Issue 51

A. Vedernikova et alii, Frattura ed Integrità Strutturale, 21 (2020) 1-8; DOI: 10.3221/IGF-ESIS.51.01 1 Focussed on IGF25 – Fracture and Structural Integrity International Conference 2019 Three approaches to evaluate the heat dissipated during fatigue crack propagation experiments A. Vedernikova, A. Iziumova, A. Vshivkov, O. Plekhov Institute of Continuous Media Mechanics UB RAS, 614013 Perm, Russia terekhina.a@icmm.ru , https://orcid.org/0000-0003-1069-7887 fedorova@icmm.ru, https://orcid.org/0000-0002-1769-9175 vshivkov.a@icmm.ru, https://orcid.org/0000-0002-7667-455X poa@icmm.ru , https://orcid.org/0000-0002-0378-8249 A BSTRACT . This work is devoted to the comparative analysis of three techniques for measurement of energy dissipation in metals under fatigue crack propagation: use of original contact heat flux sensor, post-processing of infrared thermography data and lock-in thermography. Contact heat flux sensors allow real-time recording of heat source values. Non-contact temperature measurements by infrared thermography techniques make it possible to calculate the heat source field on the specimen surface by solving a heat conductivity equation. Lock-in thermography is a well-established technique for measuring energy dissipation under cyclic loading conditions based on the analysis of the second harmonic amplitude of the thermal signal. This paper describes the results of the experiments with V-notched flat specimens made of stainless steel AISI 304 which were subjected to cyclic loading. It was shown that the values of energy dissipation estimated by different techniques are in good qualitative agreement. Contact and non- contact measurements can be used for investigation of energy dissipation either separately or in combination. Based on the measurements, the power dependence of fatigue crack growth rate on dissipated heat near the crack tip can be obtained. K EYWORDS . IR-thermography; Lock-in thermography; Heat flux sensor; Dissipated energy; Fatigue crack propagation. Citation: Vedernikova, A., Iziumova, A., Vshivkov, A., Plekhov, O., Three approaches to evaluate the heat dissipated during fatigue crack propagation experiments, Frattura ed Integrità Strutturale, 51 (2020) 1-8. Received: 27.08.2019 Accepted: 08.10.2019 Published: 01.01.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ne of the key problems of fracture mechanics and strength analysis is to predict the fatigue life of cracked parts of engineering constructions subjected to cyclic loading. The fatigue crack growth well correlates with energy dissipation at the crack tip [1-25]. Different experimental approaches focused on the experimental study of the dissipated energy are described in the literature. O