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EN
Journal bearings are the most common type of bearings in which a shaft freely rotates in a metallic sleeve. They find a lot of applications in industry, especially where extremely high loads are involved. Proper analysis of the various bearing faults and predicting the modes of failure beforehand are Essentials to increase the working life of the bearing. In the current study, the vibration data of a journal Bering in the healthy condition and in five different fault conditions are collected. A feature extraction metod is employed to classify the different fault conditions. Automatic fault classification is performed using artificial neural networks (ANN). As the probability of a correct prediction goes down for a higher number of faults in ANN, the method is made more robust by incorporating deep neural networks (DNN) with the help of autoencoders. Training was done using the scaled conjugate gradient algorithm and the performance was calculated by the cross entropy method. Due to the increased number of hidden layers in DNN, it is possible to achieve a high efficiency of 100% with the feature extraction method.
EN
In this paper, the presented issue concerns hydrodynamic lubrication of the journal bearings with the oil of non-Newtonian properties. For the analysis of the hydrodynamic lubrication, a constitutive model of the third order was assumed. The assumed model consist of a Newtonian part –pI+nA1&enspand non-Newtonian part &beta3&ensp tr(A12)A1. The Main part of this paper concerns transformation, nondimensionalization, and an estimation of order of magnitude of the equation, which describes the apparent viscosity. Apparent viscosity describes changes of the dynamic viscosity with shear rate. In this way prepared model of apparent viscosity is used in momentum equations. This equations are integrated in order to designate components of the velocity vector. By substitution of the proper boundary conditions, modified Reynolds type equation is obtained. A further stage of the research will be proceeding of the numerical calculations of the hydrodynamic pressure distribution followed by the designation of the carrying capacity, friction force and friction coefficient while taking changes of the viscosity from shear rate into account (apparent viscosity).
PL
Prezentowana w artykule tematyka dotyczy problemu hydrodynamicznego smarowania poprzecznych łożysk ślizgowych olejem o właściwościach nienewtonowskich. Do analizy hydrodynamicznego smarowania przyjęto część modelu konstytutywnego trzeciego rzędu. Przyjęty model składa się z części opisującej właściwości newtonowskie –pI+nA1&ensporaz części opisującej właściwości nienewtonowskie &beta3&ensp tr(A12)A1. Zasadnicza część pracy dotyczy przekształcenia, ubezwymiarowienia oraz oszacowaniu rzędu wielkości równania opisującego lepkość pozorną, w której uwzględnia się zmiany lepkości dynamicznej od szybkość ścinania. Tak opracowany model lepkości pozornej podstawiany jest do równań pędu i ciągłości strugi. Równania te są całkowane w celu wyznaczenia składowych wektora prędkości. Przy nałożeniu odpowiednich warunków brzegowych uzyskuje się również zmodyfikowane równanie typu Reynoldsa. Dalszym etapem badań będzie wykonanie obliczeń numerycznych rozkładu ciśnienia hydrodynamicznego a następnie wyznaczeniu siły nośnej, siły tarcia i współczynnika tarcia z uwzględnieniem zmian lepkości od szybkości ścinania (lepkości pozornej).
EN
Journal bearings are widely used to support the shafts in industrial machinery involving heavy loads, such as compressors, turbines and centrifugal pumps. The major problem that could arise in journal bearings is catastrophic failure due to corrosion or erosion and fatigue, which results in economic loss and creates major safety risks. Thus, it is necessary to provide suitable condition monitoring technique to detect and diagnose failures, and achieve cost savings to the industry. Therefore, this paper focuses on fault diagnosis on journal bearing using Debauchies Wavelet-02 (DB-02). Nowadays, wavelet transformation is one of the most popular technique of the time-frequency-transformations. An experimental setup was used to diagnose the faults in the journal bearing. The accelerometer is used to collect vibration data, from the journal bearing in the form of time domain. This was then used as input for a MATLAB code that could plot the time domain signal. This signal was then decomposed based on the wavelet transform. The fast Fourier transform is then used to obtain the frequency domain, which gives us the frequency having the highest amplitude. To diagnose the faults various operating conditions are used in the journal bearing such as Full oil, half loose, half oil, fault 1, fault 2, fault 3 and full loose. Then the Artificial Neural Networks (ANN) is used to classify faults. The network is trained based on data already collected and then it is tested based on random data points. ANN was able to classify the faults with the classification rate of 85.7%. Thus, the test process for unseen vibration data of the trained ANN combined with ideal output target values indicates high success rate for automated bearing fault detection.
