Rapid evaluation of fatigue limit using energy dissipation

Abstract

Four different experimental approaches for rapid estimation of fatigue limit (endurance limit) based on energy dissipation during cyclic loading are discussed. The presented approaches use energy dissipation and thermography and can reliably evaluate the fatigue limit of material by conducting the fatigue test on a single specimen. Results show that the released energy due to damage accumulation at the stress levels above the fatigue limit changes the trend of energy dissipation and that this trend can be used to predict the fatigue limit. Experimental results on CS 1018 and SS 304 specimens are presented to illustrate the utility of the proposed methods.

On the Characteristics of Fatigue Fracture with Rapid Frequency Change

“…The effect of this non-damaging energy for stresses above the endurance limit must be accounted for in calculating the total accumulated entropy [47]. As shown in Figure 3, internal friction contributes to the slope of temperature evolution, and this contribution is considered a non-damaging source of heat generation [48]. Therefore, Equation ( 20) can be written to express the role of internal friction [18].…”

“…One side of the surface is painted black to increase the emissivity near to 1 for IR camera data acquisition purposes. As shown in Figure 3, internal friction contributes to the slope of temperature evolution, and this contribution is considered a non-damaging source of heat generation [48]. Therefore, Equation ( 20) can be written to express the role of internal friction [18].…”

Rapid Fatigue Limit Estimation of Metallic Materials Using Thermography-Based Approach

“…The essential point of the energy-based method is to construct a model so that one can connect the microstructural response with the irreversible dissipated energy. Numerous studies have been conducted for this aim throughout the years, many of which are compiled in the literature [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. In these models, Guo and his co-workers made a pioneering contribution to energy dissipation theory [25,35,38,39].…”

“…It is pointed out that energy dissipation consists of two components, namely anelastic dissipation and inelastic dissipation, wherein anelastic dissipation relates to non-damaging mechanical behaviors and inelastic dissipation corresponds to the damage accumulation during the fatigue process. More recently, Mahmoudi et al [41] determined the fatigue limit of the CS 1018 and SS 304 specimens by using the linear fitting of the energy dissipation vs. stress amplitude data. These studies provided a clear explanation of the link between energy dissipation and the mechanism of microstructural change.…”