Research on structural damage identification method based on optical flow method and flexibility difference

Dynamic fingerprints of structures such as dynamic displacements, vibration patterns and frequencies are important parameters for structural health monitoring. In this paper, a structural damage identification method based on spatio-temporal sequence images is proposed for the shortcomings of traditional structural health monitoring systems such as high cost, discontinuous measurement points and mismatch between sensor lifetime and the lifetime of the structure itself, which uses a camera to collect the vibration information of the structure and adopts the optical flow method for spatio-temporal sequence The method uses a camera to capture the structural vibration information, adopts the optical flow method to track the dynamic displacement of the structure in the images, obtains the full-domain displacement, vibration pattern and frequency of the structure, and uses Python to compile a flexibility difference calculation program to locate the structural damage according to the flexibility difference after the structural damage. The method was experimentally studied on a cantilever beam structure. The results show that the dynamic characteristics of the structure obtained by using the method in this paper match the results of the numerical simulation, and the maximum error of the structural frequency is 2. 9%. The damage location of the structure (unit 9) can be precisely located according to the flexibility difference after damage. The method has the advantages of being convenient efficient, full information, low cost and non-contact, while its accuracy is comparable to that of the theoretical method, providing a new means of obtaining holographic dynamic properties of structures and locating structural damage.