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1

Sliding Composite Material Including Glassy Carbon as a Solid Lubricant

Posmyk Andrzej, Myalski Jerzy, Myalska-Głowacka Hanna

Tribologia

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2024

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nr 4

85--91

EN

The article presents the basics of producing a sliding composite based on a hypoeutectic aluminum alloy reinforced with glassy carbon foam designed for oil-free contacts of machines and devices. The foam with an open porosity of 90% was infiltrated with liquid silumin. The tribological properties of the matrix material and the produced composite were tested in cooperation with GJL-250 gray cast iron on a pin-on-disc tester. A cast iron pin with a diameter of 5 mm slid on discs with a diameter of 45 mm at a velocity of 0.5 m/s and a pressure of 0.25 MPa. Tests were performed in technically dry friction conditions and with limited lubrication by a single application of 2 mg of oil to the friction zone. As a result of the research, it was found that the presence of 10% of glassy carbon enables the sliding of cast iron against AlSi9NiCuMg silumin under technically dry friction conditions, reducing its wear by 15% and the friction coefficient by 20% at the beginning and by 18% at the end of sliding. With limited lubrication, composite disc wear is nine times lower than in the case of a silumin disc and pin wear is almost immeasurable. This confirms the effectiveness of glassy carbon as a solid lubricant.

PL

W artykule przedstawiono podstawy wytwarzania kompozytu ślizgowego na osnowie podeutektycznego stopu aluminium zbrojonego pianką z węgla szklistego przeznaczonego na bezolejowe skojarzenia maszyn i urządzeń. Piankę o otwartej porowatości 90% infiltrowano ciekłym siluminem. Właściwości tribologiczne materiału osnowy i wytworzonego kompozytu badano we współpracy z żeliwem szarym GJL-250 na testerze „pin-on-disc”. Żeliwny trzpień o średnicy 5 mm ślizgał się po tarczach o średnicy 45 mm z prędkością 0,5 m/s przy nacisku 0,25 MPa. Wykonano badania w warunkach tarcia technicznie suchego i z ograniczonym smarowaniem przez jednorazowe podanie 2 mg oleju do strefy tarcia. W wyniku badań stwierdzono, że obecność 10% węgla szklistego umożliwia współpracę żeliwa z siluminem AlSi9NiCuMg w warunkach tarcia technicznie suchego, zmniejszając jego zużycie 15% i współczynnik tarcia o 20% na początku i o 18% na końcu współpracy. Przy ograniczonym smarowaniu zużycie tarczy kompozytowej jest dziewięciokrotnie mniejsze niż siluminowej, a zużycie trzpienia prawie niemierzalne. Potwierdza to skuteczność działania węgla szklistego jako smaru stałego.

2

Verification of the road construction quality of concrete pavement in terms of skid resistance assessing

Wasilewska Marta, Gierasimiuk Paweł, Zadrożny Krzysztof

Materiały Budowlane

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2024

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nr 11

86--96

EN

The paper presents a comparison of friction coefficient results obtained with two SRT-3 devices on a concrete surface before the consent for its use. Measurements were taken in four locations on the S7 expressway. The surface was made using exposed aggregate textured concrete technology. Results were recorded after shotblasting and hydroblasting of the pavement. Significant differences were shown between the reliable friction coefficients (above 0.05) obtained with two devices on the same sections on the same day or in short time intervals. As a consequence, the condition of the road surface cannot be clearly verified. Therefore, the source of variability should be determined and tools that would prevent obtaining divergent results should be implemented in the quality control system. Otherwise, the results do not guarantee a reliable assessment of the surface in terms of preventing its slipperiness and thus user safety.

