scholarly journals Influence of Chemical Heterogeneity and Third Body on Adhesive Strength: Experiment and Simulation

2021 ◽  
Vol 7 ◽  
Author(s):  
Iakov A. Lyashenko ◽  
Qiang Li ◽  
Valentin L. Popov
Keyword(s):  
Indentation Depth ◽  
Normal Force ◽  
Adhesive Contact ◽  
Chemical Heterogeneity ◽  
Third Body ◽  
The Third ◽  
Contact Configuration ◽  
Geometrical Shapes ◽  
Equal Radius ◽  
Sand Particles

We investigate experimentally and numerically the influence of chemical heterogeneity and of third-body particles on adhesive contact. Chemical heterogeneity is generated by chemical treatment of the contacting bodies changing locally the surface energy. For studying the influence of the third body, two types of particles are used: sand particles with various geometrical shapes and sizes, and steel spheres of equal radius. Dependencies of the normal force on the indentation depth at both indenting and pull-off as well as the evolution of the contact configuration are investigated. Corresponding numerical simulations are carried out using the boundary element method (BEM).

The role of the third body in the fretting wear of 690 alloy

2020 ◽  
Vol 34 (09) ◽  
pp. 2050077
Author(s):  
Xue Mi ◽  
Xiao-Ming Bai ◽  
Pan Tang ◽  
Hai Xie ◽  
Jin-Fang Peng ◽  
...  
Keyword(s):  
Room Temperature ◽  
Normal Force ◽  
Fretting Wear ◽  
Wear Particles ◽  
Third Body ◽  
Experimental Conditions ◽  
The Third ◽  
The Coefficient Of Friction ◽  
Friction Energy

In this work, to investigate the role of the third body in the fretting behavior of 690 alloy, the fretting capabilities of 690 alloy against 405 stainless steel have been performed under various experimental conditions. The testing normal force and temperature varied from 10 N to 40 N and from room-temperature (RT) to [Formula: see text]C, respectively, at 5 Hz and 200 [Formula: see text]m. The results demonstrated that the profile shape of wear scar was dependent on the action of the wear particles. Three typical profile shapes were examined in this work: “U” shape, “W” shape and “M” shape. The balance of the formation and ejection of wear particles led to a steady value of the coefficient of friction (COF) and friction energy.

scholarly journals Extended analytical formulae for the perturbed Keplerian motion under low-thrust acceleration and orbital perturbations

2021 ◽  
Vol 133 (3) ◽  
Author(s):  
Marilena Di Carlo ◽  
Simão da Graça Marto ◽  
Massimiliano Vasile
Keyword(s):  
Gravitational Perturbation ◽  
Low Thrust ◽  
Orbital Elements ◽  
Third Body ◽  
The Third ◽  
Orbital Perturbations ◽  
Analytical Formulae ◽  
Numerical Orbit ◽  
Body Potential

AbstractThis paper presents a collection of analytical formulae that can be used in the long-term propagation of the motion of a spacecraft subject to low-thrust acceleration and orbital perturbations. The paper considers accelerations due to: a low-thrust profile following an inverse square law, gravity perturbations due to the central body gravity field and the third-body gravitational perturbation. The analytical formulae are expressed in terms of non-singular equinoctial elements. The formulae for the third-body gravitational perturbation have been obtained starting from equations for the third-body potential already available in the literature. However, the final analytical formulae for the variation of the equinoctial orbital elements are a novel derivation. The results are validated, for different orbital regimes, using high-precision numerical orbit propagators.

The Effect of the Third Body on the Fretting Wear Behavior of Coatings

2002 ◽  
Vol 11 (3) ◽  
pp. 288-293 ◽  
Author(s):  
Gui-Zhen Xu ◽  
Jia-Jun Liu ◽  
Zhong-Rong Zhou
Keyword(s):  
Wear Behavior ◽  
Fretting Wear ◽  
Third Body ◽  
The Third

A mathematical model for the third-body concept

2017 ◽  
Vol 23 (3) ◽  
pp. 420-432 ◽  
Author(s):  
Pavel Krejčí ◽  
Adrien Petrov
Keyword(s):  
Mathematical Model ◽  
A Priori Estimates ◽  
A Priori ◽  
Dynamical Problem ◽  
Sobolev Embedding ◽  
Third Body ◽  
Embedding Theory ◽  
The Third ◽  
Galerkin Approximations ◽  
Body Concept

The third-body concept is a pragmatic tool used to understand the friction and wear of sliding materials. The wear particles play a crucial role in this approach and constitute the main part of the third-body. This paper aims to introduce a mathematical model for the motion of a third-body interface separating two surfaces in contact. This model is written in accordance with the formalism of hysteresis operators as solution operators of the underlying variational inequalities. The existence result for this dynamical problem is obtained by using a priori estimates established for Faedo–Galerkin approximations, and some more specific techniques such as anisotropic Sobolev embedding theory.

