Modeling of Piston Ring Assembly and Connecting Rod Bearing Lubrication and Tribological Performance

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An Overview of Engine Components Friction Modeling

Development of efficient internal combustion engines (ICEs) is receiving wide attention due to increasing environmental legislation limits and fuel and emission costs. In order to improve ICEs performance, it is vital to gain insight of lubrication mechanism and tribological performance of engine reciprocating and rotating components. Analytical modeling of engine components such as piston ring assembly (PRA), connecting rod big eye and main journal bearings tribological behavior widely accepted as reliable tool by researchers and car industries. The principle aim of this paper is to briefly describe technical aspects and governing equations as well as numerical approaches apply to simulat

Effect of Barium (Ba) Addition on Dry Turning of a Commercial Al-20Mg2Si-2Cu Metal Matrix Composite

The principle aim of this study was to observe the effect of machining parameters as well as the separate additions of 0.2wt% barium (Ba) on the machinability of Al-20%Mg2Si in situ metal matrix composite. Microstructure alteration, surface roughness and cutting temperature were taken into account as indices to examine the effect of modifier and machinability during dry turning. The results showed that addition of Ba as modifier reagent results in lower cutting temperature and better surface roughness due to the formation of Ba compound and modification of morphology of Mg2Si reinforcement particle

The Effects of Oil Film Shape on Piston Ring and Liner Tribology Under Mixed Lubrication

Mechanical power loss reduction at lubricated reciprocating and rotating components is recognized as an approach to improve the efficiency and to reduce the emissions of Internal Combustion Engines (ICEs). To achieve these goals, the instantaneous investigation of lubrication characteristics is required. Piston ring pack is of paramount importance as it is known as major contributor to frictional losses and energy dissipation. Applying Reynolds equation and lubrication theory to study piston ring tribology, requires specifying of boundary conditions. Oil film characteristics (shape and thickness) and generated hydrodynamic pressure are under influence of considered boundary conditions. Besides, the type of selected boundary conditions affects analysis robustness and sensitivity. During engine strokes, piston ring enjoys hydrodynamic and mixed lubrication regimes. The principle aim of the current study is to examine the effects of alternative boundary conditions: Half Sommerfeld, oil separation and Reynolds cavitation and reformation conditions on piston ring tribology under isothermal mixed and hydrodynamic lubrication regimes. This article demonstrates that different boundary conditions are suited to different operating conditions with respect to load, speed and temperature as well as crank angle, i.e., relative position of ring with respect to the liner. Thicker oil film thickness has been calculated applying half Sommerfeld boundary conditions under either hydrodynamic or mixed lubrication regimes followed by oil separation due to larger effective of the ring width. It was observed that considering oil separation boundary conditions results in lower deviation from experimental data, followed by Sommerfeld boundary conditions under mixed lubrication

Numerical Study of Power Loss and Lubrication of Connecting Rod Big-End

A hydrodynamic lubrication analysis for connecting rod big-end bearing is conducted. The effects of engine speed, operating condition, lubricant viscosity and oil temperature on tribological performance of big-end bearing have been examined. Force equilibrium is solved to define instantaneous eccentricity between journal and bearing to have accurate estimation of oil film thickness at interface of connecting rod big-end bearing and crankpin. Connecting rod big-end is treated as π film hydrodynamic journal bearing and finite difference scheme is applied to calculate generated hydrodynamic pressure and frictional power loss at each crank angle. Beside the development of analytical formulation, well-known Mobility model introduced by Booker has been employed to be compared with the analytical model. The presented analytical model reduces the complexity and the numerical effort with respect to Mobility method, thus shortening the computation time. The simulation results show good agreement between analytical model, Mobility approach and experimental data

Correlation between Microstructural Alteration, Mechanical Properties and Manufacturability after Cryogenic Treatment: A Review