PL

W artykule porównano wyniki współczynnika tarcia na nawierzchni betonowej przed oddaniem jej do użytkowania i w jego okresie otrzymane dwoma urządzeniami SRT-3. Pomiary te prowadzono w czterech lokalizacjach drogi ekspresowej S7. Nawierzchnię wykonano w technologii betonowej teksturowanej metodą odkrytego kruszywa. Na dwóch odcinkach, spośród czterech, ocenę właściwości przeciwpoślizgowych prowadzono po zabiegach śrutowania i hydroblastingu. Wykazano istotne różnice pomiędzy miarodajnymi współczynnikami tarcia (powyżej 0,05) otrzymanymi dwoma urządzeniami na tych samach odcinkach, w tym samym dniu lub w krótkich odstępach czasu. W konsekwencji nie było możliwe jednoznaczne zweryfikowanie stanu nawierzchni pod kątem oceny właściwości przeciwpoślizgowych. Należałoby określić źródło zmienności i wdrożyć do kontroli systemu jakości takie narzędzia, które zapobiegałyby otrzymaniu rozbieżnych wyników. W przeciwnym wypadku wyniki nie gwarantują rzetelnej oceny nawierzchni w aspekcie zapobiegania jej śliskości, a tym samym bezpieczeństwa użytkowników.

3

Comparison of methods to determine the texture based on measurements with various profilometers

Wasilewska Marta, Wesołowski Mariusz, Blacha Krzysztof

Materiały Budowlane

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2024

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nr 7

53--63

EN

The paper presents a comparative analysis of the results of the MPD (Mean Profile Depth) parameter based on three methods for determining the texture of airport pavements using a dynamic profilometer (2D/3D scan CHS (CONTROL HIGH-SPEED scanner)) and stationary profilometers (Circular Track Meter; ElaTexture). The measurements were performed on test sections with different surface technologies, which were located on the Warsaw-Modlin Masovian Airport. Using the R&R (repeatability & reproducibility) method, the ability of measurement systems to monitor the texture was analyzed. The expanded uncertainty of EV (Equipment Variability) repeatability was 0.066 mm, and AV (Appraiser Variability) repeatability was 0.169 mm. The value of repeatability and reproducibility %R&R equal to 21.9% proves that the source of variability in obtaining MPD results is the difference in the recorded area of the test surface in individual measurement systems. Additionally, measurements of the friction coefficient were carried out using the ASFT tester (Airport Surface Friction Trailer), which enabled verification of the skid resistance of the test sections in relation to changes in their texture.

PL

W artykule przedstawiono analizę porównawczą wyników badania parametru MPD (Mean Profile Depth) z wykorzystaniem profilometru dynamicznego (Skaner 2D/3D scan CHS (CONTROL HIGH-SPEED)) i profilometrów stacjonarnych (Circular Track Meter; ElaTexture), które są przeznaczone do oceny tekstury nawierzchni lotniskowych. Pomiary wykonano na odcinkach testowych o zróżnicowanej technologii nawierzchni dróg kołowania Mazowieckiego Portu Lotniczego Warszawa – Modlin. Wykorzystując metodę R&R (repeatability & reproducibility) dokonano analizy zdolności systemów pomiarowych do monitorowania tekstury. Niepewność rozszerzona powtarzalności EV (Equipment Variability) wyniosła 0,066 mm, a odtwarzalność AV (Appraiser Variability) 0,169 mm. Wypadkowa wartość powtarzalności i odtwarzalności %R&R równa 21,9% świadczy, że źródłem zmienności w pozyskiwaniu wyników MPD jest różnica w rozmieszczeniu czujników w poszczególnych systemach pomiarowych, rejestrujących profile powierzchni. Dodatkowo przeprowadzono pomiary współczynnika tarcia testerem ASFT (Airport Surface Friction Trailer), które umożliwiły weryfikację właściwości przeciwpoślizgowych odcinków testowych w odniesieniu do zmian w ich teksturze.

4

Experimental investigation of the movement patterns and deformation of the pigs when passing through a pipe elbow and reducer

Stetsiuk S. M., Doroshenko Ya. V., Doroshenko Yu. I., Filipchuk O. O., Grudz V. Ya.

