Tribological Factors Research Articles

A Review on Tribological Considerations in the Transition from IC Engines to Electric Vehicles

The shift from internal combustion (IC) engines to electric vehicles (EVs) marks a significant transformation in the automotive industry, prompting a comprehensive reassessment of various engineering considerations. Among these, tribological factors play a critical role in ensuring the performance, reliability, and longevity of vehicle components. This review examines the tribological challenges and opportunities posed by the transition to EVs, focusing on key components such as bearings, gears, and braking systems, which face unique operating conditions in electric powertrains compared to their IC counterparts. The paper addresses how electric vehicles encounter distinct tribological scenarios, such as lower operating temperatures but higher torque loads, which demand new materials and lubrication strategies. It also explores how the near absence of internal combustion in EVs affects component wear and the mechanisms of friction reduction. Additionally, the tribological challenges in IC engines are revisited to provide a comparative understanding of how they differ from those in EVs, particularly regarding energy efficiency and frictional losses. This review emphasizes the importance of minimizing wear and friction to maximize energy efficiency, which is crucial for extending vehicle range and improving performance in EVs. By synthesizing the latest research findings and industry advancements, the review offers valuable insights for researchers and engineers involved in the design and optimization of tribological systems for the next generation of electric vehicles.

Thermal kinetic, mechanical and wear properties of glass fiber reinforced polyamide 6 thermoplastic composites

AbstractPolyamide 6 (PA6) thermoplastic‐based composites are often used in automobile, aerospace, marine, and biomedical applications. Here, PA6 and its composites with varied chopped glass fiber (GF) concentrations of 5, 10, and 20 mass% were fabricated by injection molding. The specimens were characterized by structural, thermal kinetic, mechanical, as well as tribological analyses. Tribological performance was evaluated in dry pin‐on‐disc test apparatus with three different levels of time, speed, and load factors. The PA6/GF composites showed high decomposition activation energy compared to pure PA6. Thermal activation, Ea increased to 46.16% with increasing of GF content up to 10 mass% in the composites compared to PA6. PA6/5GF exhibited best mechanical properties (e.g., strength = 44.46 MPa and Hardness = 45.2). Addition of GF in PA6 significantly improved tribological properties, coefficient of friction (COF) and specific wear rate (WR) besides thermal stability and mechanical properties of the composites. Especially, COF and WR of PA6/5GF composite decreased by 17%–65% and 68%–92%, respectively, compared to PA6. ANOVA statistical results determined the significant contribution of the tribological factors to the performance metrics of the composites for COF and WR. Therefore, the PA6/5GF composite would highly be useful for tie‐rod gears and bearings as a crucial structural component in automotive bodywork.

Tribological study of magnesium-based AZ91/TiC/rGO hybrid composite prepared by powder metallurgy route: an experimental and analytical approach

ABSTRACT In this research, hybrid composites of magnesium alloy (AZ91) reinforced with titanium carbide (TiC) and reduced graphene oxide (rGO) were studied. The powder metallurgy method was used to synthesise magnesium alloy-based hybrid composites. The tribological behaviour of fabricated composite samples was examined using a pin-on-disc tribotester per the ASTM G99 standard. Using the Taguchi method, the design of the experiment (DOE) was constructed. The L9 orthogonal array opted for tribo-performance evaluation. Also, an ANOVA and regression analysis were carried out to ascertain the relative impact of the tribological factors on the responses. In the present investigation, three variable factors were considered, i.e. reinforcement percentage of TiC (0–10%) keeping constant 0.5 wt.% rGO, disc sliding velocity (0.5 to 1.5 m/s), and applied load varies between 10 and 30 N. It was found that the load parameter had a considerable impact on both the wear rate (WR) and the coefficient of friction (COF). Sliding velocity, on the other hand, had a minimal effect on WR. The concentration of reinforcement exhibits a moderate effect. Taguchi’s predictive results were also compared with experimental results. The worn surfaces were analysed using scanning electron microscopy (SEM), and surface roughness was used for wear mechanics analysis.

Exploring tribology and material contact science in spine surgery: implications for implant design.

