Development and validation of advanced processing methods for enhancement of damage detectability in structures using shearography

• Dates: 2020-2021
• Place: University of Lisbon
• PI: Andrzej Katunin
• Cooperating staff: Jose Viriato Araújo dos Santos, Hernâni Miguel Reis Lopes
• Funding source: Polish National Agency for Academic Exchange

Among the variety of NDT methods available for structural testing a group of optical NDT methods is distinguished, since, in general, optical methods provide a possibility of fast, full-field, and non-contact structural testing with much higher spatial resolution with respect to other NDT methods, like ultrasonic testing or thermography. One of the most effective methods from the group of optical NDT methods is shearography, the method based on shearing of captured images, which makes it possible to detect, localize and identify a flaw based on disturbances of the interferometric fringes resulting from shearing the sets of captured images. The shearography provides an interferometric image, which is then subjected to the analysis by an operator to detect possible flaws based on observed disturbances in the interferometric fringes. The research was focused on detection of small damage sites which cannot be detected by the classical shearography as well as determination locations of these damage sites and identification of their shapes using advanced post-processing algorithms developed for this purpose.

Representative publications:

Katunin A., Araújo dos Santos J.V., Lopes H., Damage identification by wavelet analysis of modal rotation differences, Structures 30, 2021, 1-10.

Katunin A., Performance of damage identification based on directional wavelet transforms and entopic weights using experimental shearographic testing results, Sensors 21(3), 2021, 714.

Katunin A., Damage identification and quantification in beams using Wigner-Ville distribution, Sensors 20(22), 2020, 6638.

Araújo dos Santos J.V., Katunin A., Lopes H., Vibration-based damage identification using wavelet transform and a numerical model of shearography, International Journal of Structural Stability and Dynamics 19(4), 2019, 1950038.

Katunin A., Lopes H., Araújo dos Santos J.V., Identification of multiple damage using modal rotation obtained with shearography and undecimated wavelet transform, Mechanical Systems and Signal Processing 116, 2019, 725-740.