Tribology Letters最新文献

{"title":"On the Adhesive Interaction Between Metals in Atomistic Simulations of Friction and Wear","authors":"Mohammad Aramfard,&nbsp;Luca Avanzi,&nbsp;Lucia Nicola","doi":"10.1007/s11249-024-01865-1","DOIUrl":"10.1007/s11249-024-01865-1","url":null,"abstract":"<div><p>Atomistic simulations are performed to assess how the main characteristics of a pairwise interatomic potential function can affect the occurrence of wear. A Morse-like potential is tailored in its attractive part such as to vary independently the cut-off radius and the maximum value of the attractive (adhesive) force. An ideal numerical experiment is then performed where the interaction between a metal crystal and a probe changes, while their material properties are not affected, to isolate the behavior of the interface. Force functions with larger adhesive force can loosely be interpreted as describing dry contacts while those with smaller adhesive force can be interpreted as describing lubricated contacts. Results demonstrate that the occurrence of wear is strongly dependent on the shape of the interatomic force field, and more specifically on the combination of maximum adhesive force and effective length of the interatomic attraction. Wear can initiate also at small adhesive energy, provided that the maximum adhesive force between atoms is large. When the surface of the crystal is taken to be rough instead of flat, the effect of the interatomic potential function on friction and wear becomes smaller, as the atoms belonging to the roughness are weakly bound to the rest of the crystal and are easily dislodged with any of the force functions we used.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-024-01865-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting the Metal Ion Release From CoCrMo Alloy–UHMWPE Tribocorrosion Contacts","authors":"Shoufan Cao,&nbsp;Yunkun Wang,&nbsp;Zhanpeng Yang,&nbsp;Yi Liang,&nbsp;Yuanxun Fan","doi":"10.1007/s11249-024-01880-2","DOIUrl":"10.1007/s11249-024-01880-2","url":null,"abstract":"<div><p>Due to tribocorrosion, metal ions are released from metallic components in hip implants and cause adverse reactions. The adverse reaction sensitivity to metal ions showed high dependency on individual patient and it has been recognized that adverse reactions even occur in patients with metal-on-polymer articulations. In this study, based on a tribocorrosion model for CoCrMo alloy, a lubricated wear accelerated corrosion model was developed for CoCrMo alloy–UHMWPE tribocorrosion contacts. The model was verified and calibrated using laboratory tribometer experimental results and was used to predict metal ion release from CoCrMo alloy heads in MoP hip joints. The results showed correspondence between model predicted wear accelerated corrosion and literature reported material loss of CoCrMo alloy heads in MoP hip joints tested using hip joint simulators. This model provides a tool to predict the level of metal ions released from MoP hip joints and has the potential to be used by medical doctors to evaluate the risk of adverse reactions for patients planned to receive a MoP hip implant.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552881","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}

{"title":"A Coarse Grained Molecular Dynamics Model for the Simulation of Lubricating Greases","authors":"Anthony Benois,&nbsp;Sebastián Echeverri Restrepo,&nbsp;Nicola De Laurentis,&nbsp;Femke Hogenberk,&nbsp;Andrea Giuntoli,&nbsp;Piet M. Lugt","doi":"10.1007/s11249-024-01878-w","DOIUrl":"10.1007/s11249-024-01878-w","url":null,"abstract":"<div><p>The rheological properties of lubricating greases are determined by the viscosity of the base oil, the interaction between base oil and thickener, and the interaction between thickener particles. The contribution of the oil–thickener interactions to the viscosity is well known, but the contribution of the thickener–thickener interactions has not yet been studied by employing theoretical or computational frameworks. In this paper, we use coarse-grained molecular dynamics to simulate a fibrous microstructure, and we show that the experimentally observed viscoelastic/plastic behaviour can be well reproduced. A parametric study shows that the apparent viscosity increases with increasing fibre length, fibre stiffness and thickener concentration. This is as expected, showing that this modelling approach is useful to study effects on grease rheology that are not accessible experimentally, such as impact of fibre entanglement or agglomeration.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-024-01878-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-Situ Observation and Discrete Element Simulation of Solid Graphite Lubrication Mechanism","authors":"Junchao Kong,&nbsp;Qiangqiang Zhang,&nbsp;Bing Xu,&nbsp;Gang Wang,&nbsp;Huifang Dong","doi":"10.1007/s11249-024-01881-1","DOIUrl":"10.1007/s11249-024-01881-1","url":null,"abstract":"<div><p>Solid lubrication is a green manufacturing technology with high efficiency, which saves energy and material and thus it is suitable for extreme conditions in mechanical engineering fields such as aerospace and high temperature mold. In this study, a graphite layer of specified thickness was prepared on the end face of the upper specimen by the directional spray method. The effect of velocity and load on the friction characteristics of the graphite layer were investigated using a friction tester capable of real time observation of the friction interface. Subsequently, a 3D surface profilometer, SEM, and EDS were used to characterize the morphology and elemental composition of the worn surfaces. The results show that the lubrication performance of the graphite layer is most effective with a flatter worn surface (S_a and S_Z are smaller) and higher carbon content when the velocity is 12.5 mm/s and the load is 4N. Meanwhile, force chains are short, numerous and lasting for a long time, while being uniformly distributed in all directions and velocity fluctuates greatly, with slowly decreased coordination numbers. This study aims to provide a reasonable explanation for the mechanisms by which velocity and load influence the lubrication effect of the powder layer.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513692","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}