Tribology, an interdisciplinary field concerned with the science of interactions between surfaces in contact and their relative motion, plays a well-established role in the design of orthopedic implants, such as knee and hip replacements. However, its applications in spine surgery have received comparatively less attention in the literature. Understanding tribology is pivotal in elucidating the intricate interactions between metal, polymer, and ceramic components, as well as their interplay with the native human bone. Numerous studies have demonstrated that optimizing tribological factors is key to enhancing the longevity of joints and implants while simultaneously reducing complications and the need for revision surgeries in both arthroplasty and spinal fusion procedures. With an ever-growing and diverse array of spinal implant devices hitting the market for static and dynamic stabilization of the spine, it is important to consider how each of these devices optimizes these parameters and what factors may be inadequately addressed by currently available technology and methods. In this comprehensive review, the authors' objectives were twofold: 1) delineate the unique challenges encountered in spine surgery that could be addressed through optimization of tribological parameters; and 2) summarize current innovations and products within spine surgery that look to optimize tribological parameters and highlight new avenues for implant design and research.

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

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.

Utilizing design of experiments techniques to determine the optimal coefficient of friction in spur gears

The friction occurring between the teeth of gears is a significant contributor to energy loss in gear drives. Factors like the load, speed, and coefficient of friction (µ) play a crucial role in determining the extent of frictional losses in gears. The coefficient of friction (µ) is a complex function influenced by various tribological parameters, including rolling, and sliding velocities, normal load at the tooth contact zone, oil temperature, and contact surface roughness. To analyze the impact of design and operating parameters on the coefficient of friction, a comprehensive statistical parametric approach was employed, combining numerical and statistical methods. The study employed a design of experiments methodology to numerically examine the impact of various tribological factors on the coefficient of friction. This methodology facilitated the identification of primary effects and crucial factors that have a significant impact on the variable µ. The findings derived from the computational models were subsequently compared with the discoveries of pre-existing investigations that includes both experimental and theoretical approaches. The proposed method represents a powerful tool for understanding the relationship and correlation between major tribological factors and the coefficient of friction. By employing this approach, it becomes possible to identify optimized tribological parameters. This information is valuable in improving the design and operation of gear systems, with the aim of reducing energy loss due to friction and enhancing overall efficiency.

Influence of Physical Activity and Cup Orientation on Metal Ion Release and Oxidative Stress in Metal-on-Metal and Ceramic-on-Metal Total Hip Arthroplasty.

Metal-on-metal (M-M) total hip arthroplasty (THA) has shown adverse reactions to metal debris, abnormal soft-tissue reactions, and high blood metal ion levels. This study aims to: (1) assess whether the toxicity of high levels of ions is related to altered oxidative stress and (2) evaluate tribological factors related to increased blood levels of chromium (Cr) and cobalt (Co) ions. A cross-sectional analytical descriptive study was conducted on 75 patients. A total of 25 underwent M-M THA, 25 ceramic-on-metal (C-M) THA, and 25 were on the THA waiting list. Ion metallic levels in blood, oxidative stress, physical activity, and implant position were compared. In the M-M group, Co and Cr levels were significantly higher than those found in the C-M group and the control group (p < 0.01). We found no differences in terms of oxidative stress between the groups. Also, we did not find a correlation between metal blood levels and oxidative stress indicators, the physical activity of the patients or the position of the implants between groups. The use of M-M bearing surfaces in THA raises the levels of metals in the blood without modifying oxidative stress regardless of the physical activity levels of the patients. Therefore, although patients with M-M bearings require close monitoring, it does not seem necessary to recommend the restriction of physical activity in patients with M-M or C-M arthroplasties.

The Influence of the Geometry of Movement during the Friction Process on the Change in the Tribological Properties of 30CrNiMo8 Steel in Contact with a G40 Steel Ball.