Journal of Achievements in Materials and Manufacturing Engineering

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2024

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Vol. 124, nr 2

49--64

EN

Purpose: Experimentally investigate the movement dynamics of the pigs having various geometric shapes through the pipeline elbows and adapters manufactured from various hyperelastic materials, and assess the risks of their getting stuck in such elements. Experimentally determine the required pressure in the behind-pig space for the experimental pig prototypes to pass through the pipeline elbows and adapters. Design/methodology/approach: Pig prototypes of various geometric shapes (cup-type, cylindrical two-disc type, multi-disc type, dumbbell disc type and three-ball dumbbell type) were designed in order to carry out the experimental investigation. Based on pigs' 3D models, the 3D models of casting mould have been designed and printed on a 3D printer. Pig prototypes were manufactured by filling the casting moulds with silicone compound with hardness of 30 units by Shore A hardness scale and polyurethane with hardness of 80 units by Shore A hardness scale. An experimental glass pipeline was designed and mounted to monitor the dynamics of the solid-cast pig prototype movement through the pipeline elbows. Video recordings of the process allowed us to identify and describe the patterns of pig prototype deformations in the glass pipeline elbow. Pressure was measured in the behind-pig space during the movement of pig prototypes through straight sections, the elbow and the adapter of the experimental pipeline made of metal. Measurements were taken for dry and wet inner walls of glass and metal pipelines. Findings: Cup-type pigs made of silicone compound showed best results in passing through the elbows at the lowest pressure in the behind-pig space (0.33 kgf/cm2). However, suppose the inner wall of the pipeline is dry. In that case, the pig tightness is lost in the pipeline elbow due to significant deformation of the pig, which causes the behind-pig space pressure to increase to 0.71 kgf/cm2 and augments the risk of the pig getting stuck. The dumbbell disc-type and three-ball dumbbell-type pigs made of silicone compound also show good results in passing through the elbows with low pressure in the behind-pig space (up to 0.5 kgf/cm2). Polyurethanepigs are highly rigid; therefore, for them to pass through the pipeline elbows, the pressure in the behind-pig space should be 2-4 times higher than for pigs made of silicone compound. Only the cup-type pig made of silicone compound can pass through the reducing pipe adapters with pressure in the behind-pig space being at least 8 kgf/cm2. Research limitations/implications: The investigation was performed in experimental mode. Further investigation will entail mathematical and numerical modelling of the pig prototypes movement through the pipeline elbows and adapters. Practical implications: The results obtained during the investigation will help to develop a more thorough approach to planning the process of using the pigs to clean the pipelines with elbows and reduce adapters. They allow us to choose the geometric shape and material of the pigs, taking into account the pipeline operating parameters (inlet pressure and flow rate). It is especially appropriate during the first planned pipeline cleaning with pigs. It allows us to minimize the risk of pigs getting stuck in the pipeline. Originality/value: The subject of investigation is patterns of the pig`s friction coefficient, material hardness and geometric shape, impacting its ability to pass through the elbows and reducing adapters, and the value of the required pressure in the behind-pig space.

5

Evaluation of the effects of the application of Ti−C:H DLC coatings obtained by PVD techniques in the kinematic pairs of internal combustion engines and powertrain systems

Murzyński Dawid

Combustion Engines

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2024

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R. 63, nr 3

27--33

EN

The article attempts to analyze the possible effects of using Ti−C:H DLC carbon coatings produced by pulsed magnetron sputtering (PVD) to reduce friction coefficient and wear in kinematic pairs found in internal combustion engines and powertrain systems used in automotive vehicles. The aim of such action is primarily to reduce internal losses in the aforementioned units. The coatings were deposited on heat-treated bearing steel 100Cr6, and examined using a scanning electron microscope FEI Quanta 200 Mark II with the chemical analyzer EDS EDAX Genesis XM 2i, tribotester T−01M examining the friction coefficient in the ball-disc correlation and Hommel Werke T8000 profilometers, additionally, in order to check the coating thickness, studies were carried out using the Calotest method. The results obtained indicate that both the friction coefficient and wear are drastically reduced concerning samples on which no DLC coatings were applied.

6

Numerical insights into stress changes induced by longwall mining in faulted rock masses

Tajduś Antoni, Flisiak Jerzy, Tajduś Krzysztof

Archives of Mining Sciences

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2024

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Vol. 69, no. 4

615--632

EN

Conducting mining operations in fault zones is a very challenging task, both from a technological perspective and also due to the safety of the miners. Therefore, it is essential to determine the impact of mining parameters on the possibility of fault activation, which in many cases leads to high seismic activity. The article presents the results of numerical analyses of the impact of longwall mining in the vicinity of tectonic faults on the state of stress in the rock masses. The authors demonstrated the influence of the advancement of the longwall face and its direction on the risk of rock burst, both for mining conducted in the footwall and hanging wall.

