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1 – 10 of 300Gabi N. Nehme and Najat G. Nehme
The purpose of variable loading conditions (392 N-785N-392N-785N) with break-in period were used to study interactions between zinc dialkyl dithiophosphate (ZDDP) 0.1 P…
Abstract
Purpose
The purpose of variable loading conditions (392 N-785N-392N-785N) with break-in period were used to study interactions between zinc dialkyl dithiophosphate (ZDDP) 0.1 P% (phosphorus) and fine-grade molybdenum disulfide (MoS2) 3%, in different mixtures of NLGI 2 lithium stearate grease. Four-ball wear tests were used to evaluate the tribological properties of different grease mixtures such as coefficient of friction and wear. ASTM 2266 as reported by earlier studies is useful, but it is not representative of real-life applications where variable loads and speeds and different break-in periods play a role and could change the results and the nature of tribofilms.
Design/methodology/approach
In this study, chemical and mechanical properties of tribofilms were examined. Moreover, design of experiment was used to examine the data and shorten experimentation time. Research described here is investigating variable loading conditions for real-life applications by using a break-in period of 2 min at the start to minimize asperities and establish a clean surface. Design expert (DOE) analyzes responses to reveal those variables that are single factor and those that are multifactor whether synergistically or antagonistically.
Findings
The results indicated that spectrum loading with break-in period showed reduction in wear when tested in greases with ZDDP/MoS2 combinations. Ramping up or down the load every 7.5 min for a rotational speed of 1,200 rpm and a total of 36,000 revolutions or 30-min time slowed the wear properties of lithium-based grease under different MoS2 and ZDDP concentrations. Experiments indicated that wear was largely dependent on the loading condition and ZDDP additives during specific break-in period at 1,200 rotational speed. It is believed that MoS2 greases perform better under spectrum loading and under constant loading when mixed with ZDDP phosphorus.
Originality/value
This research indicates that there is a synergistic interaction between ZDDP, MoS2 and variable loading especially when a break-in period is applied. The results indicated that wear was largely dependent on the specific speed used with spectrum loading as presented in the energy dispersive spectroscopy and the Auger electron spectroscopy analysis, and thus a 3% MoS2 grease with ZDDP (phosphorus: 0.1 Wt.%) are needed to improve the wear resistance and improve the friction characteristics.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2024-0016/
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Mandeep Singh, Deepak Bhandari and Khushdeep Goyal
The purpose of this paper is to examine the mechanical characteristics and optimization of wear parameters of hybrid (TiO2 + Y2O3) nanoparticles with Al matrix using squeeze…
Abstract
Purpose
The purpose of this paper is to examine the mechanical characteristics and optimization of wear parameters of hybrid (TiO2 + Y2O3) nanoparticles with Al matrix using squeeze casting technique.
Design/methodology/approach
The hybrid aluminium matrix nanocomposites (HAMNCs) were fabricated with varying concentrations of titanium oxide (TiO2) and yttrium oxide (Y2O3), from 2.5 to 10 Wt.% in 2.5 Wt.% increments. Dry sliding wear test variables were optimized using the Taguchi method.
Findings
The introduction of hybrid nanoparticles in the aluminium (Al) matrix was evenly distributed in contrast to the base matrix. HAMNC6 (5 Wt.% TiO2 + 5 Wt.% Y2O3) reported the maximum enhancement in mechanical properties (tensile strength, flexural strength, impact strength and density) and decrease in porosity% and elongation% among other HAMNCs. The results showed that the optimal combination of parameters to achieve the lowest wear rate was A3B3C1, or 15 N load, 1.5 m/s sliding velocity and 200 m sliding distance. The sliding distance showed the greatest effect on the dry sliding wear rate of HAMNC6 followed by applied load and sliding velocity. The fractured surfaces of the tensile sample showed traces of cracking as well as substantial craters with fine dimples and the wear worn surfaces were caused by abrasion, cracks and delamination of HAMNC6.
