Wyniki wyszukiwania - BazTech

1

Porównanie metod oceny tekstury nawierzchni lotniskowych na podstawie pomiarów różnymi profilometrami

Wasilewska Marta, Wesołowski Mariusz, Blacha Krzysztof

Materiały Budowlane

|

2024

|

nr 7

35--41

PL

W artykule przedstawiono analizę porównawczą wyników badania parametru MPD (Mean Profile Depth) z wykorzystaniem profilometru dynamicznego (Skaner 2D/3D scan CHS (CONTROLHIGH-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.

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 TrackMeter; 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.

2

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

|

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.

3

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

|

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.

4

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

|

2023

|

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.

5

Surface Topography and Tribological Properties of Cutting Tool Coatings

Niemczewska-Wójcik Magdalena, Madej Monika

Advances in Science and Technology. Research Journal

|

2023

|

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).

6

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

|

2022

|

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.

7

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

|

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.

8

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

Zawadzki Paweł, Wierzbicka Natalia, Talar Rafał, Burysz Łukasz

Tribologia

|

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.

9

Tribological aspects of footwear safety

Przepiórka Jacek, Szczerek Marian, Sułek Marian Włodzimierz

Tribologia

|

2021

|

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.

10

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

Frycz Marcin, Labuda Mateusz

Tribologia

|

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.

11

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

|

2021

|

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.

12

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

|

2021

|

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.

13

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

Kulinowski Piotr, Kasza Piotr, Zarzycki Jacek

Eksploatacja i Niezawodność

|

2021

|

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.

14

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

Frącczak Łukasz, Matusiak Małgorzata

Autex Research Journal

|

2021

|

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.

15

Laboratory Device Detecting the Magnitude of the Static Friction Coefficient of Brake Lining

Hrabovský Leopold, Hrbáč Roman

Advances in Science and Technology. Research Journal

|

2021

|

Vol. 15, no 2

191--197

EN

The paper describes the design of laboratory equipment, which was created for verification and determination of the value of the static coefficient of friction in the contact surfaces of the brake lining and the brake drum of the drum brake with external shoes by experimental procedure. Suppliers of brake linings state values of the friction coefficients which correspond to different operating temperatures, but do not state the values of the friction coefficient of the respective brake lining with regard to the state of contamination of the contact surfaces. In practice, brake contact surfaces are exposed to moisture, dust, lubricants and oils, and these weather and operational influences significantly affect the value of the coefficient of friction. The results of laboratory tests performed with two types of brake linings (commonly used in practice) (fabric, hardened rubber) show that the coefficient of friction of a given brake lining is strongly influenced by the state of contamination of the contact surfaces.

16

Tribological Characteristics of Polyurethanes Used for the Soles of Footwear

Przepiórka Jacek, Szczerek Marian, Sułek Marian Włodzimierz

Tribologia

|

2020

|

nr 6

71--75

EN

The inability to take into account the type of base material (floor, pavement, soil), as well as the inability to take into account the variable friction conditions – load, intermediary medium (water, loose abrasive, sand or other soil particles), sliding velocity, and ambient temperature – is a significant limitation the use of friction methods and devices used so far in the footwear industry to precisely anticipate the behavior of the bottom materials in the actual operating conditions of the footwear. These limitations prompted the authors to adapt a tribological tester for this purpose, used in the area of construction and operation of machines and material engineering. A research methodology was developed and, in order to verify it, measurements of the coefficient of friction and wear of polyurethane used for shoe soles in combination with a raw and varnished wooden substrate were carried out. The obtained test results are characterized by diversity, which proves the high research resolution of the developed method. It allows determining the coefficient of friction of associations influencing the slip of the footwear and the wear and tear that determines the length of use of the footwear.

PL

Brak możliwości uwzględnienia rodzaju materiału podłoża (posadzka, podłoga, nawierzchnia, grunt), jak też brak możliwości uwzględnienia zmiennych warunków tarcia – obciążenia, medium pośredniczącego (woda, luźne ścierniwo, piasek lub inne cząstki gruntu), prędkości poślizgu, temperatury otoczenia stanowi istotne ograniczenie wykorzystania metod i urządzeń tarciowych stosowanych dotychczas w przemyśle obuwniczym do precyzyjnego antycypowania zachowania się materiałów spodowych w rzeczywistych warunkach eksploatacji obuwia. Ograniczenia te skłoniły autorów do przystosowania do tego celu testera tribologicznego, wykorzystywanego w obszarze budowy i eksploatacji maszyn oraz inżynierii materiałowej. Opracowano metodykę badawczą oraz w celu jej weryfikacji przeprowadzono pomiary współczynnika tarcia i zużycia poliuretanu stosowanego na podeszwy obuwia w skojarzeniu z podłożem drewnianym surowym i lakierowanym. Otrzymane wyniki badań charakteryzują się zróżnicowaniem świadczącym o dużej rozdzielczości badawczej opracowanej metody. Pozwala ona określać współczynnik tarcia skojarzeń mający wpływ na poślizg obuwia oraz zużycie decydujące o długości eksploatacji obuwia.