7

The effect of dispersing agents on the electrophoretic deposition, morphology and adhesion strength of multicomponent TiN/PTFE/PEEK coatings

Fiołek Aleksandra, Zimowski Sławomir, Moskalewicz Tomasz

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e48, 2024

EN

In this work, multicomponent PEEK coatings with PTFE particles and TiN nanoparticles were developed on Ti-6Al-4V alloy substrates using electrophoretic deposition (EPD) and post-EPD heat treatment. Three different polyelectrolytes involving chitosan, PAZO and sodium alginate were used to enable the co-deposition of all particles on one electrode. All polyelectrolytes were effective and enabled coating deposition through electrosteric stabilization of suspension. The EPD mechanism consisted of the adsorption of the dispersant on the surface of the particles and the imparting of a positive (chitosan) or negative (PAZO, sodium alginate) charge. Heat treatment densified the coatings but also caused microcrack formation in the coating with chitosan, shrinkage of the polymers in the coating with PAZO, and open porosity in the coating with sodium alginate. Coatings obtained from suspension with chitosan showed excellent adhesion strength and scratch resistance, higher that those deposited from suspensions containing PAZO or alginate. The introduction of TiN and PTFE particles into the PEEK matrix resulted in a simultaneous reduction of the friction coefficient and wear rate of the titanium alloy in the case of coatings with chitosan and alginate. These coatings are promising for improving the wear and friction properties of titanium alloys.

8

Study on the friction coefficient between eggshells and powders with various chosen surfaces

Wozniak Marek, Kuchar Maciej, Zakrzewski Sergiusz, Siczek Krzysztof, Obraniak Andrzej, Rylski Adam, Kubiak Przemyslaw

Technologia i Jakość Wyrobów

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2023

|

R. 68

111--151

EN

Transport of fresh or powdered chicken eggs uses conveyors with elements made of steel or plastics, and surfaces often coated by Teflon. Various forms of eggs contact with said surfaces and are subject to friction processes between them. The frictional resistances cause a load on the devices driving the conveyors and a local and temporary increase in temperature in the contact zones and allow the abrasive wear of both the surfaces of the conveyors, packages and the eggshells themselves. This study aimed to determine such the coefficient of friction and wear intensity at various contacts. The friction and wear tests were conducted on two tribotesters and the results are shown in the article.

PL

Transport świeżych lub sproszkowanych jaj kurzych wykorzystuje przenośniki z elementami wykonanymi ze stali lub tworzyw sztucznych, a powierzchnie często pokryte teflonem. Różne formy jaj stykają się ze wspomnianymi powierzchniami i podlegają procesom tarcia między nimi. Opory tarcia powodują obciążenie urządzeń napędzających przenośniki oraz lokalny i tymczasowy wzrost temperatury w strefach styku i pozwala na zużycie ścierne powierzchni przenośników, pakietów i samych skorupek jaj. Badanie to miało na celu określenie takiego współczynnika tarcia i intensywności zużycia w różnych stykach. Testy tarcia i zużycia przeprowadzono na dwóch tribotesterach, a wyniki pokazano w artykule.

9

Wear performance of Ti-6Al-4 V titanium alloy through nano-doped lubricants

Etri Hamza E. L., Singla Anil Kumar, Özdemir Mehmet Tayyip, Korkmaz Mehmet Erdi, Demirsöz Recep, Gupta Munish Kumar, Krolczyk J. B., Ross Nimel Sworna

Archives of Civil and Mechanical Engineering

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2023

|

Vol. 23, no. 3

art. no. e147, 2023

EN

Titanium and its alloys are widely utilized in the biomedical sector, they still exhibit poor tribological properties and low wear resistance when employed against even weaker substances. The poor hardness, instability, high coefficient of friction, low load-carrying capacity, and insufficient resistance to not only abrasive but also adhesive wear are further disadvantages of titanium alloys. The focus of this investigation is on the tribological performance of Ti-6Al-4 V alloy in contact with WC carbide abrasive balls when subjected to nanodoped cooling and lubrication conditions. Tribological experiments were executed on Ti-6Al-4 V flat samples using a ball-on-flat tribometer in dry hybrid graphene/boron nitride combination nanoparticles (MQL, nano-3), nanographene with MQL (nano-1), and boron nitride with MQL (nano-2) conditions. After that, the most significant tribological characteristics were investigated, including volume loss, friction coefficient, wear rate, and micrographic structures. The outcomes also demonstrated that the hybrid nanoparticle situation experienced the least amount of volume loss.