EN
The article presents the results of a sliding bearing with a helical groove on a journal. The studies included wear tests with contaminated lubrication oil and computer simulation of oil flow based on which the load capa city of a bearing was determined. The 7 bearings with different variants of helical grooves on journal bearings and classical bearings were studied. It was found that the helical groove on the journal makes it possibile to significantly reduce the wear of the bearing in the case of oil contamination with hard particles. It was also shown that the groove on the journal ensures an effective reduction in wear and does not result in a significant reduction of load capacity.
PL
W artykule przedstawiono wyniki badań łożyska ślizgowego ze śrubowym rowkiem na czopie. Przeprowadzone badania obejmowały testy zużyciowe przy smarowaniu olejem zanieczyszczonym oraz komputerową symulację przepływu, na podstawie której wyznaczono nośność łożyska. Przebadano 7 łożyskowań z różnymi wariantami śrubowego rowka na czopie oraz łożysko klasyczne. Stwierdzono, że śrubowy rowek na czopie daje możliwość znacznego zmniejszenia zużycia układu łożyskowego w przypadku zanieczyszczenia oleju twardymi cząstkami. Wykazano również, że rowek na czopie zapewniający efektywne zmniejszenie zużycia nie skutkuje znaczącym zmniejszeniem nośności łożyska.
EN
A static friction during a slide bearing’s start-up appears to be a complicated process. To deal with the phenomenon, the author uses a molecular-mechanical theory of friction. This paper reports the results that show the influence of a surface geometric structure of a journal on a static friction coefficient, a frictional moment and tangential stresses on a bushing surface. In analysis of results, it can be noticed that machining selection and the accuracy of a journal surface have the significant impact on bearing system during its start-up.
PL
Zjawisko tarcia spoczynkowego podczas rozruchu łożysk ślizgowych jest procesem złożonym. Do analizy zjawisk przyjęto molekularno-mechaniczną teorię tarcia. W pracy przedstawiono wyniki badań opisujące wpływ struktury geometrycznej powierzchni czopa na współczynnik tarcia spoczynkowego, moment tarcia i naprężenia styczne na powierzchni panewki. W analizie wyników badań wykazano, że rodzaj i dokładność obróbki powierzchni czopa w istotny sposób wpływa na właściwości węzła łożyskowego podczas jego rozruchu.
EN
This research work describes a method for the determination of the static friction factor in slide bearings. To determine tangential stresses distribution in a real area of a contact the author uses a molecular-mechanical theory of friction. In this theory, the total frictional force is equal to the sum of system of forces: molecular and material resistance to the deformation of bodies' surface coating. To design a model the following assumptions are accepted: a journal surface is rough, and a bushing surface is perfectly smooth. The results are represented in the form of graph which shows an influence of the contact angle of a journal surface and a bushing on a load, a frictional moment, tangential stresses, and a friction coefficient.
PL
W pracy przedstawiono metodę wyznaczania współczynnika tarcia spoczynkowego w łożyskach ślizgowych. Do określenia rozkładu naprężeń stycznych w rzeczywistym obszarze styku przyjęto molekularno-mechaniczną teorię tarcia. W teorii tej całkowita siła tarcia jest równa sumie sił składowych: molekularnej i odporności materiałów na deformowanie warstwy powierzchniowej ciał. W budowie modelu przyjęto m.in. założenia: powierzchnia czopa jest chropowata, natomiast powierzchnia panewki jest idealnie gładka. Wyniki obliczeń, wpływ kąta kontaktu powierzchni czopa i panewki na obciążenie, moment tarcia, naprężenia styczne, współczynnik tarcia przedstawiono w formie wykresów.
