摘要
Automatic detection and assessment of surface cracks are beneficial for understanding the mechanical performance of ultra-high performance concrete(UHPC).This study detects crack evolution using a novel dynamic mode decomposition(DMD)method.In this method,the sparse matrix‘determined’from images is used to reconstruct the foreground that contains cracks,and the global threshold method is adopted to extract the crack patterns.The application of the DMD method to the three-point bending test demonstrates the efficiency in inspecting cracks with high accuracy.Accordingly,the geometric features,including the area and its projection in two major directions,are evaluated over time.The relationship between the geometric properties of cracks and load-displacement curves of UHPC is discussed.Due to the irregular shape of cracks in the spatial domain,the cracks are then transformed into the Fourier domain to assess their development.Results indicate that crack patterns in the Fourier domain exhibit a distinct concentration around a central position.Moreover,the power spectral density of cracks exhibits an increasing trend over time.The investigation into crack evolution in both the spatial and Fourier domains contributes significantly to elucidating the mechanical behavior of UHPC.
基金
The first author would like to acknowledge the support from 2022 Open Project of Failure Mechanics and Engineering Disaster Prevention,Key Laboratory of Sichuan Province,No.FMEDP202204
The authors acknowledge the financial support from the National Natural Science Foundation of China(Grant Nos.52108379 and 51908504)
Youth Top Talent Program,Education Department of Hebei Province(No.BJK2022047)
Natural Science Foundation of Hebei Province(No.E2021210002)
Scientific Research Foundation for the Returned Overseas Scholars,Hebei Province(No.C20210307)
Innovation Research Group Program of Natural Science,Hebei Province(No.E2021210099).