Advances in Tribology

The concept of two-disc model testing has proven to deliver valuable information for the applicability of new technologies, such as surface structuring, coatings, alternative fluids, or advanced materials, in actual machine elements. In this article an advanced two-disc machine with sophisticated control technology for dry and lubricated setup is presented. (i) All involved components are controlled via a powerful PLC unit leading to the possibility of realising extremely accurate SRRs down to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mn mathvariant="normal">0.1</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math>. (ii) High-speed data acquisition allows local insight into tribological phenomena by providing 72 data points along one shaft rotation. (iii) Several lubrication scenarios such as fluid, mixed, and starved lubrication, as well as dry contacts, can be considered. (iv) Raw-data of all sensors, including normal force, friction force, vibration speed, stiffness (wear), infrared temperature, contact potential, and motor speed, is presented. Some example results of dry polymer-steel tribosystems and lubricated experiments are shown to elucidate the capabilities of the novel test rig.

Jakob Moder

Florian Grün

Michael Stoschka

István Gódor

A Novel Two-Disc Machine for High Precision Friction Assessment

一种新型双盘机用于高精度摩擦评估

The acquisition and evaluation of acoustic emissions (AE) in tribology have proven to be a meaningful tool for condition monitoring and offer possibilities to deepen the understanding of tribological processes. The authors used this technology with the aim of expanding existing test methodologies towards increased visualization capability of tribological processes and investigated the correlation between tribological processes and acoustic emissions on a Ring-on-Disc and a close-to-component journal bearing test setting. The results of this study include the description of friction as well as wear processes and prove the usability of several AE evaluation parameters whereby a close correlation between AE and tribological processes can be shown. Consequently, it was possible to expand the visualization and evaluation capabilities of the test settings offering additional insights by making use of AE.

Philipp Bergmann

Florian Summer

Gabriel Stadler

Expansion of the Metrological Visualization Capability by the Implementation of Acoustic Emission Analysis

通过实施声发射分析扩展计量可视化能力

Polyamide (PA6/6) is often used as a tribological pair in abrasion prevalent applications such as hinges and sliders. PA6/6 is frequently processed by injection moulding and extrusion process. It is known that these processes influence the polymers mechanical behaviour, but their influence on the polymers wear response has not been studied. Hence the present research attempts to study the influence of different manufacturing processes on tribological behaviour for PA6/6. Wear tests were performed on a pin abrading tester (DIN 50322). Abrasion resistance of both extruded and injection moulded PA6/6 were tested at different loads (20 and 35 N). Single-pass (nonoverlapping mode) and multipass testing (overlapping mode) were used to understand the influence of clogging of wear debris. It is evidenced that with increasing load the specific wear rate decreases; moreover, fine abrasives tend to reduce the wear rate. In multipass testing a transfer layer clogged on the counterface that acted as a protective agent and lowers wear rate. Poor mechanical strength of injection moulded polymers is apparently compensated by microstructural response for having a similar wear behaviour between extruded and injection moulded PA 6/6. Hence a proper balance between microstructural and mechanical characteristics is an absolute must in PA 6/6 for better wear performance.

J. Sukumaran

R. Keresztes

G. Kalácska

H. Almaliki

P. D. Neis

P. De Baets

Extruded and Injection Moulded Virgin PA 6/6 as Abrasion Resistant Material

挤压成型和注塑成型的纯PA 6/6作为耐磨材料

The physicochemical and tribological studies of mineral and synthetic commercial engine oils have been carried out to investigate their performance variability and to propose generalized relationship among different physicochemical and performance parameters. Physicochemical parameters have been determined using standard test procedures proposed in ASTM and Indian Standards (BIS). The rheological parameters of these lubricants have been investigated to identify the flow behavior. The tribological performance in terms of their antifriction and antiwear properties has been studied using four-ball tribotester. Correlation and regression analysis has been performed to ascertain relationship among physicochemical and tribological parameters and the causes of performance variability are highlighted. An empirical relation to calculate coefficient of friction as a function of physicochemical properties has been established using regression analysis. The developed relation has fair degree of reliability, as percentage of deviation is less than 20%.