7
Content available remote Badanie zużycia panewki w poprzecznym łożysku ślizgowym
PL
W artykule przedstawiono metodę, która pozwala wyznaczyć profil zużycia panewki łożyska ślizgowego. Metoda ta polega na określeniu zarysu okrągłości powierzchni roboczej łożyska ślizgowego. Profil zużycia panewki ustalono wyznaczając położenie łuku zużycia oraz lokalnych zmian promienia panewki na łuku zużycia. W artykule przedstawiono przykłady zużycia panewek po różnych okresach eksploatacji dla dwóch stopów łożyskowych.
EN
This paper presents the method that allows determining of the wear of operating surface of radial bearing sleeve. The wear measurement consists in determination of the roundness profile deviation of sleeve internal diameter. The developed method allows determining of wear profile by means of its orientation, the length of wear arc as well as the local variation of sleeve radius on the wear arc. The examples of sleeve wear after different periods of exploitation wear presented, too.
8
Content available remote The effect of helical groove geometry on journal abrasive wear
EN
The article presents an experimental study of slide bearings operating in lubricant contaminated by Al2O3 abrasive particles. The aim of this work was the comparison of wear resistance of slide bearings with different surface geometry on the journal. It was found that helical groove on the journal significantly reduced wear of sliding pairs. The results of experiments showed that groove cross section area and helical groove lead affected abrasive wear. Valuable results concerning the sleeve wear reduction were obtained with respect to bearings with textured journals.
EN
The article presents the results of investigations into the wear of slide bearings with a non-typical bearing journal. Pairs made up of elements of different hardness operating together and journals of different design were studied. The possibility of reducing the wear due to contaminant hard particles in the oil by a change in the journal design was pointed out. The reduced material loss in this situation is probably due to contaminants being effectively removed from the abrasive contact area owing to the belts of soft material and the grooves on the surface of the journal. It was also found that the modified journal reduces wear in concentrated linear contact. This is probably due to effective, wear reducing boundary layers which form during friction owing to the presence of a modifying material.
10
Content available remote Bexperimental Investigation into Tribopairs Journal Sleeve of Journal Bearing
EN
This paper presents the results of plain journal bearings with the operating surface covered by white metal bearing alloys: tin and lead operating with steel journal and bush poured by bronze and nitrosulfonized. It also presents preliminary studies of bearing set: hardened steel journal covered with a layer of nano-composite nc-WC/aC: H - bush of bearing metal as lead alloy. The effect of wear on the tribological characteristics of the bearing was investigated. During the tests a continuous identification of friction conditions was monitored in the bearing. The wear was determined by a method based on the measurement of the roundness of bearing operating surface as well as on the traditional way by weight.
PL
W artykule przedstawiono wyniki badań zużycia łożyskowań ślizgowych smarowanych olejem zanieczyszczonym tlenkiem glinu. Przebadano sześć skojarzeń różniących się twardością współpracujących elementów oraz konstrukcją czopa. Wykazano możliwość zmniejszenia zużycia wywołanego zawartymi w oleju twardymi zanieczyszczeniami poprzez zmianę konstrukcji czopa. Przeprowadzono ponadto analizę porównawczą intensywności zużycia dla testowanych skojarzeń ślizgowych.
