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Tytuł:
Intelligent microbearings project with memory of stress-strain history
Autorzy:
Wierzcholski, K.
Miszczak, A.
Kosowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/241991.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
Curvilinear grooved journals
micro bearing in computer disks
capacity memory simulations
Opis:
Taking into account the increasing need of intelligent micro-bearing with memory, this paper presents the optimization, simulation and practical application of operating parameters(load carrying capacity, friction forces, friction coefficient, wear), simulation for hydrodynamic HDD micro-bearing with curvilinear nano-grooved journal profile. One of the reason of such journal profile is that this journal profile contributes to the variation (an increase or decrease) the memory capacity of HDD drive operating on hydrodynamic micro-bearings. Such properties are very important and required in HDD micro-bearings. A general theory of materials with memory is the theory developed by Noll and Koleman. The simple solid body and liquid theory presented in this paper is based on the assumption that stress is defined by a whole deformation history. The changes of micro-bearing superficial surfaces presented in this paper are described by the process of changes of mass of a body system defined by non-classical intelligent oil and bearing material properties. Scientific problems considered in the paper are focused on comparisons and practical applications of tribological processes, which occur during fluid flow around cells lubrication on the nano-surfaces in bio-bearings as well as surfaces of micro-bearings used in micro-mechanisms. Up to now, the dynamic behaviour of HDD spindle system with fluid micro-bearings was considered by Jang at al. [7]. They simulated an increase in the memory capacity by increase in the bearing width and by application herringbone or spiral grooves on the sleeve and journal surfaces of HDD micro-bearings. After proposal contained in this project it is additionally possible to make capacity memory simulations by the various shapes of micro-bearing journal application.
Źródło:
Journal of KONES; 2008, 15, 4; 583-589
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The intelligent operation of nano-grooved microbearing surfaces in computer HDDS
Nanorowki na powierzchni mikrołożyska komputerowego HDD jako wkład do inteligentnej eksploatacji
Autorzy:
Wierzcholski, K.
Miszczak, A.
Khudoley, A.
Powiązania:
https://bibliotekanauki.pl/articles/187943.pdf
Data publikacji:
2012
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
HDD mikrołożyska
nanoprofile powierzchni roboczych
inteligentna eksploatacja
HDD-microbearing
nano-profiles of work surfaces
intelligent operation
Opis:
The nano- and micro-grooves on two cooperating micro-bearing surfaces depend strongly on the intelligent operation of computer HDDs. Therefore, the main topic of this paper is concerned with the influence of micro- and nanostructures in cooperating surfaces on intelligent micro bearing behaviour. The measurements are performed for a new, unused cooperating journals and sleeve surfaces of micro bearings in a new Hard Disc Driver 2.5, Samsung, HM 160 HI, 5400 rpm, utilising a atomic force microscope and scanning electron microscope and micro-x-ray analysis. The structure and geometry of nano-grooves and the composition of the roots in the material of the journal and sleeve alloy enables one to indicate the proper micro-bearing operation process and hydrodynamic lubrication model. These surfaces are radically different in comparison to cooperating surfaces occurring in micro bearings inside the computer ventilator. The presented measurements indicate that, in the micro-bearing gap, the changes of lubricant viscosity in the gap height direction have important implications on the HDD operation. In classical bearings such influences never occur.