Originality/value
Squeeze-cast Al-reinforced hybrid (TiO2+Y2O3) nanoparticles have been investigated for their impact on mechanical properties and optimization of wear parameters.
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Hongkun Wang, Yongxiang Zhao, Yayun Qi and Yufeng Cao
The serious wear problem of heavy-haul freight vehicle wheels affects the safety and economy of vehicle operation. This paper aims to study wheel wear evolution law and the…
Abstract
Purpose
The serious wear problem of heavy-haul freight vehicle wheels affects the safety and economy of vehicle operation. This paper aims to study wheel wear evolution law and the influence of line parameters on wheel wear of heavy-haul freight, and provide the basis for operation and line maintenance.
Design/methodology/approach
The wheel wear test data of heavy-haul freight vehicles were analyzed. Then a heavy-haul freight vehicle dynamic model was established. The line parameters influencing wheel wear in heavy-haul freight vehicles were also analyzed by the Jendel wear model, and the effects of rail cant, rail gauge, rail profile and line ramp on wheel wear were analyzed.
Findings
A rail cant of 1:40 results in less wheel wear; an increase in the rail gauge can reduce wheel wear; and when matched with the CHN60 rail, the wear depth is relatively small. A decrease of 9.21% in wheel wear depth when matched with the CHN60 rail profile. The ramp of the heavy-haul line is necessary to consider for calculating wheel wear. When the ramp is considered, the wear depth increases by 8.47%. The larger the ramp, the greater the braking force and therefore, the greater of the wheel wear.
Originality/value
This paper first summarizes the wear characteristics of wheels in heavy-haul freight vehicles and then systematically analyzes the effect of line parameters on wheel wear. In particular, this study researched the effects of rail cant, rail gauge, rail profile and line ramp on wheel wear.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2024-0038/
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Cong Ding, Zhizhao Qiao and Zhongyu Piao
The purpose of this study is to design and process the optimal V-shaped microstructure for 7075 aluminum alloy and reveal its wear resistance mechanism and performance.
Abstract
Purpose
The purpose of this study is to design and process the optimal V-shaped microstructure for 7075 aluminum alloy and reveal its wear resistance mechanism and performance.
Design/methodology/approach
The hydrodynamic pressure lubrication models of the nontextured, V-shaped, circular and square microtextures are established. The corresponding oil film pressure distributions are explored. The friction and wear experiments are conducted on a rotating device. The effects of the microstructure shapes and sizes on the wear mechanisms are investigated via the friction coefficients and surface morphologies.
Findings
In comparison, the V-shaped microtexture has the largest oil film carrying capacity and the lowest friction coefficient. The wear mechanism of the V-shaped microtexture is dominated by abrasive and adhesive wear. The V-shaped microtexture has excellent wear resistance under a side length of 300 µm, an interval of 300 µm and a depth of 20 µm.
Originality/value
This study is conductive to the design of wear-resistant surfaces for friction components.
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Ziyan Lu, Feng Qiu, Hui Song and Xianguo Hu
This paper aims to solve the problems molybdenum disulfide (MoS2) nanosheets suffer from inadequate dispersion stability and form a weak lubricating film on the friction surface…
Abstract
Purpose
This paper aims to solve the problems molybdenum disulfide (MoS2) nanosheets suffer from inadequate dispersion stability and form a weak lubricating film on the friction surface, which severely limits their application as lubricant additives.
Design/methodology/approach
MoS2/C60 nanocomposites were prepared by synthesizing molybdenum disulfide (MoS2) nanosheets on the surface of hydrochloric acid-activated fullerenes (C60) by in situ hydrothermal method. The composition, structure and morphology of MoS2/C60 nanocomposites were characterized. Through the high-frequency reciprocating tribology test, its potential as a lubricant additive was evaluated.
Findings
MoS2/C60 nanocomposites that were prepared showed good dispersion in dioctyl sebacate (DOS). When 0.5 Wt.% MoS2/C60 was added, the friction reduction performance and wear resistance improved by 54.5% and 62.7%, respectively.
