W. Sawczuk, A. Merkisz-Guranowska, Armando-Miguel Rilo Cañás, S. Kołodziejski
The paper presents the results of investigations of a railway disc brake system related to the mass wear of its brake pads. The tests were carried out on a certified brake stand designed to determine the friction-mechanical characteristics of the brakes. The test stand was additionally equipped with a thermographic camera to observe the contact points of the brake pads with the disc. Particular attention was drawn to investigating the impact on the mass wear of the brake pads of such parameters of the braking process as contact surface of the brake pad with the rotor, thickness of the brake pads as the indicator of their initial wear, clamping force of the pads against the rotor, rail vehicle mass to be decelerated, and speed, at which the deceleration begins. The scientific aim of the paper is to present the relations between the mass wear of the brake pads and the quantities that characterize the braking process. A regression model was determined to estimate the wear of the brake pads based on a single braking process with the preset input quantities.
{"title":"New approach to brake pad wear modelling based on test stand friction-mechanical investigations","authors":"W. Sawczuk, A. Merkisz-Guranowska, Armando-Miguel Rilo Cañás, S. Kołodziejski","doi":"10.17531/ein.2022.3.3","DOIUrl":"https://doi.org/10.17531/ein.2022.3.3","url":null,"abstract":"The paper presents the results of investigations of a railway disc brake system related to the mass wear of its brake pads. The tests were carried out on a certified brake stand designed to determine the friction-mechanical characteristics of the brakes. The test stand was additionally equipped with a thermographic camera to observe the contact points of the brake pads with the disc. Particular attention was drawn to investigating the impact on the mass wear of the brake pads of such parameters of the braking process as contact surface of the brake pad with the rotor, thickness of the brake pads as the indicator of their initial wear, clamping force of the pads against the rotor, rail vehicle mass to be decelerated, and speed, at which the deceleration begins. The scientific aim of the paper is to present the relations between the mass wear of the brake pads and the quantities that characterize the braking process. A regression model was determined to estimate the wear of the brake pads based on a single braking process with the preset input quantities.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"16 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77884115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flexible operation of coal-fired power plants contributes to the intensification of the life consumption processes, which is a serious problem especially in the case of units with a long in-service time. In steam turbine rotors, the crack propagation rate and material wear caused by low-cycle fatigue increase. The aim of the research is an attempt to forecast the development of these processes and to estimate the probability of critical elements damage, such as the high-pressure and intermediate-pressure rotors. In the stress state analyses, the finite element method (FEM) is used, the Monte Carlo method and the second order reliability method (SORM) is apply to calculate the probability of failure. It is proposed to use risk analysis to plan preventive maintenance of the turbine. The optimal intervals for carrying out diagnostic tests and prophylactic repairs is determined for various operating scenarios and various failure scenarios. This enables a reduction of the costs while ensuring the safety of the turbine's operation.
{"title":"Steam turbine maintenance planning based on forecasting of life consumption processes and risk analysis","authors":"A. Rusin, Martyna Tomala","doi":"10.17531/ein.2022.3.1","DOIUrl":"https://doi.org/10.17531/ein.2022.3.1","url":null,"abstract":"Flexible operation of coal-fired power plants contributes to the intensification of the life\u0000consumption processes, which is a serious problem especially in the case of units with a long in-service time. In steam turbine rotors, the crack propagation rate and material wear caused by low-cycle fatigue increase. The aim of the research is an attempt to forecast the development of these processes and to estimate the probability of critical elements damage, such as the high-pressure and intermediate-pressure rotors. In the stress state analyses, the finite element method (FEM) is used, the Monte Carlo method and the second order reliability method (SORM) is apply to calculate the probability of failure. It is proposed to use risk analysis to plan preventive maintenance of the turbine. The optimal intervals for carrying out diagnostic tests and prophylactic repairs is determined for various operating scenarios and various failure scenarios. This enables a reduction of the costs while ensuring the safety of the turbine's operation.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"96 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79061990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Izdebski, I. Jacyna-Gołda, Marcin Nivette, E. Szczepański
The article presents a method of selecting a fleet of vehicles with a homogeneous structure for tasks based on the statistical characteristics of their operational parameters. The selection of a vehicle fleet for tasks is one of the stages of vehicle fleet management in transport companies. The selection of a vehicle fleet for tasks has been defined as the allocation of a vehicle model to a given company, which is associated with the unification of the vehicle fleet to one specific type. The problem of selecting a fleet of vehicles has been presented in a multi-criteria approach. The operational parameters assessing the selection of vehicles for the tasks are mileage and the number of days to the first and subsequent failure, and vehicle maintenance costs. The developed method of selecting a fleet of vehicles for the tasks consists of two stages. In the first stage, the average operating parameter values are determined using statistical inference. In the second stage, using the MAJA method, a unified model of the fleet of vehicles operating in the enterprise is established.