Composite Fretting Wear of Aluminum Alloy

2007 ◽  
Vol 353-358 ◽  
pp. 868-873 ◽  
Author(s):  
Min Hao Zhu ◽  
Zhong Rong Zhou
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Relative Motion ◽  
Wear Mechanism ◽  
Normal Force ◽  
Fretting Wear ◽  
Test Results ◽  
Contact Configuration ◽  
Inclined Angle ◽  
Flat Contact

A complex relative motion of fretting combined by dual motions of radial and tangential fretting was achieved on a modified fretting tester. The composite fretting motion was induced by the action of an oscillating normal force in a sphere-on-inclined flat contact (52100 steel ball against 2091 aluminum alloy). Two types of inclined angles (45° and 60°) were used in the tests. Variations of veridical force vs displacement have been recorded and analyzed as a function of cycles. Effects of the cyclic normal force and the inclined angle were discussed. The test results showed that wear, cracking and plastic deformation accumulation with a strong dissymmetry in damage morphology was observed. A transformation of fretting mode from composite to radial fretting mode occurred due to a strong modification at local contact configuration. As a conclusion, a physical model for wear mechanism of composite fretting was presented.

scholarly journals A preservação de acervos históricos no estado de Minas Gerais: Projeto Memorial da Imprensa de Uberaba – criação da Hemeroteca Digital do Triângulo Mineiro e Alto Paranaíba (The preservation of historical...)

2015 ◽  
Vol 16 (25) ◽  
pp. 168
Author(s):  
Vilma Moreira dos Santos ◽  
Thiago Veloso Vitral ◽  
Alessandra Palhares
Keyword(s):  
Digital Library ◽  
Digital Libraries ◽  
Minas Gerais ◽  
Printing Press ◽  
Third Body ◽  
Main Achievement ◽  
Historical Collections ◽  
The Third ◽  
The Creation ◽  
Anglo American

<p>O Projeto <strong>Memorial da Imprensa de Uberaba: criação da Hemeroteca Digital do Triângulo Mineiro e Alto Paranaíba </strong>constitui, provavelmente, o maior investimento do estado de Minas Gerais em um projeto individual na área de preservação de acervos documentais históricos. O projeto conta com o financiamento da Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG). Foi concebido e vem sendo executado por parceria firmada entre a Secretaria de Estado de Ciência, Tecnologia e Ensino Superior (SECTES/MG) e a Secretaria de Estado de Cultura (SEC/MG), por meio do Arquivo Público Mineiro (APM), órgão coordenador do Projeto e da Superintendência de Bibliotecas Públicas (SUB). Conta ainda com a participação do Arquivo Público de Uberaba. A partir das diretrizes de regionalização da política cultural do Estado, o resultado principal do projeto será a implantação de um polo de digitalização de acervos documentais históricos no Arquivo Público de Uberaba, que deverá atuar como órgão catalizador e executor de projetos de digitalização nas regiões acima mencionadas. O projeto se fundamenta nas metodologias de organização, preservação e digitalização de acervos documentais preconizadas pelo <strong>Programa Conservação Preventiva em Bibliotecas e Arquivos</strong>, nas recomendações do Conselho Nacional de Arquivos (CONARQ) e nas regras do Código de Catalogação Anglo-americano (CCAA2).</p><p><strong><br /></strong></p><p><strong>Abstract</strong></p><p>“The Printing Press Memorial of Uberaba: the creation of the newspapers´ digital library of Triângulo Mineiro and Alto Paranaíba (Minas Gerais, Brazil)” is probably, the biggest project in the field of historical collections preservation ever funded by the Fundação de Amparo à Pesquisa do Estado de Minas Gerais – FAPEMIG. The project was conceived and has been carried out by the Secretaria de Estado de Ciência, Tecnologia e Ensino Superior, along with the Secretaria de Estado de Cultura, through the participation of the Arquivo Público Mineiro, the coordinating body, and the Superintendência de Bibliotecas Públicas. The<em> </em>Arquivo Público de Uberaba is the third body involved with the implementation of the project. In accordance with the regionalization policies of the State, the main achievement of the project shall be the creation of a digitalization center of historical collections in the Arquivo Público de Uberaba. This institution shall act as a regional agency for the development of digitalization projects in the regions of Triângulo Mineiro and Alto Paranaíba. The project is based on the methodologies of organization, preservation and digitalization of historical collections, recommended by the Programa de Conservação Preventiva em Bibliotecas e Arquivos, the guidelines of the Conselho Nacional de Arquivos<em> </em>(CONARQ) and the Anglo American Cataloguing Rules (AACR2).</p><p><strong>Keywords</strong>: Digitalization of Historical collections; Preservation of Historical Collections; Digital Libraries.</p>

scholarly journals Role of capillary adhesion in the friction peak during the tacky transition

