Damage detection in rotating objects using position-triggered thermography

• Type: Article in International Scientific Journal
• Date: 2020

Authors

Sousa, PJ (Author) FEUP; Barros, F (Author) Other; Ramos, NV (Author) Other; Tavares, PJ (Author) Other; Moreira, PMGP (Author) Other

Journal

Title: Engineering Failure Analysis

Vol. 115

ISSN: 1350-6307

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 3 Citations

Other information

Authenticus ID: P-00S-8BN

DOI: 10.1016/j.engfailanal.2020.104642

Abstract (EN): Damage detection using non-destructive testing techniques is important to prevent damage in structures with long operating times. In the case of rotating structures with minimal downtime, such as wind turbines, it is advantageous to be able to detect these damages during operation. Thermography is a method that is capable of performing these measurements, but can still have some difficulties in field application. One such difficulty resides in the necessity of properly aligning each image with the previous ones to obtain difference thermograms with good quality. Thus, the present work proposes a method to properly align images by synchronizing the ter-mographic camera with the rotation of the object, using only external non-contact devices, all positioned on the same side of the specimen. In this case, a photodetector is used in a high -amplification mode, working like a single-pixel camera. It outputs a grey level signal that will vary when a blade passes in front of it. By detecting this change, it is possible to trigger the camera and/or a heat source in the correct angular position, and use the acquired images to obtain good quality thermograms. This approach was applied to defect detection in rotating carbon fibre blades from a 450-size RC helicopter. It was possible to obtain results in these dynamic experiments that were in agreement with the ones obtained in a static approach.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8