10

Impact of friction coefficient variation on temperature field in rotary friction welding of metals – FEM study

Łukaszewicz Andrzej, Józwik Jerzy, Cybul Kamil

Applied Computer Science

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2023

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Vol. 19, no. 3

17--27

EN

A mathematical model is presented for investigating the temperature field caused by the rotary friction welding of dissimilar metals. For this purpose, an axisymmetric, nonlinear, boundary value problem of heat conduction is formulated with allowance for the frictional heating of two cylindrical specimens of finite length made of Al 6061 aluminium alloy and 304 stainless steel. The thermo-physical properties of materials change with increasing temperature. It was assumed that the coefficient of friction does not depend on the temperature. The mechanism of heat generation due to friction on the contact surface with the temperature field of samples is considered. The boundary problem of heat conduction was reduced to the set of nonlinear ordinary differential equations at time t relative to the values of temperature T at the finite elements nodes. The numerical solution of the problem was obtained with the inverse 2nd order differentiation method implemented in COMSOL FEM system (finite element method), with time step ∆t=0.1 (s). The influence of various values of friction coefficient is presented.

11

Surface Topography and Tribological Properties of Cutting Tool Coatings

Niemczewska-Wójcik Magdalena, Madej Monika

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no. 6

39--48

EN

The surface topography formed during the technological process has an influence on the wear characteristics and modifies the surface topography of friction components during the operation process, including cutting tools. It is therefore important to carry out research to find the best material and construction solutions to increase their durability and reliability. The research and analysis covered selected coatings (TiN, TiCN, TiAlN) applied to cutting tools for their anti-wear properties. The coatings were obtained through physical vapour deposition PVD. For the purpose of evaluating the tribological properties of the coatings, friction-wear tests were carried out in rotary motion on a ball-on-disc device (ball made of 100 Cr6 steel, discs made of SW7M steel coated with selected coatings) at a constant load (10N), under coolant lubrication conditions. Investigations of the surface topography before and after tribological tests were carried out on a confocal microscope. The friction coefficient and the amount of wear (wear track) of the coatings were shown to vary under the same operating conditions. The highest friction coefficient was obtained for the TiCN coating (0.199), while the lowest for the TiN coating (0.144) – the surface topography of the balls deteriorated (parameters Sq, Sz, Ssk, Sku increased in value). The highest linear wear (281.1 µm) was obtained for the TiAlN coating (the coating was torn halfway through the test), where the ball surface topography has improved (lowered values of parameters Sq, Sz, Ssk, Sku, Spd, Spc).

12

Effect of Water Absorption on Tribological Properties of Thermoplastics Matrix Composites Reinforced with Glass Fibres

Walczak Mariusz, Szala Mirosław, Pieniak Daniel

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no. 2

232--239

EN

The present work investigated the water absorption of thermoplastic matrix composites and their effect on tribological behaviour. Four thermoplastic composites were researched based on Polyamide 6 and Polyamide 66 matrix reinforced with glass fibres. The composites fabricated using the injection moulding technique were immersed in distilled water at room temperature for a water absorption test for 14 days. Dry sliding wear was conducted using a pin-on-disc trbiotester. The coefficient of friction (COF) and the wear rate (K) was determined. The sliding trace was analyzed using a scanning electron microscope (SEM) to reveal the sliding wear mechanism of composites. Studies have shown that polyamide PA6 based composites are less prone to absorb water than PA66 matrix. In addition, the composites richer in fibreglass exhibit lower water absorption. Tribological results indicated that polymer composites showed higher COF and K after water absorption testing. Mean COF and K were in the range of 0.071÷0.321 and 2.51∙10-6÷1.81∙10-4 mm3N-1m-1, respectively. Wear traces SEM analysis revealed that untreated samples are characterized by less intense abrasive and adhesive wear mode than the hydrated polymers. Besides, the degradation process took place primarily at the polymer matrix-fibreglass interfaces.

