Crack localization on a statically deflected beam by high-resolution photos

Crack localization on a statically deflected beam by high-resolution photos

Andrea Vincenzo De Nunzio, Giada Faraco

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Abstract. In a context where the complexity of systems and their interconnection is increasing exponentially, the possibility of being able to monitor the structural integrity of crucial parts of structures is of considerable importance. In addition, the availability of modern and advanced tools opens the door to the advent of new diagnostic techniques. In this regard, the authors here deeply investigate and test a modern technique that allows to analyze a structure starting from a photo in order to identify and locate damage present in the structure in a rapid and non-destructive way. This allows to obtain an accurate location of the damage and consequently a quick evaluation of its state of integrity. Moreover, a further advantage lies in the possibility of carrying out the analysis in a non-invasive way without any physical interaction with the analyzed structure. The suitability of the technique is tested on a statically deformed beam in epoxy glass laminate. It has a notch, which represents the defect, and the goal is to determine the notch position, which is not visible in the photo. The basis of the proposed method is the correlation between the curvature that the beam presents under load conditions and its flexural stiffness. The damage on the beam, in fact, leads to a punctual alteration of its flexibility which is identified by sudden changes in the second derivative of the transversal deflection. The proposed methodology consists in taking a photo of the inflected beam; subsequently, the acquired photo is manipulated with specifically designed image processing tools, first to segment the beam shape and then to extract its axis. Finally, the second derivative is extracted using two different numerical differentiator filters (Lanczos filters and Gaussian wavelets) along with suitable processing to reduce the border distortions. The tests conducted demonstrate that it is possible to accurately detect the position of the notch. Although the authors realize that the technique can generally need sensibly large displacements, the results seem promising. Such a need is probably due to the resolution of the camera, which can sometimes represent a technological limit. It is believed that higher resolution would allow damage to be detected even for smaller displacements. A fundamental advantage is the speed of the methodology illustrated since it takes just a few moments from taking the photo to evaluating the results. This is accompanied by the ease of acquiring the measurement, which involves the use of the camera and its support without additional equipment.

Structural Health Monitoring, Crack Detection, Image Processing, Optical Measurements

Published online 11/1/2023, 5 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: Andrea Vincenzo De Nunzio, Giada Faraco, Crack localization on a statically deflected beam by high-resolution photos, Materials Research Proceedings, Vol. 37, pp 308-312, 2023


The article was published as article 67 of the book Aeronautics and Astronautics

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

[1] H.-N. Li, L. Ren, Z.-G. Jia, T.-H. Yi, D.-S. Li, State-of-the-art in structural health monitoring of large and complex civil infrastructures, J Civil Struct Health Monit. 6 (2016) 3–16.
[2] C.-Z. Dong, F.N. Catbas, A review of computer vision–based structural health monitoring at local and global levels, Structural Health Monitoring. 20 (2021) 692–743.
[3] D. Feng, M.Q. Feng, Computer vision for SHM of civil infrastructure: From dynamic response measurement to damage detection – A review, Engineering Structures. 156 (2018) 105–117.
[4] Z. Dworakowski, P. Kohut, A. Gallina, K. Holak, T. Uhl, Vision-based algorithms for damage detection and localization in structural health monitoring: Vision-based Algorithms for Damage Detection and Localization, Struct. Control Health Monit. 23 (2016) 35–50.
[5] J. Shi, X. Xu, J. Wang, G. Li, Beam damage detection using computer vision technology, Nondestructive Testing and Evaluation. 25 (2010) 189–204.
[6] R. Kumar, S.K. Singh, Crack detection near the ends of a beam using wavelet transform and high resolution beam deflection measurement, European Journal of Mechanics – A/Solids. 88 (2021) 104259.
[7] A.K. Pandey, M. Biswas, M.M. Samman, Damage detection from changes in curvature mode shapes, Journal of Sound and Vibration. 145 (1991) 321–332.
[8] U. Andreaus, P. Casini, Identification of multiple open and fatigue cracks in beam-like structures using wavelets on deflection signals, Continuum Mech. Thermodyn. 28 (2016) 361–378.
[9] B. Trentadue, A. Messina, N.I. Giannoccaro, Detecting damage through the processing of dynamic shapes measured by a PSD-triangular laser sensor, International Journal of Solids and Structures. 44 (2007) 5554–5575.
[10] A. Khaloo, D. Lattanzi, Pixel‐wise structural motion tracking from rectified repurposed videos, Struct Control Health Monit. 24 (2017).
[11] C. Lanczos, Applied Analysis (1956), Dover Publications, New York
[12] A. Messina, Detecting damage in beams through digital differentiator filters and continuous wavelet transforms, J. of Sound and Vib. 272(2004) 385-412.
[13] A. Messina, Refinements of damage detection methods based on wavelet analysis of dynamical shapes, International Journal of Solids and Structures. 45 (2008) 4068–4097.