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Proceedings Paper

Lock-in thermographic methodology for fatigue assessment and nonlinear stress measurement
Author(s): Xiaogang Wang; Vincenzo Crupi; Yanguang Zhao; Xinglin Guo
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Paper Abstract

This scientific paper presents two approaches, based on the thermographic technique, for fatigue assessment and stress measurement. The first method, based on the lock-in thermography, is an energy approach; it takes intrinsic dissipation as the fatigue indicator, and evaluates the fatigue limit through a drastic change in the rate of dissipated energy. The second method is the Thermographic Method, which takes temperature increment as the fatigue indicator to assess the fatigue limit of materials and mechanical components. The Energy Approach of the Thermographic Method is based on the energy expression of linear fatigue cumulative damage hypothesis and allows the rapid assessment of the whole S-N curve. This research paper advances this quantitative thermographic method for residual fatigue life assessment. A stress analysis technique, known as SPATE (Stress Pattern Analysis by Thermal Emissions), measures the temperature variation due to the thermoelastic effect for stress determination, which could be unfaithful when the stress level is relatively high. Thus we proposed to use the Thermographic Method to assess the cyclic stress amplitude σa through the S-N curve. Good predictions were achieved using all the methods.

Paper Details

Date Published: 25 August 2009
PDF: 6 pages
Proc. SPIE 7375, ICEM 2008: International Conference on Experimental Mechanics 2008, 73752P (25 August 2009); doi: 10.1117/12.839226
Show Author Affiliations
Xiaogang Wang, Dalian Univ. of Technology (China)
Vincenzo Crupi, Univ. of Messina (Italy)
Yanguang Zhao, Dalian Univ. of Technology (China)
Xinglin Guo, Dalian Univ. of Technology (China)


Published in SPIE Proceedings Vol. 7375:
ICEM 2008: International Conference on Experimental Mechanics 2008
Xiaoyuan He; Huimin Xie; YiLan Kang, Editor(s)

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