information before structural damage,this .paper attempts to combine lifting wavelet transform with the correlation coefficient of vibration response and to propose a new method for structural damage identification of simply supported girder bridge without the need of knowing the response information before structural damage.The damage index (also known as corresponding correlation coefficient curvature,CCC)are calculated respectively using the numerical displacement response obtained under moving loads and the response transformed by lifting wavelet.It is found that the damage index calculated using the displacement response transformed by lifting wavelet can identify the damage position more accurately and less influenced by speed of vehicle,compared with damage index directly calculated using displacement response.The feasibility and validity of the proposed method which does not need the response of intact structure are verified by numerical examples under different damage conditions and experiments of simply-supported girder bridge.