13

A Comparative Study of Tribological Behavior of Moglice and DK-6(PT) Composites

Pashechko Mykhailo, Ishchenko Аnatoliy, Radionenko Aleksandr, Kindrachuk Myroslav, Tisov Oleksandr

Advances in Science and Technology. Research Journal

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2022

|

Vol. 16, no. 1

149--157

EN

Authors have produced new polymer-based composite material DK-6(PT) for substitution of Moglice (Diamant) polymer. We manufactured and used sliding-friction test apparatus (pin-on-disc) capable of testing three specimens simultaneously, much reducing time for the test. The monitoring of the material curing process and the Shore hardness test indicate minor difference from reference material. Measurements were carried out during the curing period, since it is important to know change in this parameter over time. The wear test proved that DK-6(PT) composite in the long-time test has good wear resistance: over 80 km of the friction path, the wear loss of both materials is approximately the same. Furthermore, the friction factor of DK-6(PT) is 5–10% less than that of Moglice. Thus, the studied new polymeric composite may compete with well-known material Moglice and significantly cut the expenses for reconditioning of worn slide ways of metal working equipment.

14

Tribological properties of hardened surfaces constituted by various methods of mechanical processing

Zawadzki Paweł, Wierzbicka Natalia, Talar Rafał, Burysz Łukasz

Tribologia

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2021

|

nr 4

57--72

EN

The paper presents the results of experimental studies involving the determination of the coefficient of friction (COF) of surfaces constituted by selected machining methods. The tests were carried out on a Bruker UMT2 stand using a ball made of 100Cr6 steel with a hardness of 62 HRC and a disc made of X210CR12 (NC11LV) steel with a hardness of 62 ±0.4 HRC in dry conditions. During the research, wear products were not removed from the sliding path. The paper presents methods of producing samples and corresponding surface characteristics. Significant differences in topography characterised the surfaces obtained due to various machining. The COF values at the beginning of the study and the COF values occurring after a specific route in the reciprocating cycle reached similar values, despite the significant differences in the surface topography of the tested samples. Significant COF changes as a path function were observed for samples produced with different machining methods.

PL

Praca przedstawia wyniki badań doświadczalnych obejmujących wyznaczanie współczynnika tarcia (COF) powierzchni ukonstytuowanych wybranymi metodami obróbki mechanicznej. Badania przeprowadzono na stanowisku Bruker UMT2 bez stosowania medium smarującego w skojarzeniu kulki stalowej wykonanej ze stali 100Cr6 (ŁH15) o twardości 62 HRC i dysku stalowego wykonanego ze stali X210CR12 (NC11LV) o twardości 62 ±0.4 HRC. W trakcie prowadzenia badań produkty zużycia nie były usuwane ze strefy ruchu. W pracy przedstawiono sposoby wytworzenia próbek i odpowiednio charakterystyki powierzchni. Otrzymane w wyniku różnych sposobów obróbki powierzchnie charakteryzowały się dużymi różnicami ich topografii. Wartości COF występujące na początku badania i wartości COF występujące po przebyciu określonej drogi w cyklu posuwisto-zwrotnym osiągały zbliżone wartości pomimo znacznych odrębności topografii powierzchni badanych próbek. Zaobserwowano istotne różnice przebiegu zmian COF w funkcji drogi dla próbek wytworzonych odmiennymi metodami obróbki mechanicznej.

15

Tribological aspects of footwear safety

Przepiórka Jacek, Szczerek Marian, Sułek Marian Włodzimierz

Tribologia

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2021

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nr 4

37--44

EN

The key factor, from the consumer's point of view, during the use of footwear is the safety of use, characterized, among others, by the friction coefficient. A low coefficient of friction can cause skidding, which is very dangerous for the elderly, people with motor apparatus injuries, those with impaired motor skills, and those with a high body BMI index. Fall injuries result in hospitalization, generating high costs of treatment and compensation. The article presents the results of tribological tests of typical footwear sole materials in combination with selected base materials depending on the load on the friction junction, the initial temperature, and the presence of water. The combination of the friction coefficient with the safety of footwear use for typical operating conditions is a new approach to the requirements of ergonomics and increasing comfort while walking.