{"title":"An Analysis of Shear-Dependent Mechanochemical Reaction Kinetics","authors":"Resham Rana,&nbsp;Nicholas Hopper,&nbsp;François Sidoroff,&nbsp;Juliette Cayer-Barrioz,&nbsp;Denis Mazuyer,&nbsp;Wilfred T. Tysoe","doi":"10.1007/s11249-024-01879-9","DOIUrl":"10.1007/s11249-024-01879-9","url":null,"abstract":"<div><p>This paper shows how the effect of combined normal and shear stresses on the rates of tribochemical reactions can be calculated using Evans-Polanyi (E-P) perturbation theory. The E-P approach is based on transition-state theory, where the rate of reaction is taken to be proportional to the concentration of activated complex. The equilibrium constant depends on the molar Gibbs free energy change between the initial- and transition-states, which, in turn, depends on the stresses. E-P theory has been used previously to successfully calculate the effects of normal stresses on reaction rates. In this case, ln(Rate) varies linearly with stress with a slope given by an activation volume, which broadly corresponds to the volume difference between the reactant and activated complex. An advantage of E-P theory is that it can calculate the influence of several perturbations, for example, the normal stress dependence of the shear stress during sliding. In this paper, E-P theory is used to calculate shear-induced, tribochemical reaction rates. The results depend on four elementary activation volumes for different contributions to the Gibbs free energy: two of them due to normal and shear stresses for sliding over the surface and two more for the surface reaction. The results of the calculations show that there is a linear dependence of ln(Rate) on the normal stress but that the coefficient of proportionality between the ln(Rate) and the normal stress now has contributions from all elementary-step activation volumes. Counterintuitively, the analysis predicts that the ln(Rate)-normal stress evolution tends, at zero normal stress, to an asymptotic rate constant that depends on sliding velocity and differs from the thermal reaction rate. The theoretical prediction is verified for the shear-induced decomposition of ethyl thiolate species adsorbed on a Cu(100) single crystal substrate that decomposes by C‒S bond cleavage. The theoretical analyses show that tribochemical reactions can be influenced by either just normal stresses or by a combination of normal and shear stresses, but that the latter effect is much greater. Finally, it is predicted that there should be a linear relationship between the activation energy and the logarithm of the pre-exponential factor of the asymptotic rate constant.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141350477","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}

{"title":"Temperature Measurements at Tyre Tread Rubber on Sandpaper Oscillatory Sliding Contacts Using Acicular Grindable Thermocouples","authors":"Oleksii Nosko,&nbsp;Yurii Tsybrii,&nbsp;Pablo Guillermo Torrelio Arias,&nbsp;Adolfo Senatore","doi":"10.1007/s11249-024-01877-x","DOIUrl":"10.1007/s11249-024-01877-x","url":null,"abstract":"<div><p>The tribological performance of tyre–road contacts depends crucially on the contact temperature. This study investigates the reliability and accuracy of acicular grindable thermocouples possessing an original needle-shaped wearable part as applied to measuring temperature at the oscillatory sliding contact between a rubber tyre tread sample and a sandpaper. A linear oscillatory tribometer is used to imitate the sliding phase of tyre–road contact under mild friction conditions. It is shown that the acicular grindable thermocouple measurements are generally test–retest repeatable. Moreover, the thermocouple signal becomes more stable with increasing contact pressure. Compared to the conventional thermocouple technique, the acicular grindable thermocouple overestimates temperature at the rubber friction surface by about 23% due to involvements of its wearable part in friction with the sandpaper. The findings suggest an expansion of the acicular grindable thermocouple technique to full-scale experiments with tyres on the road.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-024-01877-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141357492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Additives Depletion by Water Contamination and Its Influences on Engine Oil Performance","authors":"A. Al Sheikh Omar,&nbsp;F. Motamen Salehi,&nbsp;U. Farooq,&nbsp;A. Morina","doi":"10.1007/s11249-024-01876-y","DOIUrl":"10.1007/s11249-024-01876-y","url":null,"abstract":"<div><p>Water enters engine oil in different ways and moves in the lubrication system causing an increase in wear, oil degradation and additives depletion. It has been proposed that water in the lubricants can transfer from dissolved to free phase leading to additives depletion in the oil. Different additives in the lubricants can easily latch to water molecules forming reverse micelles. The separation of reverse micelles from the oil causes additives depletion. This experimental and analytical study aims to investigate how the separation of free water above the saturation level can diminish the efficiency of additives in engine oils. The effect of varied levels of water on oil performance and its additives was investigated in this study. A new saturation method was used to determine the water saturation level in engine oil at different temperatures. The results reveal a decrease in additive concentration with increased separation of free water from the oil. Free water separation from engine oil is expected to reclaim the tribological performance, however, the results demonstrate that tribological performance after the separation of free water from the oil has been affected. The study showed not only does the removal of free water diminish the efficiency of additives due to additives depletion (≈ 10 wt%), but also the remaining dissolved water which is ≈ 2600 ppm can also affect wear and tribofilm chemistry. The results prove that two main mechanisms influence oil performance expressed as additives depletion by free water and remaining dissolved water.