Detection of localized fatigue damage in steel by thermography

Justus Medgenberg; Thomas Ummenhofer

doi:10.1117/12.720166

9 April 2007 Detection of localized fatigue damage in steel by thermography

Justus Medgenberg, Thomas Ummenhofer

Proceedings Volume 6541, Thermosense XXIX; 654117 (2007) https://doi.org/10.1117/12.720166
Event: Defense and Security Symposium, 2007, Orlando, Florida, United States

Abstract

Fatigue damage of unalloyed steels in the high cycle regime is governed by localized cyclic plastic deformations and subsequent crack initiation. The extent of early microplastic deformations depends on the applied stress level, stress concentration at macroscopic notches, surface treatment, residual stresses etc. The onset of a nonlinear material response can be regarded as an early indicator of fatigue damage. During fatigue loading thermoelastic coupling and thermoplastic dissipation cause characteristic temperature variations in tested specimens which have been assessed by a highly sensitive infrared camera. A specialized data processing method in the time domain has been developed which allows to separate the different contributions to the measured temperature signal. In contrast to other methods - as e.g. measuring the rise of mean temperature during fatigue loading - the proposed methodology is based on measurements during the stabilized temperature regimen and offers very high spatial resolution of localized phenomena. Investigations have been made on mildly notched cylindrical and also on welded specimens. The results confirm the close relation between the local temperature signal and typical fatigue phenomena. The new methodology allows for a much better localization and quantification of effects as cyclic plasticity, crack initiation, crack growth etc. The following paper presents considerations and experimental results of an application of thermography to the local assessment of fatigue damage.

Citation Download Citation

Justus Medgenberg and Thomas Ummenhofer "Detection of localized fatigue damage in steel by thermography", Proc. SPIE 6541, Thermosense XXIX, 654117 (9 April 2007); https://doi.org/10.1117/12.720166

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