Hardness measurements as a technique for measuring accumulated fatigue damage

Abstract

PurposeBrinell, Vickers and low-force Vickers hardness measurements are herein adopted to investigate and quantify the fatigue damage evolution in specimens made of S355J2+AR ferritic pearlitic steel. Though nano and microhardness measurements have been well adopted, they require a strict preparation routine, whereas macroscopic hardness measurements are not as stringent.Design/methodology/approachThe feasibility of adopting macroscopic hardness measurements as a means of measuring fatigue damage is investigated through a combination of experimental tests and finite element analyses with both Brinell and Vickers hardness indenter.FindingsIt is found that the Brinell hardness measurements method seems more feasible, regarding finding a continuous and significant change during the fatigue life, in comparison to both Vickers and low-force Vickers. Thereafter, the question regarding the feasibility of the hardness measurements as a method of assessing accumulated fatigue damage in situ is discussed.Originality/valueMuch work has previously been performed towards correlation of the micro and nano hardness indentations, which generally has stringent preparation requirements before testing. Herein, the adoption of macroscopic hardness measurements as a means of assessing accumulated fatigue damage is considered both experimentally and theoretically.

Cumulative fatigue damage theories for metals: review and prospects

“…Considering the complexity of fatigue damage cumulation concerning the loading path, the isodamage lines in Subrahmanyan's model (Subramanyan, 1976; Bjørheim et al ., 2022a, b, c) are defined by two extreme lines. Specifically, one is the S–N curve of the material, which represents the total fatigue damage state (100%) of the specimen/component of interest; the other is the horizontal line through the fatigue limit of the material, which represents the initial or zero fatigue damage state of the specimen/component.…”

“…A new nonlinear fatigue damage accumulation model is proposed in light of the theory of the S–N fatigue damage envelope, proposed by Pavlou (Bjørheim et al ., 2022a, b, c; Pavlou, 2018, 2022).…”

Studies on structural heterogeneity of high-strength sheet materials

“…[1]-[5] є достатньо простими, швидкими, чутливими та універсальними методами дослідження механічних властивостей різноманітних матеріалів, які не потребують виготовлення спеціальних зразків та еталонів. Отримати кількісну характеристику стану металу можна за допомогою методу LM -твердості [6]-[8], згідно з яким в якості інформаційних ознак стану металу приймаються не абсолютні значення будь якої механічної характеристики, а параметри розсіювання її значень при масових вимірах.…”