Rezultaty badań naukowych dysków komputerowych przeprowadzone w ostatnich trzech latach w USA, Chinach i Japonii wykazały, że inteligentne właściwości eksploatacyjne HDD uzyskuje się dzięki mikro- i nanorowkom znajdującym się na powierzchniach mikrołożysk ślizgowych. Autorzy zauważyli, że w nieużywanych komputerowych HDD produkowanych na Tajwanie i Chinach kontynentalnych a także w Japonii występują różne geometrie nanorowków na powierzchniach mikrołożyska. Powierzchnie te zasadniczo różnią się od powierzchni mikrołożysk występujących w wentylatorkach komputera L. 8. Dlatego też są rozpatrywane w oddzielnym artykule. Specyficzna geometria rowków umożliwia niespotykaną w klasycznych łożyskach zmianę lepkości czynnika smarującego po grubości warstwy. Ten fakt powoduje wytworzenie dodatkowych sił nośnych, które przy świadomym ukształtowaniu geometrii nanorowków są celowo wykorzystywane w trakcie procesu eksploatacji twardych dysków komputerowych. W niniejszej pracy została przedstawiona analiza pomiarów dwóch nowych niezużytych współpracujących powierzchni mikrołożyska o obrotach 5400 rpm występujących w dysku twardym komputera HDD 2,5'' Samsung HM 160 HI wyprodukowanym w Chinach. Celem pracy jest interpretacja opracowanych pomiarów zawierających wymiary i geometrię oraz profile przekrojów poprzecznych nanorowków dla powierzchni roboczych czopa i panewki. Uzyskane wyniki pomiarów pozwalają ocenić i porównać zmiany geometrii nanorowków i ich profili przekroju poprzecznego w trakcie eksploatacji. Badania takie mogą być również pożyteczne dla konstruktorów w trakcie projektowania i budowy mikrołożysk HD.
Źródło:
Tribologia; 2012, 1; 157-166
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of non used microbearing grooved surfaces for computer ventilator Xilence Case Fan
Autorzy:
Wierzcholski, K.
Miszczak, A.
Khudoley, A.
Powiązania:
https://bibliotekanauki.pl/articles/245823.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
computer ventilator Xilence Case Fan
microbearing
grooves
profiles of work surfaces
Opis:
In this paper is presented the measurement analysis of two a new non-damaged cooperating microbearing surfaces occurring in computer ventilator Xilence Case Fan 92mm. Elaborated measurements concern Scanning Electron Microscope (SEM) images of journal and sleeve work surfaces, AFM roughness tests with 3D images of journal and sleeve work surfaces and profiles of their cross sections, Vickers micro-hardness value studies for journal and sleeve surface. Furthermore in researches of the sleeve surface are included measurements for macro-profile surfaces with herringbone grooves micro-profiles of small grooves utilizing and Atomic Force Microscope) AFM - NT-206 Belarus. The measurements are performed for a new non damaged journal and sleeve surface using the AFM and SEM & Micro-X-Ray analysis. Such analysis concerns results referring to the bearing material composition with standard deviation of measured values. The view of cylindrical microbearing journal surfaces with nano-ridges and grooves and measured non used and non damaged surfaces with longitudinal nano-ridges and grooves in cylindrical slide microbearing journal and sleeve; SEM image of work surface of the microbearing journal and microbearing sleeve of computer ventilator Xilence Case Fan, 3D AFM image of work surface of microbearing journal, profile of work surface of the journal, 3D AFM image of work surface of microbearing sleeve of computer ventilator, profile of work surface of the sleeve are presented in the paper.
Źródło:
Journal of KONES; 2011, 18, 2; 471-476
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Samooczyszczające się hydrofobowe systemy tribologiczne
Self-cleaning hydrophobic friction systems
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/188012.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
powierzchnie hydrofobowe
adhezja
samooczyszczanie
hydrophobic surface
anti-adhesion
self-cleaning
Opis:
Procesy adhezyjne lub mechanizmy tribologiczne są interesujące z wielu powodów. Biologiczne mechanizmy kontaktowe pomagają w zrozumieniu zasad funkcjonowania wielu technicznych adhezyjnych urządzeń. Zbadanie biologicznych stykowych powierzchni stało się źródłem rozwoju idei twórczych w zakresie przemysłowych zastosowań powierzchni samo-oczyszczających się. Na przykład powierzchnie samooczyszczające są bardzo pożądane w zbiornikach do magazynowania olejów, smarów, farb. Ponadto powierzchnie lemieszy pługa powinny też posiadać własność samooczyszczania się od pozostałości gleby po orce. Zdolność samooczyszczania powierzchni jest procesem tribologicznym. Powierzchnie hydrofobowe charakteryzują się specyficzną rzeźbą w postaci mikroi nanorowków. W pracy wyjaśniono mechanizm zanieczyszczenia powierzchni tworzony adhezyjnym wiązania nanoobiektów z rozpatrywanymi powierzchniami na skutek sił Van der Waalsa.
