基于曲率模态曲线变化的桥梁损伤识别

Bridge Damage Identification Based on Curvature-mode Curve

针对传统损伤识别方法仅能对损伤位置进行确定,对于损伤程度识别效果较差的问题,根据桥梁出现损伤会使曲率模态曲线产生畸变这一特点,提出一种基于曲率模态曲线变化的损伤识别方法。以曲率模态参数指标为基础,对桥梁损伤前后其曲率模态曲线的变化进行研究。采用多项式拟合和BP神经网络拟合技术,根据桥梁受损后其曲率模态曲线畸变面积的大小来反向拟合出现损伤的位置和损伤程度。以一座简支桥为例,对其设定单损伤和多损伤工况进行研究分析,根据曲率模态曲线畸变产生的部位确定结构损伤的位置,并根据曲率模态曲线的畸变大小来拟合桥梁损伤的程度。结果表明:对于实际工程中经常出现的小损伤工况,该方法识别效果较好,可用于实际工程结构的监测。

Aiming at the problem of traditional damage identification method which could only determine the damage position,and the damage degree recognition was poor,a damage identification method based on the change of curvature-mode was proposed in the light of the distortion of curvature-mode curve caused by bridge damage.Based on the parameter index of curvature mode,the change of curvature-mode curve of bridge before and after damage was studied.Based on polynomial fitting and neural network fitting technology,according to the size of curvature-mode curve distortion area after bridge damage,the location and degree of damage were reversely fitted.Taking a simply supported bridge as an example,the single and multi location damage conditions were studied and analyzed,and the location of structural damage was determined according to the location of curvature-mode curve distortion.The damage degree was determined by the size of curvature-mode curve distortion.The results show that the proposed method is more effective in identifying the small damage condition which is commonly seen in the actual engineering,and it can be used in the health monitoring of engineering structure.