Originality/value
MoS2/C60 composite nanoparticles were prepared by in-situ formation of MoS2 nanosheets on the surface of C60 activated by HCl through hydrothermal method and were used as potential lubricating oil additives.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2023-0321/
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Ravikantha Prabhu, Sharun Mendonca, Pavana Kumara Bellairu, Rudolf D'Souza and Thirumaleshwara Bhat
This study explores how titanium oxide (TiO2) filler influences the specific wear rate (SWR) in flax fiber-reinforced epoxy composites (FFRCs) through a Taguchi approach. It aims…
Abstract
Purpose
This study explores how titanium oxide (TiO2) filler influences the specific wear rate (SWR) in flax fiber-reinforced epoxy composites (FFRCs) through a Taguchi approach. It aims to boost abrasive wear resistance by incorporating TiO2 filler, promoting sustainable and eco-friendly materials.
Design/methodology/approach
This study fabricates epoxy/flax composites with TiO2 particles (0–8 wt%) using hand layup. Composites were tested for wear following American Society for Testing and Materials (ASTM) G99-05. Statistical analysis used Taguchi design of experiments (DOE), with ANOVA identifying key factors affecting SWR in abrasive sliding conditions.
Findings
The study illuminates how integrating TiO2 filler particles into epoxy/flax composites enhances abrasive wear properties. Statistical analysis of SWR highlights abrasive grit size (grit) as the most influential factor, followed by normal load, wt% of TiO2 and sliding distance. Grit size has the highest effect at 43.78%, and wt% TiO2 filler contributes 15.61% to SWR according to ANOVA. Notably, the Taguchi predictive model closely aligns with experimental results, validating its reliability.
Originality/value
This paper integrates TiO2 filler and flax fibers to form a novel hybrid composite with enhanced tribological properties in epoxy composites. The use of Taguchi DOE and ANOVA offers valuable insights for optimizing control variables, particularly in natural fiber-reinforced composites (NFRCs).
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Yuchun Huang, Haishu Ma, Yubo Meng and Yazhou Mao
This paper aims to study the synergistic lubrication effects of Sn–Ag–Cu and MXene–Ti3C2 to improve the tribological properties of M50 bearing steel with microporous channels.
Abstract
Purpose
This paper aims to study the synergistic lubrication effects of Sn–Ag–Cu and MXene–Ti3C2 to improve the tribological properties of M50 bearing steel with microporous channels.
Design/methodology/approach
M50 matrix self-lubricating composites (MMSC) were designed and prepared by filling Sn–Ag–Cu and MXene–Ti3C2 in the microporous channels of M50 bearing steel. The tribology performance testing of as-prepared samples was executed with a multifunction tribometer. The optimum hole size and lubricant content, as well as self-lubricating mechanism of MMSC, were studied.
Findings
The tribological properties of MMSC are strongly dependent on the synergistic lubrication effect of MXene–Ti3C2 and Sn–Ag–Cu. When the hole size of microchannel is 1 mm and the content of MXene–Ti3C2 in mixed lubricant is 4 wt.%, MMSC shows the lowest friction coefficient and wear rate. The Sn–Ag–Cu and MXene–Ti3C2 are extruded from the microporous channels and spread to the friction interface, and a relatively complete lubricating film is formed at the friction interface. Meanwhile, the synergistic lubrication of Sn–Ag–Cu and MXene–Ti3C2 can improve the stability of the lubricating film, thus the excellent tribological property of MMSC is obtained.
Originality/value
The results help in deep understanding of the synergistic lubrication effects of Sn–Ag–Cu and MXene–Ti3C2 on the tribological properties of M50 bearing steel. This work also provides a useful reference for the tribological design of mechanical components by combining surface texture with solid lubrication.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0381/
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Xingwen Wu, Zhenxian Zhang, Wubin Cai, Ningrui Yang, Xuesong Jin, Ping Wang, Zefeng Wen, Maoru Chi, Shuling Liang and Yunhua Huang
This review aims to give a critical view of the wheel/rail high frequency vibration-induced vibration fatigue in railway bogie.