Adhesive or sticking tribological mechanisms are interesting in several respects. Biological sticking mechanisms may aid in understandding the principles of the functioning of other technical frictional and adhesive mechanisms. Biological sticking surfaces provide a rich source of ideas for the development of industrial applications, such as self cleaning surfaces. For example, the self-cleaning surfaces are very desirable for the internal surfaces of tanks for lubricants in contact with the oil. The shared surfaces of the plough ought to have self-cleaning properties too. Self cleaning-abilities of the surface are known as the hydrophobic properties. Hydrophobic surfaces have specific sculptured shapes with the nano-ridges and nano-grooves. Particle contaminating surface structures consists, in most cases, of material that is more readily wetted than hydrophobic wax components. Contaminants usually rest on the tips of the surface structures, so that the real contact area between the particles and sculptured surface is minimised. Thus, these particles can be easily removed by water droplets rolling over the surface. In this case, the adhesion between particles and water droplets is greater than between particles and the sculptured surface due to the reduced contact between the particles and surface. Therefore, we have the selfcleaning process of the surface.
Źródło:
Tribologia; 2010, 3; 241-250
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorytm wyznaczania zmiennych współczynników pseudolepkości olejów na bazie eksperymentu
Algorythm for variable pseudoviscosity coefficients under an experimental basis
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/188532.pdf
Data publikacji:
2013
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
związki fizyczne
zmienne współczynniki pseudolepkości
wpływ prędkości deformacji
oleje smarujące
physical dependencies
changes of pseudo-viscosity coefficients
share rate influences
lubrication oils
Opis:
Obserwuje się coraz większy udział stosowania olejów częściowo i całkowicie syntetycznych w procesie smarowania węzłów tarcia ślizgowego. Oleje te charakteryzują się nienewtonowskimi właściwościami. Nienewtonowskimi olejami nazywa się takie ciecze, w których oprócz klasycznych zależności lepkości oleju od ciśnienia i temperatury występuje dodatkowo zależność lepkości od prędkości deformacji. Większość czynników smarujących ulepszanych chemicznie ma właściwości nienewtonowskie. Podobnie ciecze zanieczyszczone, np. substancjami organicznymi, kurzem ulicznym, sadzą lub też produktami zużycia i spalania w silniku spalinowym wykazują właściwości nienewtonowskie. Wymienione zanieczyszczenia i dodatki mogą powodować wzrost lub spadek lepkości czynnika smarującego w stosunku do bazowej cieczy smarującej. W niniejszej pracy przedstawiona została metoda analityczna wyznaczania zmiennych wartości funkcyjnych współczynników pseudolepkości na podstawie wyników eksperymentalnych dla olejów stosowanych w praktyce inżynierskiej.
Constitutive equations between stresses and deformations for oils with pseudo-viscosity properties are usually described by the Rivlin-Ericksen relations. In these relations two pseudo-viscosity coefficients occur. Up to now, in numerous scientific papers concerning the journal bearing lubrication with visco-elastic oils, the mentioned pseudo-viscosity coefficients have been treated as constant values. By virtue of performed measurements, it is evident that experimental curves describing visco-elastic oil dynamic viscosity versus shear rate had shapes that cannot be obtained for the constant pseudo-viscosity coefficients. In this case, only possible are the unknown dependences between oil dynamic viscosity and share rate. This paper shows the algorithm derivation for variable pseudo-viscosity coefficients as a function of shear rate using pseudo-viscosity oils and taking into account the experimental data obtained from viscosity measurements.