17

The Influence of an Operating Conditions on the Friction Coefficient in Transportation Machines Drives

Kasza Piotr, Kulinowski Piotr, Zarzycki Jacek

New Trends in Production Engineering

|

2020

|

Vol. 3, Iss. 1

294--302

EN

The publication presents the construction of the station for testing the friction coefficient under high pressure and low slip velocity values. These conditions of cooperation of friction pairs occur in the drives of transport machines such as belt conveyors and suspended monorails. The value of the friction coefficient, depending on the operating conditions such as moisture and rock or coal dust pollution, has a significant impact on the correct and efficient operation of such drives. The features of the station allow mapping the operating conditions on a laboratory scale. As part of the research, appropriate friction samples made of rubber or polyurethane were prepared. Referring to the conditions of conveyor operation and conditions of contact of the conveyor belt with the drive drum, the values of unit pressures and values of slip speed occurring in the drum drive of the belt conveyor were determined. A series of laboratory tests were carried out for the friction pair rubber drum lining – conveyor belt cover. The tests were carried out for four different states of friction vapor surfaces, namely for dry and wet samples, as well as for samples in clean or contaminated with stone dust. As a result of the tests, the values of friction coefficients for various surface states were determined, which will be valuable information for designers of friction drive systems of transport devices.

18

Jak obiektywnie ocenić odporność posadzki na poślizg?

Sudoł Ewa

Inżynier Budownictwa

|

2020

|

nr 10

58--62

19

Współczynnik tarcia nawierzchni – analiza zagadnień, urządzenia pomiarowe.

Łądkiewicz-Krochmal Katarzyna

Drogownictwo

|

2020

|

nr 2

35--44

PL

Jedną z cech nawierzchni drogowej są jej właściwości przeciwpoślizgowe. Opisują one przyczepność pomiędzy nawierzchnią a oponą pojazdu. Podstawowym parametrem charakteryzującym w sposób sformalizowany właściwości przeciwpoślizgowe nawierzchni jest bezwymiarowy współczynnik tarcia. Jego pomiar opiera się na symulacji wystąpienia warunku poślizgu na mokrej nawierzchni, jako najbardziej niekorzystnego z punktu widzenia przyczepności kół pojazdu. Jest to o tyle istotne, że niewłaściwe właściwości przeciwpoślizgowe mają bezpośredni związek m.in. z długością drogi hamowania. W artykule szczegółowo zdefiniowano oraz omówiono pojęcia „właściwości przeciwpoślizgowych” i „współczynnika tarcia” wraz z wyjaśnieniem mechanizmu tarcia oraz podaniem czynników wpływających na wielkość tego zjawiska. Ponadto przedstawiono również metody i urządzenia wykorzystywane do wykonywania pomiarów.

EN

One of the features of road pavement are its skid resistance properties. They describe adhesion between the road surface and the vehicle’s tyre. The basic parameter characterizing skid resistance properties of the pavement in a formalized way is the dimensionless coefficient of friction. Its measurement is based on simulation of the wet slip condition as the most unfavourable condition for wheel adhesion of the vehicle. This is all the more important because inappropriate skid resistance is directly related to, among others with the length of the braking distance. The paper defines and discusses in detail the notions of “skid resistance properties” and “friction coefficient”, together with an explanation of the friction mechanism and the factors influencing the size of this phenomenon. In addition, the methods and dequipment used to take measurements are also presented.

20

Characterization of Fabric-to-Fabric Friction: Application to Medical Compression Bandages

Chassagne Fanette, Benoist Emilie, Badel Pierre, Convert Reynald, Schacher Laurence, Molimard Jérôme

Autex Research Journal

|

2020

|

Vol. 20, no. 2

220--227

EN

Fabric-to-fabric friction is involved in the action mechanism of medical compression devices such as compression bandages or lumbar belts. To better understand the action of such devices, it is essential to characterize, in their use conditions (mainly pressure and stretch), the frictional properties of the fabrics they are composed of. A characterization method of fabric-to-fabric friction was developed. This method was based on the customization of the fourth instrument of the Kawabata Evaluation System, initially designed for fabric roughness and friction characterization. A friction contactor was developed so that the stretch of the fabric and the applied load can vary to replicate the use conditions. This methodology was implemented to measure the friction coefficient of several medical compression bandages. In the ranges of pressure and bandage stretch investigated in the study, bandage-to-bandage friction coefficient showed very little variation. This simple and reliable method, which was tested for commercially available medical compression bandages, could be used for other medical compression fabrics.