Structural Damage Localization With Distributed Strain Monitoring

Major and complex civil engineering structures, such as offshore platforms, subsea pipelines, large-span bridges, large steel structure carries important functions and safety requirements. Operating and maintaining them have to face the problems that they has a large volume and space, with complex loads and hard to monitor. Traditional means of monitoring are difficult to complete their long-term monitoring task. Distributed fiber optic monitoring technology breakthrough the bottleneck of traditional surveillance, and provides us with a easy and effective method for temperature and strain monitoring. In this paper, we attempt to identify the crack location by using the distributed strain data, it can provides a foundation for this technology applied in the large and complex structures.First, we introduce the development of distributed fiber optic monitoring technology, and make a detailed analysis of the principles and characteristics of Brillouin scattering optical fiber technology, in addition, we discuss the relationship between techniques of BOTDA and temperature and strain, the study of the relationship between them carry out showing a good linearity. We theoretically study and deduced the structural damage monitoring in the way of using BOTDA technology. And carry out the relevant numerical simulation and experiment.We designed a model test, by pre-crack in the steel beam to simulate the structural damage. We monitor the whole process of the crack changes. By simulating the damage of steel beam we study the crack detection performance of BOTDA fiber sensor in the single injury and multiple injuries. The results show that the BOTDA fiber optic sensors can accurately and effectively identify the location of cracks in steel beams, and achieve distributed damage monitoring of complex structures.