Prashant Thapliyal

G. D. Thakre

Correlation Study of Physicochemical, Rheological, and Tribological Parameters of Engine Oils

发动机油理化、流变和摩擦学参数的相关性研究

The design of the support system (shaft, bearings, and mechanical coupling devices) of the rotor plays a key role in the development of efficient micro-gas turbines (micro-GTs) for distributed power generation. Foil air bearings are the most widespread technical solution well suited to design a reliable support system, although they cannot withstand a large number of start-stop cycles of the units. In order to overcome such limitation, we have recently proposed an innovative support system that takes advantage of spline couplings and two bearing types (e.g., air and rolling-element bearings). The devised support system employs splines as both convenient coupling systems and actuators for the load partition between the two bearing types. In the present work, the helical spline coupling is studied by means of structural FEM analyses including contact simulation in order to design the support system. Numerical results confirm previous findings in that the load transfer through the spline coupling is mainly a function of the helix angle. In addition, friction factor and structural stiffness cannot be neglected in the accurate design of the spline coupling. Such design parameters are now included in the proposed design procedure, which formerly assumed frictionless contact and rigid bodies.

Fabrizio Stefani

Ramon Francesconi

Andrea Perrone

FEM Design of a Cutting-Edge Support System for Micro-GT

微型燃气轮机尖端支撑系统的有限元设计

This paper includes the laboratory and experimental methodology used to compare the effect of using mineral, semi-synthetic, and synthetic engine oil on the parts wear of a four-stroke gasoline internal composition engine (ICE). Three test platforms included three engines with identical, technical, and design specifications. They were operated under the same investment, ambient, and climatic conditions. The first engine was equipped with synthetic oil, the second with semi-synthetic oil, and the third with mineral engine oil. All of them had (SAE10W40 API: SL/CF). All test platforms were operated through three stages with variable loads for up to 1,500 operating hours (hr). Oil drain intervals (ODI) were every 100 operating hours. Used oil samples were taken to analyze the physical and chemical characteristics of viscosity, total base number TBN, flash point, metals wear Irion (Fe), copper (Cu), chromium (Cr), and wear index (WI) to investigate the effect of all oils on the wear of engine parts and by comparing the changes in wear. The used oil analysis (UOA) results were drawn that showed the superiority of the use of synthetic oil over semi-synthetic and mineral. It prolonged the technical engine’s lifetime.

Mohammad Maher Kallas

Mohammad Saed Al Sabek

Younes Saoud

Experimental Comparison of the Effect of Using Synthetic, Semi-Synthetic, and Mineral Engine Oil on Gasoline Engine Parts Wear

合成、半合成和矿物发动机油对汽油发动机部件磨损影响的实验比较

Automobile engines require lubrication to lessen the impact of friction due to the high levels of wear and frictional heat generated by the sliding parts. Wear and friction will cause engine parts to endure for less time, be less reliable, and require more maintenance. Diesel fuel can potentially be replaced with biodiesel among other fuels. Diesel engines have a serious problem with equipment that is lubricated by the fuel itself. This study’s goal is to assess the influence of bio-additives on the diesel fuel tribological behavior and energy balance during the car’s idle running, acceleration, constant speed, and braking. Lubricity issues with reformulated diesel and lubricity test procedures are explained. The relationship between tribology and bio-additives is also briefly illustrated. According to the literature, adding bio-additives to fuel boosts its lubricity. Biodiesel has long been considered an additive with excellent lubricant properties. Even in small amounts, adding biodiesel to diesel fuel can increase its lubricity without the need for conventional lubricity additives. This is especially true for diesel fuel with ultralow sulfur. Diesel fuel characteristics determine the precise blending percentage needed to provide the proper lubricity of maximum 520 μm testing wear scars with a high-frequency reciprocating rig (HFRR), although 2% biodiesel nearly invariably imparts adequate lubricity to biodiesel blends. Tall oil fatty acid (TOFA) was one of the bio-additives investigated by HFRR. When the additive concentration was raised from 0 to 500 g/g, the wear scar diameter (WSD) of nonadditive diesel fuel was lowered by 60.3%, from 630 to 250 μm, and the coefficient of friction (COF) was lowered by 95.7%, from 0.47 to 0.02.

Hailegebrel Zewdie

Getachew Tibba Shunki

Dinku Syoum

Varatharaju Perumal

Pedro Dionisio Remedios Castañeiras

A Review on the Impact of Bio-Additives on Tribological Behavior of Diesel Fuels

柴油燃料中生物添加剂对摩擦学行为影响的综述

Cavitation in hydro turbines causes component deterioration that requires continuous and costly maintenance in the hydroelectric power generation stations. The Tarbela Dam Hydel Project (TDHP) in Pakistan is facing a cavitation problem in the Francis Turbine components, such as the runner and draft tube. Simulation work has been performed to examine and quantify the cavitation rate as a function of the suction head (SH) and flow velocity (FV) by utilizing a homogeneous cavitation model. The result shows that pressure fluctuation is maximum for overcrowded conditions and minimum for rated load conditions. Moreover, a higher cavitation rate is found for the part and overcrowded conditions compared to the rated load condition. Additionally, the cavitation rate becomes 50% higher when the SH increases from 5.54 to 12.34 m. Moreover, SEM results have verified the CFD results that higher FV and SH enhance the cavitation rate. Furthermore, the numerical work is validated by simplified hydrofoil geometry. The computational fluid dynamics results presented a good arrangement with the experimental data.