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-024-01876-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141365302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coarse-Grained Molecular Dynamics Simulations of Nanoscale Roughness Effects on Oil Film Delamination","authors":"Shizhe Deng,&nbsp;Atsushi Kubo,&nbsp;Yoshikazu Todaka,&nbsp;Yoshinori Shiihara,&nbsp;Masatoshi Mitsuhara,&nbsp;Yoshitaka Umeno","doi":"10.1007/s11249-024-01872-2","DOIUrl":"10.1007/s11249-024-01872-2","url":null,"abstract":"<div><p>In boundary lubrication, the detachment of lubricant molecules from a solid surface is likely to occur due to the presence of high compressive normal stress combined with shear stress exerted on the solid–liquid interface. This phenomenon often results in a delamination behavior at the interface. We aim to investigate the nanoscale roughness effect on the oil film delamination from sliding iron surfaces with grain boundaries by coarse-grained molecular dynamics simulations. As a result, the oil film delamination was effectively suppressed in higher roughness. Two distinct mechanisms of delamination were found depending on surface roughness when the critical normal stress is exceeded. High roughness enhanced the ability to prevent complete slip but had negligible influence on partial slip.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-024-01872-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141368531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thickener Behaviour in Rolling Elastohydrodynamic Lubrication Contacts","authors":"Michal Okal,&nbsp;David Kostal,&nbsp;Kazumi Sakai,&nbsp;Ivan Krupka,&nbsp;Martin Hartl","doi":"10.1007/s11249-024-01874-0","DOIUrl":"10.1007/s11249-024-01874-0","url":null,"abstract":"<div><p>This paper focuses on the study of thickener behaviour in elastohydrodynamic contacts using fluorescence microscopy and optical interferometry. A standard Ball-on-disc configuration tribometer was used as well as a newly developed Ball-on-ring configuration tribometer mimicking the conditions in a 6314 deep groove ball bearing. Three types of custom-made greases were used with the same base oil and Coumarin 6 fluorescent dye on the thickener. These greases contained no additives and were of the lithium complex and alicyclic di-urea type. It was confirmed that the behaviour of the grease was directly influenced by both the structure and type of thickener, and the differences were successfully observed by fluorescence microscopy. The concentration of thickener was found to change due to the formation or breakdown of the deposited thickener layer on the track. At low speeds, the alicyclic di-urea forms a thickener layer on the track that is more pronounced than the lubricating film formed by the base oil alone. The thickener layer formation also occurs at higher speeds when fully flooded conditions are beneficial in building the layer. Experiments with a Ball-on-ring tribometer show that the natural replenishment of the real contact geometry is more effective than on a Ball-on-disc tribometer, but the formation of the thickener layer on the track is more limited than in a Ball-on-disc tribometer with artificial replenishment. At higher velocities, a smaller but stable layer is formed where the layer does not change much from a certain velocity.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-024-01874-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141257423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the Friction Behavior and Abnormal Conditions of Non-contact Mechanical Seal Based on Acoustic Emission","authors":"Jinxin Chen,&nbsp;Junjie Lu,&nbsp;Yaochun Hou,&nbsp;Xuexing Ding,&nbsp;Wei Zhang","doi":"10.1007/s11249-024-01873-1","DOIUrl":"10.1007/s11249-024-01873-1","url":null,"abstract":"<div><p>The main cause of failure in sealing friction pairs, friction wear, has presented analytical challenges due to rapidly changing and complex friction frequency characteristics. This has led to a focus on surface morphology treatment rather than direct measurement techniques in research. In this context, the present study adopted Acoustic Emission (AE) technology for direct monitoring of friction pairs, aiming to identify friction response signals during their transient contact and abrasion stages. Employing time–frequency analysis, the research delineated the state evolution of AE characteristics during the entire operational cycle of the friction pair, from start to stop. It has established the time–frequency information of AE signals in relation to the surface state of the sealing friction pair and deciphered the correlation between the friction AE signals and the surface state alterations of the friction pair. The study showed that the frequency of friction-induced signals in seals is 270 ± 40 kHz. The transition speeds for the friction pair’s state, moving from boundary lubrication to mixed lubrication and then to fluid dynamic lubrication, were identified as 200 rpm and 1000 rpm, respectively. Additionally, an escalation in signal activity was observed in dry friction scenarios and when surface defects were present in the friction pair, markedly exceeding the activity in conditions of no wear. This relationship between the friction signals and the operational state of the seal facilitates precise assessments of wear and operational integrity, underpinning the theoretical aspects of periodic wear in seal tribology.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141257599","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}