{"title":"Selection of a fleet of vehicles for tasks based on the statistical characteristics of their operational parameters","authors":"M. Izdebski, I. Jacyna-Gołda, Marcin Nivette, E. Szczepański","doi":"10.17531/ein.2022.3.2","DOIUrl":"https://doi.org/10.17531/ein.2022.3.2","url":null,"abstract":"The article presents a method of selecting a fleet of vehicles with a homogeneous structure for tasks based on the statistical characteristics of their operational parameters. The selection of a vehicle fleet for tasks is one of the stages of vehicle fleet management in transport companies. The selection of a vehicle fleet for tasks has been defined as the allocation of a vehicle model to a given company, which is associated with the unification of the vehicle fleet to one specific type. The problem of selecting a fleet of vehicles has been presented in a multi-criteria approach. The operational parameters assessing the selection of vehicles for the tasks are mileage and the number of days to the first and subsequent failure, and vehicle maintenance costs. The developed method of selecting a fleet of vehicles for the tasks consists of two stages. In the first stage, the average operating parameter values are determined using statistical inference. In the second stage, using the MAJA method, a unified model of the fleet of vehicles operating in the enterprise is established.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"43 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82537201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Łyskawiński, C. Jędryczka, D. Stachowiak, Piotr Łukaszewicz, M. Czarnecki
The aim of this study was to investigate and analyse the synchronous reluctance machine. An accurate method for determining the lumped parameters of an equivalent circuit of the studied machine has been proposed. The method is based on the phase currents and voltages analysis at low slip operation. Experimental research of a synchronous reluctance machine is supplemented by simulation studies. The field-circuit model of electromagnetic phenomena in the considered motor was developed and used in simulation. The proposed method allows the numerical model to be verified by comparing the calculated and measured torqueangle characteristics of the machine. The test results obtained are presented and discussed. Achieved satisfactory concordance between simulation and experiment results proves that the proposed approach can be useful in the synthesis of reliable synchronous reluctance machines as well as in their control systems.
{"title":"Finite element analysis and experimental verification of high reliability synchronous reluctance machine","authors":"W. Łyskawiński, C. Jędryczka, D. Stachowiak, Piotr Łukaszewicz, M. Czarnecki","doi":"10.17531/ein.2022.2.20","DOIUrl":"https://doi.org/10.17531/ein.2022.2.20","url":null,"abstract":"The aim of this study was to investigate and analyse the synchronous reluctance machine.\u0000An accurate method for determining the lumped parameters of an equivalent circuit of the\u0000studied machine has been proposed. The method is based on the phase currents and voltages analysis at low slip operation. Experimental research of a synchronous reluctance machine is supplemented by simulation studies. The field-circuit model of electromagnetic phenomena in the considered motor was developed and used in simulation. The proposed method allows the numerical model to be verified by comparing the calculated and measured torqueangle characteristics of the machine. The test results obtained are presented and discussed. Achieved satisfactory concordance between simulation and experiment results proves that the proposed approach can be useful in the synthesis of reliable synchronous reluctance machines as well as in their control systems.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"18 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72411417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ł. Witanowski, Łukasz Breńkacz, Natalia Szewczuk-Krypa, Marta Dorosińska-Komor, Bartosz Puchalski
In comparison to the traditional solutions, active bearings offer great operating flexibility, ensure better operating conditions over a wider range of rotational speeds and are safe to use. In order to ensure optimum bearing performance a bearing control system is used that adapts different geometries during device operation. The selection of optimal controller parameters requires the use of modern optimization methods that make it possible to quickly achieve the assumed parameters. This article presents the method that has been employed to select the parameters of a proportional integral derivative (PID) controller, in which both stochastic algorithms and hybrid methods have been compared. The results show that all of the used algorithms were able to reach the global optimum but only the hybrid algorithm was repeatable in all runs within a low value of the standard deviation. The best solution will be proposed in the future to control an active foil bearing. Analysing of this paper would help to prevent failures of active foil bearing used in the designed rotating machine.