EN
Results of tribological wear investigations concerning sliding bearings with six different journals in the presence of an oil abrasive contaminant are presented in the paper. The investigated variants are as follows: – Variant 1 – journal made from C45 steel (hardness 86 HB) mating with sleeve made from MB 50 alloy (79% Al, 20% Sn, 1% Cu, hardness žHV0,1 = 600 MPa), – Variant 2 – journal made from heat-treated 34CrNiMo6 steel (hardness 34 HRC) mating with a sleeve made from MB 50 alloy, – Variant 3 – journal made from heat-treated 34CrNiMo6 steel (hardness 34 HRC) with a two- component surface layer (steel-copper) mating with a sleeve made from MB 50 alloy, – Variant 4 – journal made from heat-treated 34CrNiMo6 steel (hardness 34 HRC) with two- component surface layer (steel-copper) mating with a sleeve made from heat-treated C45 steel (hardness 30 HRC), – Variant 5 – journal made from heat-treated 42CrMo4 steel (hardness 52 HRC) mating with a sleeve made from MB 50 alloy, and – Variant 6 – journal made from heat-treated 42CrMo4 steel (hardness 52 HRC) with a helical groove mating with a sleeve made from MB 50 alloy. The lubricating agent was SAE 40 oil contaminated with Al2O3 particles. Wear volumetric intensity (Iv) for all investigated bearings, as a quotient of volumetric wear and friction path, was calculated. The least tribological wear (Iv = 0.85 mm3/km) was stated for Variant 4. The research indicates that both of the investigated journal modifications resulted in a wear intensity decrease (for variant 3 Iv = 2.73 mm3/km, for variant 6 Iv = 1.21 mm3/km) in the case of an abrasive contaminant in the oil.
12
Content available Surface topography of slide journal bearings
EN
In this article the measurements results of surface topography of different types of slide bearings sleeves have been presented. The research has been conducted with the use of atomic force microscope (AFM). The results of measurements of surface topography were presented in the form of surface topography maps, three-dimensional graphs and some examples of selected cross-sections of investigated surface in the form of profile graphs. Measurements of surface topography were made for thin-walled sleeves of slide journal bearings covered with PTFE, POM, bronze and white metal layers. Operated and new sleeves have been considered with the use of Atomic Force Microscope NT-206produced in MTM in Minsk, Republic of Belarus [2]. Atomic Force Microscope NT-206 provides information for samples with maximum roughness value plus or minus 1 mi m. Max. field in one scanning process is up to 32)um x 32mi m. Measurements were preceded with resolution 256x256points. Presented in the work results of surface topography measurements also include the calculated values of average deviation profile Ra and Rq and the value of fixed distance between the lowest and highest inequality. The application SurfaceXplorer was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graph of height distribution. The comparison of received data will allow verifying type and amount of surface wear of discussed journal micro-bearings parts in micro and nanoscale and will help to design surface layers with improved tribological properties.
EN
Present paper shows the results of numerical solution Reynolds equation for laminar, steady oil flow in slide bearing gap. Lubrication oil is fluid with micropolar structure. Materials engineering and tribology development helps to introduce oils with the compound structure (together with micropolar structure) as a lubricating factors. Properties of oil lubrication as of liquid with micropolar structure in comparison with Newtonian liquid, characterized are in respect of dynamic viscosity additionally dynamic couple viscosity and three dynamic rotation viscosity. Under regard of build structural element of liquid characterized is additionally microinertia coefficient. In modelling properties and structures of micropolar liquid one introduced dimensionless parameter with in terminal chance conversion micropolar liquid to Newtonian liquid. The results shown on diagrams of hydrodynamic pressure, velocity and velocity of microrotation distribution in dimensionless form in dependence on coupling number N2 and characteristic dimensionless length of micropolar fluid A1. Differences were showed on graphs in the schedule of the circumferential velocity oils after the height of the gap in the flow of the micropolar and Newtonian liquid. In presented flow, the influence of lubricating fluid inertia force and the external elementary body force field were omitted. Presented calculations are limited to isothermal models of bearing with infinite length.
PL
Celem zaprezentowanych w artykule analiz było określenie wpływu śrubowego rowka na czopie na nośność poprzecznego łożyska ślizgowego. W efekcie przeprowadzonych badań zaproponowano dwa wskaźniki, za pomocą których można dokonać prognozy wpływu geometrii rowka i szczeliny smarowej na nośność. Artykuł zawiera również zestawienie wartości wskaźników oraz nośności wyznaczonych dla konkretnych przykładów łożysk.