Źródło:
Tribologia; 2013, 4; 125-136
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magneto-therapy of human joint cartilage
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/306552.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
magnetoterapia
pole magnetyczne
efekty magnetoterapii
magnetic induction variable field
magnetotherapy
magneto electronic devices
positive effects of magnetotherapy
negative effects of magnetotherapy
human joint cartilage diseases
Opis:
Purpose: The topic of the present paper concerns the human joint cartilage therapy performed by the magnetic induction field. There is proved the thesis that the applied magnetic field for concrete cartilage illness should depend on the proper relative and concrete values of applied magnetic induction, intensity as well the time of treatment duration. Additionally, very important are frequencies and amplitudes of magnetic field as well as magnetic permeability of the synovial fluid. Material and methods: The research methods used in this paper include: magnetic induction field produced by a new Polish and German magneto electronic devices for the therapy of human joint cartilage diseases, stationary and movable magnetic applicators, magnetic bandage, ferrofluid injections, author’s experience gained in Germany research institutes and practical results after measurements and information from patients. Results: The results of this paper concern concrete parameters of time dependent electro-magnetic field administration during the joint cartilage therapy duration and additionally concern the corollaries which are implied from reading values gained on the magnetic induction devices. Conclusions: The main conclusions obtained in this paper are as follows: Time dependent magnetic induction field increases the dynamic viscosity of movable synovial fluid and decreases symptoms of cartilage illness for concrete intensity of magnetic field and concrete field line architecture. The ferrofluid therapy and phospholipids bilayer simultaneously with the administrated external electromagnetic field, increases the dynamic viscosity of movable synovial fluid.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 1; 115-124
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new problem of hydrodynamic lubrication with temperature and viscosity variations in gap height direction
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/245652.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
liquid viscosity changes in thin gap height direction
temperature
adhesion or capillary forces variations in thin gap height direction new analytical solutions
Opis:
Numerous Authors of scientific papers occurring in hydrodynamic theory of slide bearing lubrication, up to now almost always had neglected the oil dynamic viscosity variations caused by temperature, adhesion forces, capillary forces, or hydrogen ion concentration across the film thickness by virtue of the statement of the constant temperature as well constant adhesion as capillary forces in the thin bearing gap height direction. In addition, simultaneously by virtue of boundary layer simplifications for energy equation and by virtue of new measurements performed in micro and nano- level follows that oil temperature gradients and its values differences and adhesion or capillary gradients of forces in bearing gap height directions are not negligible small. The contemporary hydrodynamic theory of lubrication for non-isothermal lubricant flow is unfortunately based on the assumption of constant viscosity values across the film thickness, despite abovementioned self-evident contradiction between the fact of constant viscosity and simultaneously temperature variations in gap height direction. Such problem was up to now not sufficient critical examined and explained in practical and theoretical sense. After Authors, knowledge by virtue of above problem the most scientific papers in the domain of non-isothermal and lamellar hydrodynamic slide bearing or biobearing lubrication were up to now not sufficient correctly solved. It denotes that the main hydrodynamic lubrication solutions presenting for example hydrodynamic pressure by the modified Reynolds equation and temperature by the energy conservation equation are not sufficiently correctly obtained and next not correctly solved. Therefore are assumed simultaneously the temperature T and oil dynamic viscosity variations in length, width and bearing gap- height directions. From this assumption follows, that the energy equation must be solved simultaneously with the equations of motion i.e. consequently with pressure equation where viscosity depends on temperature and temperature depends on the coordinate in gap height direction.