Cryogenic treatment is a supplemental structural and mechanical properties refinement process to conventional heat treatment processes, quenching, and tempering. Cryogenic treatment encourages the improvement of material properties and durability by means of microstructural alteration comprising phase transfer, particle size, and distribution. These effects are almost permanent and irreversible; furthermore, cryogenic treatment is recognized as an eco-friendly, nontoxic, and nonexplosive process. In addition, to encourage the application of sustainable techniques in mechanical and manufacturing engineering and to improve productivity in current competitive markets, cryo-treatment can be considered as a promising process. However, while improvements in the properties of materials after cryogenic treatment are discussed by the majority of reported studies, the correlation between microstructural alteration and mechanical properties are unclear, and sometimes the conducted investigations are contradictory with each other. These contradictions provide different approaches to perform and combine cryogenic treatment with pre-and post-processing. The present literature survey, mainly focused on the last decade, is aimed to address the effects of cryogenic treatment on microstructural alteration and to correlate these changes with mechanical property variations as a consequence of cryo-processing. The conclusion of the current review discusses the development and outlines the trends for the future research in this field

An Overview of Additive Manufacturing Technologies—A Review to Technical Synthesis in Numerical Study of Selective Laser Melting

Additive Manufacturing (AM) processes enable their deployment in broad applications from aerospace to art, design, and architecture. Part quality and performance are the main concerns during AM processes execution that the achievement of adequate characteristics can be guaranteed, considering a wide range of influencing factors, such as process parameters, material, environment, measurement, and operators training. Investigating the effects of not only the influential AM processes variables but also their interactions and coupled impacts are essential to process optimization which requires huge efforts to be made. Therefore, numerical simulation can be an effective tool that facilities the evaluation of the AM processes principles. Selective Laser Melting (SLM) is a widespread Powder Bed Fusion (PBF) AM process that due to its superior advantages, such as capability to print complex and highly customized components, which leads to an increasing attention paid by industries and academia. Temperature distribution and melt pool dynamics have paramount importance to be well simulated and correlated by part quality in terms of surface finish, induced residual stress and microstructure evolution during SLM. Summarizing numerical simulations of SLM in this survey is pointed out as one important research perspective as well as exploring the contribution of adopted approaches and practices. This review survey has been organized to give an overview of AM processes such as extrusion, photopolymerization, material jetting, laminated object manufacturing, and powder bed fusion. And in particular is targeted to discuss the conducted numerical simulation of SLM to illustrate a uniform picture of existing nonproprietary approaches to predict the heat transfer, melt pool behavior, microstructure and residual stresses analysis

Industry 4.0 Impact on Evolution of Product Development: The Bicycle Saddle Case Study

The emerging new technologies, the rapid change of market demand, and the influence of society moved the companies to be innovative and to improve their product as continuously as effectively. Therefore, the need for smart manufacturing systems and smart products arises to allow the manufacturer satisfying current customer needs, within a context of highly competitive market. The Industry 4.0 initiative provides a base toward the smart manufacturing, aimed at producing the smart and highly connected product. This study analyzes the role of Industry 4.0 technologies in the product development process. Particularly, it investigates how the whole life cycle of product is conceived, to comply with the Industry 4.0 main features. The paper focuses upon a customized bike saddle, assumed as a case study. The saddle comfort depends on many factors, including the rider anatomy. Therefore, it raises the necessity of profound customization to satisfy the user needs. Artificial intelligence techniques, such as data mining for market research, deep learning for customized design, and additive manufacturing technologies, as the stereolithography for 3D printing, concur all to enable the implementation of the Industry 4.0 paradigm, and to innovate significantly the product

Structural performance of isolated steel beam-to-column connection

The present study attempts to determine the main characteristics of a new proposed steel connection retrofitted by an elastomeric isolator. Its stiffness, strength, and ductility are investigated. The elastomeric isolators were designed according to the Japanese Society of Base Isolation with the aim of improving the energy dissipation of the connection. Experimental tests were conducted to evaluate the moment rotation (M-θ) curve of the proposed connection as well as of fully-rigid (SidePlate) and semi-rigid (flush end-plate) connections. The behaviour of beams with flexible and fixed-end connections was also studied by classical methods of analysis. The initial stiffness and classification index of the connections were identified by an analytical calculation in compliance with the methods suggested by Eurocode 3 Part 1-8 and ANSI/AISC 360-10. The results confirmed that the new proposed connection can be classified as a flexible connection in terms of its initial stiffness; however, it developed 90% of the plastic moment capacity of a connected beam. Besides, it showed that the isolated connection did address the AISC drift angle capacity requirement of θSD for a special moment frame (SMF)