| Title |
Defect estimation in non-destructive testing of composites by ultrasonic guided waves and image processing / |
| Authors |
Tiwari, Kumar Anubhav ; Raisutis, Renaldas ; Tumsys, Olgirdas ; Ostreika, Armantas ; Jankauskas, Kestutis ; Jakutavicius, Julijus |
| DOI |
10.3390/electronics8030315 |
| Full Text |
|
| Is Part of |
Electronics.. Basel : MDPI. 2019, vol. 8, iss. 3, art. no. 315, p. 1-16.. ISSN 2079-9292 |
| Keywords [eng] |
defect ; composite ; image processing ; discrete wavelet transform ; nondestructive testing ; guided waves ; glass fiber-reinforced plastic |
| Abstract [eng] |
The estimation of the size and location of defects in multi-layered composite structures by ultrasonic non-destructive testing using guided waves has attracted the attention of researchers for the last few decades. Although extensive signal processing techniques are available, there are only a few studies available based on image processing of the ultrasonic B-scan image to extract the size and location of defects via the process of ultrasonic non-destructive testing. This work presents an image processing technique for ultrasonic B-scan images to improve the estimation of the location and size of disbond-type defects in glass fiber-reinforced plastic materials with 25-mm and 51-mm diameters. The sample is a segment of a wind turbine blade with a variable thickness ranging from 3 to 24 mm. The experiment is performed by using a low-frequency ultrasonic system and a pair of contact-type piezoceramic transducers kept apart by a 50-mm distance and embedded on a moving mechanical panel. The B-scan image acquired by the ultrasonic pitch-catch technique is denoised by utilizing features of two-dimensional discrete wavelet transform. Thereafter, the normalized pixel densities are compared along the scanned distance on the region of interest of the image, and a −3 dB threshold is applied to the locations and sizes the defects in the spatial domain. |
| Published |
Basel : MDPI |
| Type |
Journal article |
| Language |
English |
| Publication date |
2019 |
| CC license |
|
