On the anelasticity and fatigue fracture entropy in high-cycle metal fatigue

Liakat, M.; Khonsari, M. M.

doi:10.1016/j.matdes.2015.04.034

Cited by 58 publications

(29 citation statements)

References 37 publications

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“…Their results pertain to fully reversed loading of un‐notched specimens. The concept of the FFE has also been used in high‐cycle fatigue (HCF) of metals as well as in presence of stress concentration …”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic entropy generation in the course of the fatigue crack initiation

Ontiveros

Amiri

Kahirdeh

et al. 2016

Fatigue Fract Eng Mat Struct

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Evolution of the thermodynamic entropy generation during fatigue crack initiation life of notched specimens is studied. A set of experimental results of AA7075‐T651 is examined to determine applicability of the thermodynamic entropy generation as an index of fatigue crack initiation. Entropy accumulation is calculated from hysteresis energy and temperature rise. An increasing trend of entropy accumulation with the number of cycle to failure is observed on macroscale measurements. Results also determine that the entropy generations from the samples under the same operating conditions are similar as the crack grows. Scanning electron microscope analysis is performed on the fractured surfaces to observe the fatigue striations, and persistent slip bands are observed employing an optical microscope. A discussion is presented regarding the length scales on which crack initiation occurs and entropy calculation is made.

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Section: Introductionmentioning

confidence: 99%

“…Their results pertain to fully reversed loading of un-notched specimens. The concept of the FFE has also been used in high-cycle fatigue (HCF) of metals 20 as well as in presence of stress concentration. 3 Fatigue failure assessment based on hysteresis energy and thermal response [21][22][23][24] has been under extensive study during past decades.…”

mentioning

confidence: 99%

Thermodynamic entropy generation in the course of the fatigue crack initiation

Ontiveros

Amiri

Kahirdeh

et al. 2016

Fatigue Fract Eng Mat Struct

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“…[35]). Processes of high-cycle fatigue, which are of great practical importance, are addressed in [43,44].…”

Section: Entropy In Fatigue Damage Processesmentioning

confidence: 99%

A Model of Mechanothermodynamic Entropy in Tribology

Sosnovskiy

Sherbakov

2017

Entropy

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A brief analysis of entropy concepts in continuum mechanics and thermodynamics is presented. The methods of accounting for friction, wear and fatigue processes in the calculation of the thermodynamic entropy are described. It is shown that these and other damage processes of solids are more adequately described by tribo-fatigue entropy. It was established that mechanothermodynamic entropy calculated as the sum of interacting thermodynamic and tribo-fatigue entropy components has the most general character. Examples of usage (application) of tribo-fatigue and mechanothermodynamic entropies for practical analysis of wear and fatigue processes are given.Keywords: entropy; mechanothermodynamics; tribo-fatigue; tribology; fatigue; damage Thermodynamic EntropyThe following functions are used to describe the state of thermodynamic systems [1]:where temperature T, volume V, and number of moles of chemical components N k are the macroscopic state variables. In the general case of an open system, the change dU of internal energy U is presented [1] as:where dQ is the amount of heat; dA is the amount of mechanical energy; dU sub is the amount of substance, which the system exchanged with the environment for a time interval dt; p is the pressure; the µ k 's are the chemical potentials. Planck especially emphasized that dU in Equation (2) is an infinitely small difference, whereas dQ, dA, and dU sub are the infinitely small amounts. It follows from (2) that entropy S change in a thermodynamic system (subscript T) is: Abstract: A brief analysis of entropy concepts in continuum mechanics and thermodynamics is presented. The methods of accounting for friction, wear and fatigue processes in the calculation of the thermodynamic entropy are described. It is shown that these and other damage processes of solids are more adequately described by tribo-fatigue entropy. It was established that mechanothermodynamic entropy calculated as the sum of interacting thermodynamic and tribofatigue entropy components has the most general character. Examples of usage (application) of tribo-fatigue and mechanothermodynamic entropies for practical analysis of wear and fatigue processes are given.

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“…Prediction of the fatigue life for both low-cycle fatigue (LCF) and high-cycle fatigue (HCF) is well developed based on the FFE as a material property (Jang and Khonsari, 2018; Liakat and Khonsari, 2014a, 2015a, 2015b; Naderi et al., 2010). However, the more challenging problem of predicting the remaining fatigue life (RFL) associated with fatigue still remains elusive.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive estimation of remaining fatigue life without the loading history

Jang

Mehdizadeh

Khonsari

2019

International Journal of Damage Mechanics

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A new nondestructive method to estimate the remaining fatigue life of a fatigue specimen with unknown knowledge of the loading history is presented. It requires only one short-time excitation test. The method utilizes the concept of damage parameter and the temperature rise to reliably predict the remaining number of cycles before fracture. A generalized procedure and numerous experimentally verified examples are presented. It is shown that the method can be applied to both constant and variable stress levels. Extensive laboratory tests reveal that the results of the remaining fatigue life predictions are in very good agreement with measurements.

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On the anelasticity and fatigue fracture entropy in high-cycle metal fatigue

Cited by 58 publications

References 37 publications

Thermodynamic entropy generation in the course of the fatigue crack initiation

Thermodynamic entropy generation in the course of the fatigue crack initiation

A Model of Mechanothermodynamic Entropy in Tribology

Nondestructive estimation of remaining fatigue life without the loading history

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