Quantitative Thermometry: A Revived Simplified Approach to Fatigue Strength Determination and Deformation Mechanisms

Abstract

It has long been known that plastic deformation and fatigue damage lead to a heat generation im metals. In the past two decades, thermographic approaches have been improved by thermography and widely adapted to obtain an estimate for the fatigue strength from the change in temperature or the amount of heat generation. In this study, based on a 40-year-old, but rarely established measurement technique using NTC thermistors, the temperature profile on a specimen was gathered and assessed based on state-of-the-art evaluation strategies, e.g., also by using infrared camera technology. A direct comparison with thermographic measurement not only reveals the significantly higher resolution of this simple and inexpensive method. It also elucidated that in the transition from low to high heat generation, associated with a lower estimate for the fatigue strength, for some groups of materials the high resolution of the NTCs is necessary for a reliable determination.