Abstract
Purpose
This review aims to give a critical view of the wheel/rail high frequency vibration-induced vibration fatigue in railway bogie.
Design/methodology/approach
Vibration fatigue of railway bogie arising from the wheel/rail high frequency vibration has become the main concern of railway operators. Previous reviews usually focused on the formation mechanism of wheel/rail high frequency vibration. This paper thus gives a critical review of the vibration fatigue of railway bogie owing to the short-pitch irregularities-induced high frequency vibration, including a brief introduction of short-pitch irregularities, associated high frequency vibration in railway bogie, typical vibration fatigue failure cases of railway bogie and methodologies used for the assessment of vibration fatigue and research gaps.
Findings
The results showed that the resulting excitation frequencies of short-pitch irregularity vary substantially due to different track types and formation mechanisms. The axle box-mounted components are much more vulnerable to vibration fatigue compared with other components. The wheel polygonal wear and rail corrugation-induced high frequency vibration is the main driving force of fatigue failure, and the fatigue crack usually initiates from the defect of the weld seam. Vibration spectrum for attachments of railway bogie defined in the standard underestimates the vibration level arising from the short-pitch irregularities. The current investigations on vibration fatigue mainly focus on the methods to improve the accuracy of fatigue damage assessment, and a systematical design method for vibration fatigue remains a huge gap to improve the survival probability when the rail vehicle is subjected to vibration fatigue.
Originality/value
The research can facilitate the development of a new methodology to improve the fatigue life of railway vehicles when subjected to wheel/rail high frequency vibration.
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Gaopeng Zhang, Linfan Wang and Hu Meng
Based on the knowledge-attitude-behavior model, this study is aimed at investigating the influential mechanism underlying the purchase of green clothing by dividing this clothing…
Abstract
Purpose
Based on the knowledge-attitude-behavior model, this study is aimed at investigating the influential mechanism underlying the purchase of green clothing by dividing this clothing category into green home-in wear and home-out wear within the context of green consumption. The mediating effects of perceived greenwashing (PG), perceived value (PV) and expected moral benefit (EMB) and the moderating effect of green clothing type (GCT) were examined.
Design/methodology/approach
The data for this study were collected from 366 valid samples through a between-subject design survey administered in China. Moderation analysis and mediation analysis using SPSS/PROCESS macro were applied to test the proposed hypotheses.
Findings
The results indicate that consumers' level of environmental knowledge (EKL) not only has a direct effect on purchase intention (PI) but also has an indirect effect through perceived value and expected moral benefit. However, perceived greenwashing did not play a mediating role in this relationship.
Originality/value
The study's findings show a moderating effect of green clothing type (green home-in wear vs green home-out wear). That is, compared to green home-out wear, the relationship between expected moral benefit and perceived greenwashing for green home-in wear had a weaker negative effect on purchase intentions.
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Mauricio Pérez Giraldo, Mauricio Vasquez, Alejandro Toro, Robison Buitrago-Sierra and Juan Felipe Santa
This paper aims to develop a stable gel-type lubricant emulating commercial conditions. This encompassed rheological and tribological assessments, alongside field trials on the…
Abstract
Purpose
This paper aims to develop a stable gel-type lubricant emulating commercial conditions. This encompassed rheological and tribological assessments, alongside field trials on the Medellín tram system.
Design/methodology/approach
The gel-type lubricant with graphite and aluminum powder is synthesized. Rheological tests, viscosity measurements and linear viscoelastic regime assessments are conducted. Subsequently, tribological analyses encompassing four-ball and twin disc methods are executed. Finally, real-world testing is performed on the Medellín tram system.
Findings
An achieved lubricant met the stipulated criteria, yielding innovative insights into the interaction of graphite and aluminum powder additives under varying tests.
Originality/value
Novel findings are unveiled regarding the interaction of graphite and aluminum powder additives in tribological, rheological and real-world trials. In addition, the wear behavior of polymers is observed, along with the potential utilization of such additives in tramway systems.
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