数字图像相关技术在结构损伤检测中的应用

Application of Digital Image Correlation Technology in Structural Damage Detection

结构损伤识别技术是结构健康监测的核心技术,也是健康监测的重难点之一。工程测量中受测量环境和技术的影响,很难获得完备的实验数据。论文利用一种新型测量技术,数字图像相关性(Digital Image Correlation,以下简称"DIC")技术,来提高模态应变能的识别精度。首先运用DIC技术和传统加速度传感器两种测量手段来获取固有频率和模态振型,实验结果表明,DIC技术获取的频率和振型与加速度传感器基本一致;随后对网壳结构进行基于DIC的模态应变能损伤识别分析,参数识别法获得模态振型及利用振型拟合得到的转角代入损伤识别指标进行损伤识别,结果表明,基于DIC的模态应变能损伤识别法能够有效进行损伤定位识别,且识别精度较好。

Structural damage identification technology is the core technology of structural health monitoring and one of the difficulty of health monitoring.Engineering measuring is affected by the measuring environment and technology,it is hard to obtain complete experimental data.This paper used digital image correlation technology,a new measuring technique to improve the identification accuracy of modal strain energy.Firstly,DIC technology and traditional acceleration sensors were used to obtain the natural frequency and frequency response function of reticulated shell structure.Experimental results showed that the acquired frequencies and mode shapes by means of DIC technology are basically the same as those obtained by the acceleration sensors.Then the damage identification analysis of the modal strain energy based on DIC was applied on a reticulated shell structure.Through the excitation and response signals,the frequency response function of the structure was obtained.Then the modal shape can be obtained by the parameter identification method.Finally,we used the damage index to identify the damage.The experimental results showed that the modal strain energy damage identification method based on DIC can effectively and fairly accurately identify the damage location.