Źródło:
Journal of KONES; 2016, 23, 2; 423-430
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adhesion and capilarity in micro-bearing lubrication
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/245795.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
adsorption
adhesion
capillary forces
micro-bearing lubrication
Opis:
Present paper shows the some main phenomena which have important influence on the micro-bearing operating parameters. To above mentioned phenomena belong: adhesion forces, adsorption forces, capillary forces, elastic and hyperelastic deformations of cooperating micro-bearing surfaces, Van-der Waals electrostatic forces on the micro-bearing surfaces. Because the height of super thin micro-bearing gap is very small often smaller than l micrometer, hence the adhesion forces and capillary forces arising in micro-bearing gap, provoke the oil dynamic viscosity changes. This fact leads to the hydrodynamic pressure and bearing carrying capacity changes. The performed research play off the main role of mechanical micro-deformations of cooperating micro-bearing surfaces on non-Newtonian oil dynamic viscosity and here are indicated the influence of capillary force on adhesion forces in micro-scale. The micro-deformations of the micro-bearing gap height are effecting the changes of oil flow velocity in the gap, this fact leads to the share rate changes and therefore we obtain changes of apparent viscosity of the non-Newtonian oil.
Źródło:
Journal of KONES; 2009, 16, 3; 489-495
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic field impact on the temperature and pressure distribution in slide journal bearing
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/246908.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
slide journal bearing
magnetic induction field
non-Newtonian lubricant
conjugated fields
new general method
load carrying capacity
pressure decrements
pressure increments
Opis:
The topic of the presented article aims to demonstrate a new principle of hydrodynamic lubrication in mechanical, non-isothermal and electro-magnetic fields. In this article is presented hydrodynamic slide journal bearing in electromagnetic field. The aim of this article is a new general analytical and numerical solution determined the influence of the electro-magnetic field on the temperature distribution in the internal surfaces of the slide-bearing sleeve and pressure distribution in bearing gap. To the research methods and materials used in this article realization belong: the Mathcad 15 Professional Program and new semi-analytical methods applied for theory of hydrodynamic lubrication extended to the curvilinear orthogonal surface and coordinates. Particular solutions are introduced to the cylindrical coordinates. To the obtained results of lubrication of movable sleeve surface belong the increments of the bearing load carrying capacity during the presence and absence magnetic induction field in the case if non-Newtonian lubricant features and constant temperature are taken into account. Simultaneously are observed the increments of the bearing load carrying capacity during the presence magnetic field and Newtonian lubricant. Temperature increments (decrements) without and with magnetic field lead to the hydrodynamic pressure decrements (increments). Moreover are assumed simultaneously the temperature T and oil dynamic viscosity variations in length, width and bearing gapheight directions. From this assumption follows, that the energy equation must be solved simultaneously with the equations of motion i.e. consequently with pressure equation where viscosity depends on temperature and temperature depends on the coordinate in gap height direction.
Źródło:
Journal of KONES; 2017, 24, 2; 279-286
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Friction forces on the lubricated surfaces in micro and nano scale
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/241987.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
AFM
experimental data
dynamic friction forces
Opis:
The present paper determines static and dynamic friction forces and friction coefficients using atomic force microscope during the hydrodynamic viscoelastic liquid flow in the thin boundary layer around the cells of two cooperating bodies. Atomic force microscope is necessary in performed experimental investigations and measurements of friction forces. Therefore, proper parameters of microscope are described and illustrated in specific enlargement. The use of microscope of atomic forces AFM for complex technical investigations to a large extent has facilitated carrying-out the measurements of tissue surface features and control of its growing process in human joint and deforming process in micro-bearing alloy. During conventional nano-scale measurements of surface topography, the AFM microscope makes it possible to simultaneously map local lateral forces and oscillatory phases of translations, which may be interpreted as a representation of local friction forces and local adhesive forces as well as values of elasticity modules. One of the important advantages of the AFM microscope application in the area of investigations with the use of bio-reactors is the possibility of carrying out measurements directly in liquid, namely that surrounds the cells or micro-bearing gaps
Źródło:
Journal of KONES; 2008, 15, 4; 597-602
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The project of memory and genetic code simulations for joint lubrication
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/241989.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
Curvilinear bone heads
capacity memory simulations
genetic code of biological liquids
Opis:
This paper presents the optimization, simulation and practical application of operating parameters(load carrying capacity, friction forces, friction coefficient, wear) for hydrodynamic intelligent articular and artificial bio-bearing joints with curvilinear nano-shaped surfaces. One of the reason of such bone head and endoprosthese profile is that this profile contributes to the variation (an increase or decrease) the memory joint capacity. Such properties are very important and required in human joints. A general theory of materials with memory is the theory developed by Noll and Koleman. The simple solid body and liquid theory presented in this paper is based on the assumption that stress is defined by a whole deformation history. The changes of bio-bearing superficial surfaces presented in this paper are described by the process of changes of mass of a body system defined by non-Newtonian synovial liquid properties and its genetic (congenital) factors, which depends on epigenetic (environmental) factors (temperature, mechanical stress and strain, internal and external physical fields, etc.). Scientific problems considered in the paper are mainly focused on comparisons and practical applications of tribological processes, which occur during fluid flow around cells lubrication on the nano-surfaces in nano-bearings, as well as surfaces of bio-bearings.