EN
Investigations concerning the influence of a helical groove on the load carrying capacity of hydrodynamic plain bearing are presented in the paper. Two indicators were developed as a result of investigations. The first indicator is a quotient of groove volume and bearing interspace volume. It has been stated that, if the value of this indicator does not exceed 0.5% the load carrying capacity of the grooved bearing is above 90% that of classical bearing. The second indicator is a quotient of the groove’s cross-section area and bearing interspace cross-section area in the place of minimum bearing interspace thickness. It has been stated, that if the value of this indicator does nott exceed 2% load carrying capacity, the decrease in load capacity of the grooved bearing is less than 10% in relation to a bearing with smooth journal. The above mentioned dependencies are initial and should be studied in additional investigations.
15
EN
This paper shows results of numerical solutions an modified Reynolds equations for laminar unsteady oil flow in slide journal bearing gap. Laminar unsteady oil flow is performed during periodic and unperiodic perturbations of bearing load or is caused by the changes of gap height in time. During modelling crossbar bearing operations in combustion engines, bearing movement perturbations from engine vertical vibrations causes velocity flow perturbations of lubricating oil on the shaft in the circumferential direction. This solution example apply to isothermal bearing model with infinity length. Lubricating oil used in this model has Newtonian properties and constant dynamic viscosity. Results are presented in the dimensionless hydrodynamic pressure and tangential tension distribution diagrams. Diagrams also presents capacity and friction force change during the time of velocity perturbations. Received solutions were compared with the solution received by the stationary lubrication flow in the slide journal bearing, which were made with the same parameter assumption by constant dynamic oil viscosity. Isothermal bearing model is similar to friction node model by steady-state heat load conditions. Described effect can be used as on example of modeling the bearing friction node operations in reciprocating movement during exploitation of engines and machines.
EN
Present paper shows the results of numerical solution Reynolds equation for laminar, steady oil flow in slide bearing gap. Lubrication oil is fluid with micropolar structure. Materials engineering and tribology development helps to introduce oils with the compound structure (together with micropolar structure) as a lubricating factors. Properties of oil lubrication as of liquid with micropolar structure in comparison with Newtonian liquid, characterized are in respect of dynamic viscosity additionally dynamic couple viscosity and three dynamic rotation viscosity. Under regard of build structural element of liquid characterized is additionally microinertia coefficient. In modeling properties and structures of micropolar liquid one introduced dimensionless parameter with in terminal chance conversion micropolar liquid to Newtonian liquid. The results shown on diagrams of hydrodynamic pressure, velocity and velocity of microrotation distribution in dimensionless form in dependence on coupling number N2 and characteristic dimensionless length of micropolar fluid Ë1. Differences were showed on graphs in the schedule of the circumferential velocity oils after the height of the gap in the flow of the micropolar and Newtonian liquid. In presented flow, the influence of lubricating fluid inertia force and the external elementary body force field were omit. Presented calculations are limited to isothermal models of bearing with infinite length.
EN
This paper shows results of numerical solutions modifled Reynolds equations for laminar unsteady oil flow in slide Journal bearing gap. Laminar unsteady oil flow is performed during periodic and unperiodic perturbations of bearing load or is caused by the changes of gap height in time. During modelling crossbar bearing operations in combustion engines, bearing movement perturbations from engine vertical vibrations causes velocity flow perturbations of lubricating oil on the bearing race and on the bearing slider in the circumferential direction. Above perturbations occur mostly during the starting and stopping of machine. This solution example applies to isothermal bearing model with infinity length. Lubricating oil used in this model has Newtonian properties and constant dynamic viscosity. Results are presented in the dimensionless hydrodynamic pressure and tangential tension distribution diagrams. Diagrams also presents capacity and friction force change during the time ofvelocity perturbations. Received solutions were compared with the solution received by the stationary lubrication flow in the slide Journal bearing, which were made with the same parameter assumption by constant dynamie oil viscosity. Isothermal bearing model is similar to friction node model by steady-state heat load conditions. Described effect can be used as on example of modelling the bearing friction node operations in reciprocating movement during exploitation of engines and machines.