Adnan Aslam Noon

Aamer Sharif

Melkamu Tadesse Getachew

Riaz Muhammad

Experimental and Numerical Investigation of Cavitation Assessment for Runner Blades in a Francis Turbine

实验与数值研究法向涡轮转轮叶片空化评估

The increased demand for wear-resistant and low-weight components in the automobile industry has led to the utilization of aluminum metal matrix composite parts due to their improved performance. The current work focused on optimizing the tribological factors such as applied load, rotational speed, and percentage weight fraction of the reinforcing particles for minimum dry sliding wear rate of Al6061/nano-Al2O3/quartz hybrid composite fabricated by stir casting. The optimization is performed by using the Taguchi L27 orthogonal array experimental plan, and the result is analyzed by the help of analysis of variance (ANOVA). The result of the optimization reveals that the optimum levels of factors for the minimum wear rate are 10 N, 200 rpm, and 12.5%. Furthermore, the ANOVA result depicts that the applied load has the highest impact (87.83%) on the wear rate, followed by rotational speed (10.06%) and percentage weight fraction of the reinforcement (1.60%). The developed linear regression model reveals that the applied load and the rotational speed have a positive relation with the sliding wear rate. However, the percentage weight fraction of the reinforcement has a negative relation. The confirmation test proves that the predicted value of wear rate using the regression equation at optimum levels has a closer agreement with the experimental result having a 6.934% error. Furthermore, the physical property test reveals that the rise in the weight percentage of quartz particles results in a corresponding increase in the percentage porosity of the hybrid composite.

Dagim Tirfe

Abraham Debebe Woldeyohannes

Bonsa Regassa Hunde

Temesgen Batu

Eaba Geleta

Optimizing the Dry Sliding Wear Behavior of Stir-Casted Al6061/Nano-Al2O3/Quartz Hybrid Metal Matrix Composite Using Taguchi Method

使用田口方法优化搅拌铸造Al6061/纳米Al2O3/石英复合材料干滑动磨损行为

The subject of modeling and predicting roughness parameters in hard machining has been discussed in many literature sources. However, most of these sources cover only the amplitude parameters such as Ra and Rz, leaving it unexplored to the right extent compared to its importance the roughness parameter bearing ratio curve (the Abbott–Firestone curve) which is essential in understanding the actual contact area of mating surfaces. To bridge this gap, this research has developed a mathematical model using the design of experiments method through investigation of the effect of process parameters in hard turning of Steel C55 (DIN) with mixed ceramics MC2 (Al2O3 + TiC). The model predicts the bearing ratio curve parameter Rmr (50% Rz), statistically processed using CADEX and Matlab. The research includes the ANOVA as a complementary tool in validating the generated mathematical model. The research analyzes the effects of material properties, cutting forces, and tool geometry as factors that affect the machining process. Additionally, it emphasizes the robustness of hard turning in consistently producing waviness patterns. Overall, this research provides valuable insights into the predictable effects of parameters on machined surfaces, which contributes to a better understanding of surface finish in metalworking.

Mevludin Shabani

Mite Tomov

Mathematical Modeling of the Bearing Ratio Curve Rmr (50% Rz), through Investigation of the Effect of Process Parameters in Hard Turning of Steel C55 (DIN) with Mixed Ceramics MC2 (Al2O3 + TiC)

通过研究混合陶瓷MC2（Al2O3 + TiC）在C55（DIN）钢硬车削过程中工艺参数对Rmr（50% Rz）支承比曲线的影响，进行数学建模

短名	Adv. Tribol.
Journal Impact	1.50
国际分区	ENGINEERING, MECHANICAL(Q3)

ISSN	1687-5915, 1687-5923
h-index	24

涉及主题	材料科学工程类复合材料物理机械工程量子力学冶金热力学化学有机化学计算机科学数学机械生物地理地质学结构工程摩擦学几何学光学纳米技术
出版信息	出版商: Hindawi Limited，出版周期: ，期刊类型: journal，开源期刊: 是
基本数据	创刊年份: 2023，原创研究文献占比: 0.00%，自引率:0.00%， Gold OA占比: 100.00%
期刊费用	$950详情
平均审稿周期	网友分享经验：13 Weeks

Advances in Tribology

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