PL

Kluczowym czynnikiem, z punktu widzenia konsumenta, podczas eksploatacji obuwia jest bezpieczeństwo użytkowania, charakteryzowane między innymi współczynnikiem tarcia. Mały współczynnik tarcia może powodować poślizg, który jest bardzo niebezpieczny dla osób starszych, osoby z urazami aparatu ruch, z upośledzoną motoryką oraz z wysokim indeksem BMI ciała. Urazy powstałe podczas upadku są powodem hospitalizacji generującej wysokie koszty leczenia oraz odszkodowania. W artykule przedstawiono wyniki badań tribologicznych typowych obuwniczych materiałów spodowych w skojarzeniu z wybranymi materiałami podłożowymi w zależności od obciążenia węzła tarcia, temperatury początkowej oraz obecności wody. Powiązanie współczynnika tarcia z bezpieczeństwem użytkowania obuwia dla typowych warunków eksploatacji stanowi nowe podejście do wymogów ergonomii i zwiększenia komfortu podczas chodzenia.

16

An Analysis of the Influence of Carbon Nanoparticles Additive on Selected Properties of Lubricating Oils

Frycz Marcin, Labuda Mateusz

Tribologia

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2021

|

nr 2

7--20

EN

This paper presents the results of an analysis of the influence of the addition of various types of carbon nanoparticles on selected essential physical and operational properties of lubricating oils. Two selected oils, i.e. the mineral base oil without additives and the typical marine lubricating circulating oil Marinol RG 1240, were modified with the addition of shungite nanoparticles, graphite nanotubes, and C60 fullerenes. The mass fraction of modifiers was 0.2% wt for each of the additives. As part of the experimental tests, measurements were made of the impact of the above-mentioned modifiers on the change in the value of the ignition temperature of oils, the effect on the changes in the value of the dynamic viscosity coefficient in the aspect of changes of temperature and shear rate, as well as the impact on the changes in the friction coefficient and the size of the wear size scar. These tests were carried out on an EraFlash automatic apparatus for determining ignition temperature using the closed cup method, with a Haake Mars III research rheometer, and a T-02U tribometer with a four-ball head.

PL

W niniejszej pracy zaprezentowane zostały wyniki analizy wpływu dodatku różnego rodzaju nanocząstek węgla na wybrane istotne właściwości fizyczne i eksploatacyjne olejów smarowych. Dwa wybrane oleje, tj. mineralny olej bazowy nie zawierający dodatków uszlachetniających oraz typowy morski smarowy olej obiegowy Marinol RG 1240, zostały zmodyfikowane dodatkiem nanocząsteczek szungitu, nanorurek grafitu oraz fullerenów C60. Udział masowy modyfikatorów wynosił 0,2% wt w przypadku każdego z dodatków. W ramach badań eksperymentalnych dokonano pomiarów wpływu wymienionych modyfikatorów na zmianę wartości temperatury zapłonu olejów, wpływu na zmiany wartości dynamicznego współczynnika lepkości w aspekcie zmian temperaturowych, jak również szybkości ścinania, a także wpływu na zmiany współczynnika tarcia i wielkości śladu zużycia. Badania te zostały przeprowadzone odpowiednio na automatycznym aparacie do wyznaczania temperatury zapłonu EraFlash metodą tygla zamkniętego, reometrze badawczym Haake Mars III oraz tribometrze z głowicą czterokulową T-02U. Uzyskane w badaniach eksperymentalnych wyniki zostały poddane analizie, zostały również poczynione obserwacje oraz wyciągnięte wnioski dotyczące wpływu nanomodyfikatorów węgla na wybrane właściwości olejów w szczególności w kontekście ich potencjalnego zastosowania w olejach smarujących.

17

Influence of different hard-facing procedures on quality of surfaces of regenerated gears

Nikolić Ružica R., Marković Svetislav, Arsić Dušan, Lazić Vukić, Hadzima Branislav, Ulewicz Robert