Źródło:
Journal of KONES; 2008, 15, 4; 591-596
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differential and recurrence unified reynolds equations and mega algorithm for their numerical solutions
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/242919.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
partial differential form
partial recurrence form
unified Reynolds equation
mega algorithm
Opis:
The objective of the research under the paper topic is an analytical, unified formulation of a new standardized view of general solution of hydrodynamic problem using algorithm to determine changes of the components of the velocity vector, the distributions of hydrodynamic pressure, load carrying capacity, of slide bearings with cooperating curvilinear, orthogonal surfaces that are lubricated with a various non-Newtonian lubricants. In this paper for non- Newtonian lubricants are questioning the hitherto prevailing assumptions using in hydrodynamic theory of lubrication such as constant value of lubricant viscosity and pressure in the thickness of lubricating gap i.e. in gap height direction. Finally, the non-homogeneous partial differential equation generated with variable coefficients that is the result of the various boundary conditions being imposed that are different for each problem solved is an equation that determines the distributions of hydrodynamic pressure values. This equation is to be written in the form of a unified non-homogenous partial recurrence equation with variable coefficients. The Authors foresee that a mega-algorithm will be developed for the solution of this equation in a numerical form. This equation in particular cases is an equivalent of modified Reynolds equations in the research that has been conducted so far concerning the hydrodynamic theory of lubrication.
Źródło:
Journal of KONES; 2012, 19, 4; 643-650
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impulsive and periodic class of solutions for hydrodynamic theory of lubrication
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/242922.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
injury solutions
periodic solutions
theory of lubrication
partial differential equations
Opis:
In this paper, two different classes of lubricant flow conditions are basically indicated, i.e. for periodic solutions when pressure values and other flow parameters change periodically and for non-periodic solutions in the case of lubricating in the conditions of impulses and strokes. The Authors formulate the primary problem in the form of a system of 9 nonlinear non-homogeneous partial differential equations with variable and random coefficients in a curvilinear orthogonal system of coordinates which is supplemented with suitable constitutive dependences and conjugated with magnetic field equations with the Ohm equation. These equations include the following: three conservation equations of the lubricating liquid momentum, the stream continuity equation, the energy conservation equation, three equilibrium equations of the thin elastic superficial layer that are reduced to the differential equation in displacements, the heat transfer equation of the superficial layer that is flown around by the lubricating liquid. The following include those equations that describe constitutive dependences the Rivlin-Ericksen equation of physical dependences for viscoelastic ferrofluid, the equation of the physical dependences of the superficial layer of the surfaces lubricated, the equation of the physical dependences of the magnetic field. The unknown values of the material coefficients shall be determined experimentally. The following 9 unknowns are determined from the system of partial differential equations: three velocity components of the lubricating liquid, the hydrodynamic pressure, the temperature in the lubricating liquid, the three components of the superficial layer displacement and the temperature in the superficial layer. The mathematical solution of the problem presented requires a number of boundary conditions to be imposed. The Authors foresee quasi-analytical solutions of the system described of partial differential equations.
