A design of multi-mode excitation source for optical thermography nondestructive sensing

Zhu, Yuyu, Gao, Bin, Wu, Shichun, Zhang, Yangzhen, Wang, Meiling, Woo, Wai Lok and Liao, Yongbo (2018) A design of multi-mode excitation source for optical thermography nondestructive sensing. Infrared Physics & Technology, 94. pp. 23-31. ISSN 1350-4495

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Abstract

Optical thermography is an important non-destructive testing (NDT) method which has been widely used in the fields of modern aerospace, renewable energy, nuclear industry, etc. The excitation source is a crucial device for the optical thermography system whose performance has a decisive effect on the detection results. Previous thermography NDT studies mainly focused on the physical mechanism, applications and signal processing algorithms. However, the design of the excitation source is rarely discussed. Due to the wide frequency range as well as the high power excitation requirements, it is a challenging task to develop a multi-mode excitation source for thermography NDT. This paper presents a novel design of the excitation source with a structure topology that combines the circuit with low frequency sinusoidal generation and a chopper circuit. It intimately satisfies the requirements of multiple-mode excitation for optical thermography. These include pulsed thermography (PT), lock-in thermography (LT), step heating thermography (ST), pulsed phase thermography (PPT), frequency modulated thermal wave imaging (FMTWI) and barker coded thermal wave imaging (BCTWI). The proposed topology, operating principle and the design procedure of the circuit have been investigated in details. A 2 kW prototype with a frequency range of 0.01 Hz–100 kHz has also been implemented. Validation of the proposed method has been undertaken to detect inner defects of both on a composite sample and a lead-steel sample with bonded structure.

Item Type:	Article
Uncontrolled Keywords:	Excitation source, Non-destructive testing, Optical thermography
Subjects:	H600 Electronic and Electrical Engineering
Department:	Faculties > Engineering and Environment > Computer and Information Sciences
Depositing User:	Paul Burns
Date Deposited:	22 Mar 2019 17:49
Last Modified:	10 Oct 2019 21:15
URI:	http://nrl.northumbria.ac.uk/id/eprint/38508

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