Application of a New, Energy-Based ΔS* Crack Driving Force for Fatigue Crack Growth Rate Description

Abstract

This paper presents the problem of the description of fatigue cracking development in metallic constructional materials. Fatigue crack growth models (mostly empirical) are usually constructed using a stress intensity factor ΔK in linear-elastic fracture mechanics. Contrary to the kinetic fatigue fracture diagrams (KFFDs) based on stress intensity factor K, new energy KFFDs show no sensitivity to mean stress effect expressed by the stress ratio R. However, in the literature there is a lack of analytical description and interpretation of this parameter in order to promote this approach in engineering practice. Therefore, based on a dimensional analysis approach, ΔH is replaced by elastic-plastic fracture mechanics parameter—the ΔJ-integral range. In this case, the invariance from stress is not clear. Hence, the main goal of this paper is the application of the new averaged (geometrically) strain energy density parameter ΔS* based on the relationship of the maximal value of J integral and its range ΔJ. The usefulness and invariance of this parameter have been confirmed for three different metallic materials, 10HNAP, 18G2A, and 19th century puddle iron from the Eiffel bridge.

Advanced Simulation Tools Applied to Materials Development and Design Predictions

“…Normally, fatigue crack growth relations are usually presented by using a linear-elastic stress intensity factor range, ∆K. Lesiuk [14], from the Wroclaw University of Science and Technology, has been proposed a new energy-based crack driving force for the description of the fatigue crack growth rates.…”

Probabilistic strain-fatigue life performance based on stochastic analysis of structural and WAAM-stainless steels

“…It is important to compare the probabilistic fatigue behavior of WAAM steels with structural steels, such as S355 and S690, to provide an initial impression for the designer during replacing traditional structural steel with WAAM plates. Besides, the fatigue crack growth rates (FCGR) modelling based on the J-integral [37], stress intensity factor [38], equivalent initial flaw size (EIFS) [39], and energy-based ΔS* crack driving force [40] approaches, and considering some factors such as the crack closure effects [41], variable amplitude loading [42], and mixed-mode loading conditions [38], can also be supported by probabilistic analysis, as suggested in some researches [10,22,23,24,43,44].…”

Fatigue Crack Growth Rate in Long Term Operated 19th Century Puddle Iron

“…This bridge is located in Viana do Castelo, Portugal, crossing the Lima River, having a total length of 645 m. Another part of an ancient iron member was extracted from the restored viaduct (1863) located in Brochocin (Low Silesia, Poland),. Due to limited knowledge of the fatigue crack growth behaviour [3], this paper fills the gap in the literature on experimental results of fatigue crack growth (FCG) behaviour based on the effective stress intensity factor range and of a new parameter using the strain energy density concept for the metallic materials under consideration [4]. These FCG results are of great importance, since it allows the residual lifetime assessment of old metallic bridges of the same historical period, reducing the uncertainties associated with this type of materials.…”