Źródło:
Journal of KONES; 2012, 19, 4; 651-658
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scientific achievements obtained in the project MTKD-CT-2004-517226 in years 2005-2008
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/243524.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
hydrodynamic pressure
hyperelastic human joints
deformable gap
Opis:
The synovial joint has two main components: solid one represented by the cartilage, and bio-fluid by the synovial fluid. The cartilage is a soft anisotropic solid containing pores filled with a fluid. In this paper is determined the pressure distributions in a thin layer of non-Newtonian, lubricant inside the deformable gap of spherical human hip joint. The load carrying capacities in human joints with cartilage deformations are much smaller than that obtained for not deformable cartilage surface. The changes of the joint gap height during the lubrication process are caused by the deformation of two cooperating spherical joint surfaces covered by the soft cartilage superficial layer. Hypo-elastic deformations of cartilage are taken into account. In the general case the cartilage can be subjected to large deformations. The main results described in this paper are as follows: 1.Numerical calculated values of pressure distributions for the elbow cylindrical human joints performed in this paper by virtue of analytical models taking into account the effects of congenial and growth influences on the lubrication process are compared with initial measured hydrodynamic pressure values performed by means of AFM. Measured pressure values obtained by the S. Chizhik et al. 2006 in experimental way, are different about 7 percent from the numerical values obtained in presented paper using the analytical solutions. 2.In presented paper is derived the modified Reynolds equation containing the terms describing the influences of congenial and genetic properties of the lubricant and micro-bearing materials on the pressure and load carrying capacity of bio-joints and micro-bearing. The comparisons presented in this project between human bio-joints and micro-bearings are indicated that the biobearing theory of lubrication is very helpful in MEMS and NEMS devices. The research presented in the project provides an important impact for developing the new scientific domain such as cyto-tribology, histo-tribology or tribology of cells, and tissue and of micro-surfaces occurring in mechanical micro-bearings. According to the participants knowledge such scientific domains are completely new and have been not so far initiated by any scientific centre and in any area of tribology and tissue engineering.
Źródło:
Journal of KONES; 2008, 15, 3; 543-549
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The robot joint lubrication with ultra-thin hyperelastic superficial layers
Autorzy:
Wierzcholski, K.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/243815.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
robot joint lubrication
various curvilinear hyperactive thin
soft layer shapes
basic hydrodynamic equations
physical models
humanoid robot
Opis:
The surface of humanoid robots is more or less deformable metal and plastic replica of human body. An advanced humanoid robot has human like behaviour – it can talk, run, jump or climb stairs in a very similar way a human does. Hence follows that operation of construction of the robots artificial joints to be similar for biological joints activities. This fact requires applying proper as well corresponding soft solid materials, and specific lubricants. To the interesting phenomena belong the fact, that as well the surfaces of an articular cartilage human joint as the soft surfaces of the robot joints, coated with ultra-thin hyperelastic multi-layers, plays an important role in the surface active lubrication, relative small friction forces and wear during the human limb or robot body activities in the movement. The presence of the ultra-thin hyperelastic layers consisting the soft bearing materials including hyperelastic nano-particles during the robot bearing lubrication enables to indicate numerous positive effects among other the decreases the friction coefficient values. Therefore, the results obtained in this paper may be applicable during the joint-endo-prosthesis or artificial joint design in new humanoid robots, where instead cartilage and synovial fluid are applied new soft materials with active hyperelastic micro- and nano- particles. In this paper is shortly presented the mathematical model of hydrodynamic lubrication of thin boundary layer describing the robot joint. Mathematical model in 3D for lubricant consists of three equations of motion, continuity equation, conservation of energy equation and Young-Kelvin-Laplace equation describing the thin layer interfacial energy.
Źródło:
Journal of KONES; 2016, 23, 3; 555-562
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 43

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