State of Volumetric Damage of Tribo-Fatigue System

Щербаков, С. С.

doi:10.1007/s11223-013-9444-3

Cited by 15 publications

(14 citation statements)

References 3 publications

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“…Finally, the damage is related to the discontinuity and integrity of a solid up to its decomposition e.g., into atoms (see Table 1) [46,47]. Thus, the damageability is treated as a fundamental property (and duty) of moving and deformable systems [4,[45][46][47], and the failure is considered as a specific type of damage, i.e., the corresponding discontinuity and integrity of objects including the ones of great practical importance [46][47][48][49][50][51][52].…”

Section: Tribo-fatigue Entropymentioning

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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Section: Tribo-fatigue Entropymentioning

confidence: 99%

A Model of Mechanothermodynamic Entropy in Tribology

Sosnovskiy

Sherbakov

2017

Entropy

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“…According to [82][83][84][85][86][87][88][89][90][91][92][93][94][95], the parameter u 0 will be interpreted as the initial activation energy of the disintegration process. It is shown that the quantity u 0 approximately corresponds both to the sublimation heat for metals and crystals with ionic bonds and to the activation energy of thermal destruction for polymers:…”

Section: Energy Theory Of Damage and Limiting Statesmentioning

confidence: 99%

“…The methods for calculation of dangerous volumes V ij for friction pairs and tribo-fatigue systems are developed similar to (59): ( 64) and outlined in [4,[90][91][92]. Here σ pV, Wq lim is the limiting stress based on the assigned criterion of damage and fracture.…”

Section: Energy Theory Of Damage and Limiting Statesmentioning

confidence: 99%

Mechanothermodynamic Entropy and Analysis of Damage State of Complex Systems

Sosnovskiy¹,

Sherbakov

2016

Entropy

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Abstract:Mechanics from its side and thermodynamics from its side consider evolution of complex systems, including the Universe. Created classical thermodynamic theory of evolution has one important drawback since it predicts an inevitable heat death of the Universe which is unlikely to take place according to the modern perceptions. The attempts to create a generalized theory of evolution in mechanics were unsuccessful since mechanical equations do not discriminate between future and past. It is natural that the union of mechanics and thermodynamics was difficult to realize since they are based on different methodology. We make an attempt to propose a generalized theory of evolution which is based on the concept of tribo-fatigue entropy. Essence of the proposed approach is that tribo-fatigue entropy is determined by the processes of damageability conditioned by thermodynamic and mechanical effects causing to the change of states of any systems. Law of entropy increase is formulated analytically in the general form. Mechanothermodynamical function is constructed for specific case of fatigue damage of materials due to variation of temperature from 3 K to 0.8 of melting temperature basing on the analysis of 136 experimental results.

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“…To construct integral characteristics of damage of the knife's material one uses the octahedral dangerous volume

V_{int} = \int_{ψ_{int} (V) \geq 1} d V,

the dangerous volume damage

Ψ_{int} = \int_{ψ_{int} (V) \geq 1} ψ_{int} ((), V) d V

whose general calculation methods are described in .…”

Section: Dangerous Volumesmentioning

confidence: 99%

“…whose general calculation methods are described in [4][5][6][7][8][9][35][36][37]. Values of the mentioned characteristics were defined for triangular elements of the computational grid presented in Fig.…”

Section: Dangerous Volumesmentioning

confidence: 99%

Modeling of volumetric damage of multielement clamp‐knife‐base tribo‐fatigue system

2016

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A multielement clamp‐knife‐base tribo‐fatigue system is considered. This system is the main part of a harvester's cutting instrument. Boundary element approach in indirect statement is used to model boundary conditions for system's elements taking into account contact interaction between them, cutting force applied to the knife and fixings. Stress‐strain state of the system is calculated as superposition of solutions for each boundary element to which predetermined surfaces tractions are applied. Damage state of each element of the system is calculated using the model of a solid with dangerous volume. According to this model dangerous volume is a set of elementary volumes in which acting stresses (strains) are greater than the limiting stress (strain). Obtained results show that the choice of material of the knife (steel or high strength cast iron) and the value of cutting force has significant effect on system's stress‐strain state and state of damage.

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State of Volumetric Damage of Tribo-Fatigue System

Cited by 15 publications

References 3 publications

A Model of Mechanothermodynamic Entropy in Tribology

A Model of Mechanothermodynamic Entropy in Tribology

Mechanothermodynamic Entropy and Analysis of Damage State of Complex Systems

Modeling of volumetric damage of multielement clamp‐knife‐base tribo‐fatigue system

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