{"title":"Comparable analysis of PID controller settings in order to ensure reliable operation of active foil bearings","authors":"Ł. Witanowski, Łukasz Breńkacz, Natalia Szewczuk-Krypa, Marta Dorosińska-Komor, Bartosz Puchalski","doi":"10.17531/ein.2022.2.19","DOIUrl":"https://doi.org/10.17531/ein.2022.2.19","url":null,"abstract":"In comparison to the traditional solutions, active bearings offer great operating flexibility, ensure better operating conditions over a wider range of rotational speeds and are safe to use. In order to ensure optimum bearing performance a bearing control system is used that adapts different geometries during device operation. The selection of optimal controller parameters requires the use of modern optimization methods that make it possible to quickly achieve the assumed parameters. This article presents the method that has been employed to select the parameters of a proportional integral derivative (PID) controller, in which both stochastic algorithms and hybrid methods have been compared. The results show that all of the used algorithms were able to reach the global optimum but only the hybrid algorithm was repeatable in all runs within a low value of the standard\u0000deviation. The best solution will be proposed in the future to control an active foil bearing.\u0000Analysing of this paper would help to prevent failures of active foil bearing used in the\u0000designed rotating machine.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"14 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86884621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Global Navigation Satellite System (GNSS) are widely used in many areas of human life and activity. The proper functioning of GNSS systems depends on several factors, the most important of which is the correct knowledge of time. The position indirectly is based on the knowledge of the distance, which is determined based on time with the knowledge of the speed of the electromagnetic wave. Thus, proper (accurate) knowledge of time (GNSS clock stability) is a key to precise positioning. In this text, the long-term stability of the GNSS station clocks covering the years 1994-2020 was analysed. For this purpose, the corrections of the clocks at selected permanent stations were used, and their stability was determined for all years separately. Then the change of clock stability over time and the search for correlation were analysed. As the results showed, there are clearly differences between four of the type of oscillators analysed. In case of the comparison on an annual basis, no change over time was found.
{"title":"Aging of ground Global Navigation Satellite System oscillators","authors":"K. Maciuk","doi":"10.17531/ein.2022.2.18","DOIUrl":"https://doi.org/10.17531/ein.2022.2.18","url":null,"abstract":"Global Navigation Satellite System (GNSS) are widely used in many areas of human life\u0000and activity. The proper functioning of GNSS systems depends on several factors, the most\u0000important of which is the correct knowledge of time. The position indirectly is based on\u0000the knowledge of the distance, which is determined based on time with the knowledge of\u0000the speed of the electromagnetic wave. Thus, proper (accurate) knowledge of time (GNSS\u0000clock stability) is a key to precise positioning. In this text, the long-term stability of the\u0000GNSS station clocks covering the years 1994-2020 was analysed. For this purpose, the\u0000corrections of the clocks at selected permanent stations were used, and their stability was\u0000determined for all years separately. Then the change of clock stability over time and the\u0000search for correlation were analysed. As the results showed, there are clearly differences\u0000between four of the type of oscillators analysed. In case of the comparison on an annual\u0000basis, no change over time was found.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"31 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81091710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Milenović, Srđan M. Bošnjak, Nebojša B. Gnjatović, A. Obradović
Identification of the basic parameters of static stability (BPSS) of the slewing superstructure is the key step in solving the problem of its static stability, as well as static stability of the entire bucket wheel excavator (BWE). Specificity of the slewing superstructure examined in this paper lies in the kinematic breakdown system (KBS) which prevents the loss of static stability on the counterweight side. Development of a unique method for the formation and two-step validation of the calculation models for this particular design concept was the main objective of the presented research. A two-step validation of the analytical models is conducted based on the experimental results. As the outcome, the final calculation model formed in such manner represents an accurate basis both for the proof of static stability and for the monitoring of the BPSS during exploitation. By comparing the results of the control weighing and the referent values of the final calculation model it was concluded that the existing double-walled bucket wheel represents a 'weak point' of the considered BWE.