Production Engineering Archives

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2021

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Vol. 27, Iss. 4

257--264

EN

During the process of regeneration of machine parts, certain phenomena occur that have a significant impact on the loss of their working ability. Hereditary properties are expressed by the interdependence of geometric and physical-mechanical-metallurgical parameters of gear teeth created during the technological operations of regeneration of worn teeth by hard-facing. The influence of the type of additional material (electrodes and their combinations) on the tribological characteristics of welded gear teeth was considered, whereby the so-called hard additional materials were applied. Those are the additional materials that give the required surface hardness of the teeth without subsequent thermal or thermochemical treatment. This research did not involve the regeneration of specific worn gears removed from machine systems, but the new gears were made, which were then damaged and then regenerated by hard-facing using the shielded metal arc welding (SMAW) procedure. Thus, all the tested gears were made of the same material, belonged to one batch and were machined on the same machines with the same machining regimes. The tests were performed on samples made of 20MnCr5 steel for cementation, on a tribometer by the “block on disc” method, which was designed to simulate the operating conditions of coupled teeth of concrete gears in the exploitation conditions. Based on the conducted tribological tests, the average coefficients of friction and topography of the surfaces were determined by measuring the wear trace and it was defined which additional materials give the best tribological characteristics of the surfaces of gears regenerated by hard-facing.

18

Enhancement of turbulent airflow and heat transfer through a rectangular microchannel with different types of baffles

Saha Sandip, Raut Santanu, Das Apurba Narayan

Journal of Applied Mathematics and Computational Mechanics

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2021

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Vol. 20, nr 3

41--52

EN

The objective of this work is to discuss the turbulent air hydro-thermal phenomena over a rectangular microchannel with different types of baffle (rectangular, triangular, and trapezoidal) mounted on both the walls of the microchannel. The finite volume method with the second order upwind scheme has been utilized to discretize the governing equations and to study the turbulent airflow characteristics; the SST k-ꞷ turbulence model has been adopted. For nine different cases, the different characteristics of fluid flow phenomena and thermal behaviour with the variations in the Reynolds number ranging from [5,000-25,000] and for three different values of inter baffle spacing have been studied in this manuscript. Due to the presence of baffle, it is revealed that the vortex arises on the upper wall and the thermal phenomena enhances with the decrease in inter baffle spacing.

19

Identification of the operating parameters of the friction drum drive in industrial conditions

Kulinowski Piotr, Kasza Piotr, Zarzycki Jacek

Eksploatacja i Niezawodność

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2021

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Vol. 23, no. 1

94--102

EN

The publication presents the results of measurements of the operating parameters of the drum drive of a belt conveyor operating in a copper ore mine. The laboratory and industrial tests of belt conveyor components so far have largely focused on idler sets, the belt and the conveyor route. The authors of the publication notice that the subject literature lacks information on research into the coefficient of friction between the belt and the drum in an industrial facility under real conditions, which may imply that the phenomenon of driving force transmission from the drum surface to the belt has not been thoroughly explored. The investigations described in the publication were aimed at determining the kinetic coefficient of friction between the conveyor belt and the lining of the drive drum under operating conditions. In the first part of the study, preliminary laboratory tests were carried out, whereas in the second part of the study, a mobile, non-invasive measurement system was applied, which allowed for recording the kinematic and dynamic parameters of the conveyor’s operation. During the several dozen minutes of the conveyor’s operation, there were several start-ups and brakings as well as periods of steady operation under variable load on the material handled. The non-typical planned sequence of switching on the drive motors caused a temporary slip of the belt on the drive drum surface during one of the start-ups. The recorded parameters of the conveyor operation enabled determining the operational limit value of the friction coefficient between the belt and the lining of the drive drum.

20

Influence of the Structure of Seersucker Woven Fabrics on their Friction Properties

Frącczak Łukasz, Matusiak Małgorzata

Autex Research Journal

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2021

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Vol. 21, no. 1

85--91

EN

Friction is defined as a force resisting a relative motion between two bodies in contact. The friction of a fabric on itself or on another fabric influences significantly a fabric’s performance and user’s utility comfort, especially the so-called sensorial comfort. Generally, the coefficient of friction is determined for a given pair of materials. The aim of the present work was to investigate the influence of the structure of the seersucker woven fabrics on their frictional properties. Three variants of the seersucker woven fabrics of different repeat of the seersucker effect were the objects of the investigations. Three measuring elements were applied: made of aluminum and steel and covered with silicone. The obtained results confirmed the influence of the pattern of the seersucker effect on the values of friction coefficient. It was also stated that there are differences between the friction coefficients measured in the warp and weft directions of the seersucker woven fabrics. Values of friction coefficient between the seersucker woven fabrics and measuring elements were the highest for the measuring element covered by silicone. These values were several times higher than the values of friction coefficient measured using the measuring elements made of aluminum and steel.