Loading…

Detecting deeper defects using pulse phase thermography

► Detectable defect depth depends on the phase image frequency. ► Analytical calculations were performed to evaluate the phase data. ► We reveal a mechanism to detect deeper defects in lower-frequency phase images. ► Optimum frequencies were determined for various defect depths and sizes. ► Detectab...

Full description

Saved in:
Bibliographic Details
Published in:Infrared physics & technology 2013-03, Vol.57, p.42-49
Main Authors: Ishikawa, Masashi, Hatta, Hiroshi, Habuka, Yoshio, Fukui, Ryo, Utsunomiya, Shin
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:► Detectable defect depth depends on the phase image frequency. ► Analytical calculations were performed to evaluate the phase data. ► We reveal a mechanism to detect deeper defects in lower-frequency phase images. ► Optimum frequencies were determined for various defect depths and sizes. ► Detectable depths of defects were improved by considering the optimum frequency. Detectable defect depth by pulse phase thermography (PPT) is reportedly improved when using phase at low frequency. This study was conducted to identify mechanisms detecting deeper defects by the PPT, and to determine the optimum frequencies for detecting defects with various depths and sizes. One-dimensional and finite element analyses reveal that the optimum frequency decreases continuously with increasing defect depth, and that the amplitude of noise appearing in phase data decreases with decreased frequency. These engender a large signal-to-noise ratio for deep defects in a lower-frequency range. The analytical results were verified by experiments for a polymethylmethacrylate specimen having artificial defects. The experimental results at the optimum frequency demonstrated that defects with up to 5–6mm depth were detected, which is a significant improvement compared with the reported detectable defect depth of 3.5mm.
ISSN:1350-4495
1879-0275
DOI:10.1016/j.infrared.2012.11.009