{"title":"Bucket wheel excavators with a kinematic breakdown system: Identification and monitoring of the basic parameters of static stability of the slewing superstructure","authors":"I. Milenović, Srđan M. Bošnjak, Nebojša B. Gnjatović, A. Obradović","doi":"10.17531/ein.2022.2.17","DOIUrl":"https://doi.org/10.17531/ein.2022.2.17","url":null,"abstract":"Identification of the basic parameters of static stability (BPSS) of the slewing superstructure is the key step in solving the problem of its static stability, as well as static stability of the entire bucket wheel excavator (BWE). Specificity of the slewing superstructure examined in this paper lies in the kinematic breakdown system (KBS) which prevents the loss of static stability on the counterweight side. Development of a unique method for the formation and two-step validation of the calculation models for this particular design concept was the main objective of the presented research. A two-step validation of the analytical models is conducted based on the experimental results. As the outcome, the final calculation model formed in such manner represents an accurate basis both for the proof of static stability and for the monitoring of the BPSS during exploitation. By comparing the results of the control weighing and the referent values of the final calculation model it was concluded that the existing double-walled bucket wheel represents a 'weak point' of the considered BWE.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88618345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Czapp, H. Tariq, Seweryn Szultka, Agata Szultka, E. Zaitseva, V. Levashenko
Residual current devices (RCDs) are most popular devices used in low-voltage installations for protection against electric shock and fire. In cases of high risk of electric shock the application of RCDs is mandatory. Currently, the spread of local direct current (DC) microgrids is widely considered. This creates new challenges for protective systems, in particular those based on RCDs. The main purpose of the research is to test the operation of B-type RCDs by simulating the conditions that may occur in DC microgrids as well as assessment of the effectiveness of electrical safety with the use of such RCDs. The research has revealed that theoretically identical RCDs in terms of technical data can have different tripping properties, including no reaction to residual direct current, which poses a risk of electric shock. This signalizes the necessity of extension of the normative tests performed by manufacturers. The scope of these additional RCDs tests is indicated, from the point of view of the persons’ safety in DC microgrids.
{"title":"Electrical safety in low-voltage DC microgrids with B-type residual current devices","authors":"S. Czapp, H. Tariq, Seweryn Szultka, Agata Szultka, E. Zaitseva, V. Levashenko","doi":"10.17531/ein.2022.2.16","DOIUrl":"https://doi.org/10.17531/ein.2022.2.16","url":null,"abstract":"Residual current devices (RCDs) are most popular devices used in low-voltage installations for protection against electric shock and fire. In cases of high risk of electric shock the application of RCDs is mandatory. Currently, the spread of local direct current (DC) microgrids is widely considered. This creates new challenges for protective systems, in particular those based on RCDs. The main purpose of the research is to test the operation of B-type RCDs by simulating the conditions that may occur in DC microgrids as well as assessment of the effectiveness of electrical safety with the use of such RCDs. The research has revealed that theoretically identical RCDs in terms of technical data can have different tripping properties, including no reaction to residual direct current, which poses a risk of electric shock. This signalizes the necessity of extension of the normative tests performed by manufacturers. The scope of these additional RCDs tests is indicated, from the point of view of the persons’ safety in DC microgrids.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"4 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80914104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nowadays, systems are more complex and require high reliability for their components, especially critical system components. Therefore, to avoid serious damage, system are often replaced before the actual failure. The replaced parts are considered to have “soft failure”, and the limit in which the parts are replaced is known as the critical level of the degradation process. Determining the appropriate value of the critical level for a product is an important problem in their exploitation, as well as for predicting the Mean Time to Failure (MTTF) or Remaining Useful Lifetime (RUL) of this product based on the degradation data by the mathematical models. In this article, an approach in determining the critical levels based on failure data from an accelerated test is introduced. This approach is applied with the degradation process of Light-Emitting Diodes (LED) in an accelerated test and a type of Wiener process-based model is used to predict the MTTF or RUL of LED based on their degradation data and the found critical level.