PL
W artykule przedstawiono wyniki komputerowych symulacji przepływu oleju w łożysku z rowkiem na czopie. Rozważono trójwymiarowy, adiabatyczny przepływ, który opisano równaniami Naviera-Stokesa wraz z równaniami energii i ciągłości. Rozważany układ równań rozwiązano metodą elementów skończonych. Na podstawie uzyskanych wyników zidentyfikowano zmiany, jakie w przepływie oleju powoduje modyfikacja geometrii czopa. Wykazano również powiązanie stwierdzonych zmian w przepływie oleju ze zidentyfikowanymi zmianami nośności łożyska.
EN
Computer simulation of the oil flow in a circumferential grooved journal bearing is described in the paper. A circumferentially grooved journal bearing as a limiting state of helical grooved journal bearing was analysed. An adiabatic model of the flow was discussed, and the three-dimensional oil flow was described with the Navier-Stokes, flow continuity and energy equations. The equation system was solved by the finite element method. Based on computer simulations for assumed eccentricity ratios, selected static characteristics of the bearings (effect of groove depth on load capacity, oil flow velocity and oil film maximum pressure) were obtained. Flow phenomena in the oil film were also identified. The local increases of the circumferential component of oil flow velocity and maximum oil film pressure were observed. It is also shown that a groove of suitable dimensions formed on journal do not result in a decrease of the load carrying capacity in relation to conventional bearing.
PL
Podparcie łożysk ślizgowych na czaszy kulistej umożliwia uzyskanie równoległości czopa wału względem powierzchni ślizgowej łożyska. Rozwiązanie tego typu jest często spotykane w maszynach o znacznych gabarytach, w których trudno zapewnić idealne osiowanie wszystkich gniazd łożyskowych. W pracy przedstawiono metodykę badań teoretycznych i doświadczalnych łożysk ślizgowych podpartych na czaszy kulistej. Badania teoretyczne prowadzono z wykorzystaniem programu komputerowego MES oraz programu wyznaczającego charakterystyki filmu olejowego. W celu opisu systemu tribologicznego łożysko–podpora stworzono trójwymiarowy model MES łożyska i gniazda. W czasie badań analizowano wpływ wielu czynników mogących ułatwiać lub utrudniać samonastawność, takich jak luz pomiędzy kulą a gniazdem, wpływ współczynnika tarcia, geometrię gniazda itp. Wyniki badań są aktualnie weryfikowane na specjalnie do tego celu zmodernizowanym stanowisku badawczym.
EN
A new concept of a hydrodynamic bearing computer model with selfaligning spherical support is presented in the paper. It takes into account the interaction between the bearing and spherical support. The model is composed of two modules. The first module is used for calculating hydrodynamic pressure distribution, and the second one (FEM module) describes the tribological characteristics of the spherical support of the bearing. During the simulations, both bearing geometry and spherical support geometry were changed. Several bearings were tested, varying clearance, length and preload. Different spherical seats were also studied, varying clearance and friction coefficient. The influence of the groove in the bearing shell sliding surface on tribological behaviour was also investigated. The proposed computer model offers an efficient design stage simulation of the behaviour of a sliding bearing in a spherical support. The model is being verified during experimental tests in a modernised test rig.
EN
The oil instabilities could occur in journal bearings. New suggested way to prevent the instability is to use controlled external excitation. The relationship between the external excitation and the reaction of the journal is described in the article. This relationship was measured using the model rotor kit RK4. The measured values were compared with the mathematical model. The aim is contribute to setting of the feedback control function.
CS
V kluzných ložiscích může za určitých okolností nastat jev, kterému se říká nestabilita olejového filmu. Nově navrhovanou metodou pro zabránění tohoto jevu je použití řízeného vnějšího buzení pomocí aktuátorů. V článku je popsáno jaký vliv má nesynchronní vnějšího buzení a kdy dojde k potlačení nestability olejového filmu, při otáčkách na počátku vzniku nestability.
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