Crack detection and characterization techniques - An overview

SUMMARY Crack occurrence and propagation are among critical factors that affect the performance and lifespan of civil infrastructures such as bridges, pipelines, and so on. As a consequence, numerous crack detection and characterization techniques have been researched and developed in the past decades in the areas of SHM and non-destructive evaluation (NDE). The significant amount of performed studies and the large number of publications give rise to the need to systematize, condensate, and summarize this enormous effort. The aims of this paper are to summarize the knowledge about cracking and its sources, review both existing and emerging methods for crack detection and characterization, and identify the advantages and challenges for these methods. In general, this paper identifies two sensing approaches (direct and indirect) and two data analysis approaches (model-based and model-free or data-driven) along with a range of associated technologies. The advantages and challenges of each approach and technology are discussed and summarized, and the future research needs are identified. This paper is intended to serve as a reference for researchers who are interested in crack detection and characterization as well as for those who are generally interested in SHM and NDE.