{"title":"An approach in determining the critical level of degradation based on results of accelerated test","authors":"A. Hoang, Z. Vintr, D. Valis, D. Mazurkiewicz","doi":"10.17531/ein.2022.2.14","DOIUrl":"https://doi.org/10.17531/ein.2022.2.14","url":null,"abstract":"Nowadays, systems are more complex and require high reliability for their components,\u0000especially critical system components. Therefore, to avoid serious damage, system are often replaced before the actual failure. The replaced parts are considered to have “soft failure”, and the limit in which the parts are replaced is known as the critical level of the degradation process. Determining the appropriate value of the critical level for a product is an important problem in their exploitation, as well as for predicting the Mean Time to Failure (MTTF) or Remaining Useful Lifetime (RUL) of this product based on the degradation data by the mathematical models. In this article, an approach in determining the critical levels based on failure data from an accelerated test is introduced. This approach is applied with the degradation process of Light-Emitting Diodes (LED) in an accelerated test and a type of Wiener process-based model is used to predict the MTTF or RUL of LED based on their degradation data and the found critical level.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"37 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80177939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Slawomir Wos, W. Koszela, A. Dzierwa, R. Reizer, P. Pawlus
The purpose of this work is to study the effect of oil pocket shape and density on friction in reciprocating sliding. The experiments were conducted in reciprocating motion under starved lubrication conditions. Tribological tests were performed using an Optimol SRV5 tribotester. The frictional pair consisted of two discs of 42CrMo4 steel. One disc was laser textured. The oil pockets had circular and sandglass shapes. Disc samples of various texture shapes were characterized by the same pit-area ratios. The operating parameters were the same for all friction pairs. In most cases, surface texturing led to reductions in friction force value and scatter. For both dimple shapes, the best tribological properties were achieved for oil pocket density of 9%. When discs with circular dimples were tested, the highest resistance to motion was received for the highest pit-area ratio of 9%. On the contrary, the worst tribological performance of discs with sandglass-shaped oil pockets of sandglass shape were obtained for the largest oil pocket density of 22%.
{"title":"Effects of oil pocket shape and density on friction in reciprocating sliding","authors":"Slawomir Wos, W. Koszela, A. Dzierwa, R. Reizer, P. Pawlus","doi":"10.17531/ein.2022.2.15","DOIUrl":"https://doi.org/10.17531/ein.2022.2.15","url":null,"abstract":"The purpose of this work is to study the effect of oil pocket shape and density on friction in reciprocating sliding. The experiments were conducted in reciprocating motion under starved lubrication conditions. Tribological tests were performed using an Optimol SRV5 tribotester. The frictional pair consisted of two discs of 42CrMo4 steel. One disc was laser textured. The oil pockets had circular and sandglass shapes. Disc samples of various texture shapes were characterized by the same pit-area ratios. The operating parameters were the same for all friction pairs. In most cases, surface texturing led to reductions in friction force value and scatter. For both dimple shapes, the best tribological properties were achieved for oil pocket density of 9%. When discs with circular dimples were tested, the highest resistance to motion was received for the highest pit-area ratio of 9%. On the contrary, the worst tribological performance of discs with sandglass-shaped oil pockets of sandglass shape were obtained for the largest oil pocket density of 22%.","PeriodicalId":50549,"journal":{"name":"Eksploatacja I Niezawodnosc-Maintenance and Reliability","volume":"18 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72887264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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