Comparison of lock-in and pulse-phase thermography for defect characterization in FRP composites applied to concrete

Jeff Brown; Sai Harsha Chittineni

doi:10.1117/12.2177260

12 May 2015 Comparison of lock-in and pulse-phase thermography for defect characterization in FRP composites applied to concrete

Jeff Brown, Sai Harsha Chittineni

Author Affiliations +

Proceedings Volume 9485, Thermosense: Thermal Infrared Applications XXXVII; 94850B (2015) https://doi.org/10.1117/12.2177260
Event: SPIE Sensing Technology + Applications, 2015, Baltimore, MD, United States

Abstract

Thermal imaging is a well-established technique for the non-destructive evaluation of FRP composites applied to reinforced concrete. Defect characterization using IR thermography, however, remains a topic of on-going research, and there are currently no universally accepted standards for data collection or interpretation. This research involved large scale thermography inspection of two FRP strengthened bridge girders that were removed from service after approximately 10 years of service in a potentially corrosive marine environment. Trial inspections were performed on test areas where defects could be identified using sounding methods. Two procedures showed the most promise for identifying and characterizing defects: sinusoidal (lock-in style) heating with periods ranging from 5 s to 40 s and constant step heating for 30 s followed by 60 s of cooling. Both methods resulted in a series of phase images that provided insight into the depth and general nature of detected defects. This paper presents the findings of a comparison study between these two thermal imaging techniques.

Citation Download Citation

Jeff Brown and Sai Harsha Chittineni "Comparison of lock-in and pulse-phase thermography for defect characterization in FRP composites applied to concrete", Proc. SPIE 9485, Thermosense: Thermal Infrared Applications XXXVII, 94850B (12 May 2015); https://doi.org/10.1117/12.2177260

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available