Friction ◽  
2021 ◽  
Author(s):  
Tianyan Gao ◽  
Jiaxin Ye ◽  
Kaisen Zhang ◽  
Xiaojun Liu ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Indentation Depth ◽  
Normal Force ◽  
Normal Load ◽  
Pdms Film ◽  
Capillary Adhesion ◽  
Static Contact ◽  
Van Der Waals Attraction ◽  
Contact Experiments

AbstractThe friction peak that occurs in tire-road sliding when the contact changes from wet to dry was previously attributed to capillary cohesion, van der Waals attraction, and surface roughness, but the detailed mechanisms have yet to be revealed. In this study, friction and static contact experiments were conducted using a custom-built in situ optical microtribometer, which allowed us to investigate the evolution of the friction, normal load, and contact area between a polydimethylsiloxane (PDMS) film and a silicon nitride ball during water volatilization. The friction coefficient increased by 100%, and the normal force dropped by 30% relative to those in the dry condition during the wet-to-dry transition. In static contact experiments, the probe indentation depth increased, and the normal load decreased by ∼60% as the water evaporated. Combining the friction and static contact results, we propose that the large friction peak that appeared in this study can be attributed to the combined effects of increased adhesive capillary force and increased plowing during the wet-to-dry transition.

scholarly journals γ DOR: A PULSATING COMPONENT OF KIC 8043961 IN A STELLAR TRIPLE SYSTEM

2020 ◽  
Vol 56 (2) ◽  
pp. 179-191
Author(s):  
C. Kamil ◽  
H. A. Dal ◽  
O. Özdarcan ◽  
E. Yoldaş
Keyword(s):  
Major Axis ◽  
Primary Component ◽  
Mass Ratio ◽  
Third Body ◽  
Semi Major Axis ◽  
Orbital Inclination ◽  
The Third ◽  
New Findings ◽  
Effective Temperatures ◽  
Orbit Model

We present new findings about KIC 8043961. We find the effective temperatures of the components as 6900 ± 200 K for the primary, and 6598 ± 200 K for the secondary, while the logarithm of the surface gravities are found to be 4.06 cm s-2 and 3.77 cm s-2, respectively. Combination of the light curve with the spectroscopic orbit model results leads to a mass ratio of 1.09 ± 0.07 with an orbital inclination of 73.71 ± 0.14 and a semi-major axis of 8.05 ± 0.22 R⨀ . Masses of the primary and secondary components are calculated as 1.379 ± 0.109 M⨀ and 1.513 ± 0.181 M⨀, while the radii are found to be 1.806 ± 0.084 R⨀ and 2.611 ± 0.059 R⨀. In addition, we obtain a considerable light contribution (≈0.54%) of a third body. We compute a possible mass for the third body as 0.778 ± 0.002 M⨀. We find that the primary component exhibits γ Dor type pulsations with 137 frequencies.

Fretting Wear Mechanisms and Their Effects on Fretting Fatigue

1988 ◽  
Vol 110 (3) ◽  
pp. 517-524 ◽  
Author(s):  
Y. Berthier ◽  
Ch. Colombie´ ◽  
L. Vincent ◽  
M. Godet
Keyword(s):  
Fretting Fatigue ◽  
Relative Displacement ◽  
Contact Condition ◽  
Fretting Wear ◽  
Initial Contact ◽  
Great Care ◽  
Third Body ◽  
Body Formation ◽  
The Third ◽  
Contact Surfaces

Fretting wear and fretting fatigue are governed by the rate of formation of materials (third-bodies) between the initial contact surfaces. Furthermore, the third-bodies must be maintained within the contact. The issue of the race between third-body formation and subsurface damage conditions the effect of fretting on fatigue. That race lasts for only a few hundred or at best a few thousand cycles. Effective third-bodies (or good anti-fretting lubricants) must adhere strongly to the rubbing surfaces, and be able to accommodate at least part of the relative displacement. Great care in the design of test equipment has to be exercised before definitive results on the effect of amplitude and frequency on either fretting fatigue or fretting wear can be obtained for a given contact condition, given materials and given environments.

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