Experiments with changes in motion geometry can provide valuable data for engineering and development purposes, allowing a better understanding of the influence of tribological factors on the performance and service life of joints. The presented subject article focused on the experimental investigation of the influence of the geometry of the movement of the friction process on the change in the tribological properties of 30CrNiMo8 steel. The friction process was carried out without the use of a lubricant in contact with a steel ball of G40 material with a diameter of 4.76 mm. The steel ball performed two types of movement on the surface of the experimental material. The first method used was ball on disc, in which the ball moved reciprocally in an oval direction at an angle of 180° on a circumferential length of 35 mm at a speed of 5 mm/s. The second method consists of the same input parameters of the measurement, with the difference that the path along which the ball moved had a linear character. The load during the experiment was set at a constant value of 50 N with 1000 repetitions. The results show that with the ball on disc method, there was an increase in wear by 147% compared to the linear test method, which was approximately a coefficient of increase in wear of 2.468. EDS analysis pointed to the occurrence of oxidative wear that affected the resulting COF values, which were lower by 8% when using the ball on disc method due to a more uniform distribution of O and C on the surface of the friction groove where these elements acted as solid microlubricants. With the ball on disc method, defects in the form of microcracks occurred, which affected the reduction in the values of the depth of the affected area of microhardness.

Biotribology in the Cognitive Domain: Investigation of the Neural Response to a Textured Tactile Stimulus using Event-Related Potentials (ERP)

Tactile communication tools such as tactile graphics and braille used by the blind and visually impaired (BVI) rely on the sense of touch to convey information. Limitations in the skin's perceptive resolution and inefficiencies in the representation of tactile information within a modest amount of page space pose challenges in representing scientific information such as those commonly encountered in the STEM fields. To overcome such limitations, the tribological factors affecting perception and the subsequent quantification of perception using a reliable metric unaffected by subjectivity are essential. In this study, direct observation of the neural activity in response to a tactile stimulus using event-related potentials (ERP) is presented, and its viability to consistently quantify the neural activity and locate the cortical regions involved in tactile stimulus processing has been investigated. A control sample with no textures and a textured sample that presents a change from smooth to rough textures were used as stimuli. The ERP data were collected using a 64-electrode electroencephalography (EEG) system. A squared difference approach was used to measure the differences in the electric potential amplitude caused by the control sample and the textured sample. The primary somatosensory cortex (SI) and posterior parietal cortex (PPC) of the brain showed persistent activity, suggesting that these areas were frequently involved in processing the tactile stimulus used in this study. Surprising results were observed when the temporal cortex and inferior parietal cortex (IPC) that have not been previously shown to be involved in processing tactile stimulations also showed persistent activity. However, their proximity to the primary somatosensory cortex and posterior parietal cortex suggests that areas adjacent to these cortices might also be involved in tactile stimulus processing. Overall, the analysis results showed that ERP could be used as a quantitative and objective tool in studying the cognitive response to tactile stimuli.

Experimental Investigation and Machine Learning Modeling of Wear Characteristics of AZ91 Composites

Abstract This study's primary goal is to examine the effects of wear parameters on the wear-rate (WR) of magnesium (AZ91) composites. The composites are made up of using a stir casting process with aluminum oxide (Al2O3) and graphene as reinforcements. In the present work, one material factor (material type (MT)) and three tribological factors (load(L), velocity (V), and sliding distance (D)) were chosen to study their influence on the wear-rate. Taguchi technique is employed for the design of experiments, and it was observed that load (L) is the most influencing parameter on WR, followed by MT, D, and V. The optimal values of influencing parameters for WR are as follows: MT = T2, L = 10 N, V = 2 m/s, and D = 500 m. The wear mechanisms at the highest and lowest WR conditions were also studied by observing their scanning electron micrographs (SEM) on wear pin’s surface and its debris. From the SEM analysis, it was observed that abrasion, delamination, adhesion, and oxidation mechanisms were exhibited on the wear surface. Machine learning (ML) models such as artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and decision tree (DT) were used to develop an effective prediction model to predict the output responses at the corresponding input variables. Confirmation tests were conducted under optimal conditions, and the same were examined with the results of ANN, ANFIS and DT. It was noticed that the DT model exhibited higher accuracy when compared to other models considered in this study.

Influence of TiN Coating on the Drawing Force and Friction Coefficient in the Deep Drawing Process of AlMg4.5Mn0.7 Thin Sheets.

The influence of various process parameters on the deep drawing process is a current research topic in sheet metal forming technology. Starting from the application of the previously constructed original testing device, an original tribological model was developed based on the process of sheet metal strip sliding between flat contact surfaces under variable pressures. A complex experiment was executed using an Al alloy sheet, tool contact surfaces of different roughness, two types of lubricants and variable contact pressures. The procedure included analytically pre-defined contact pressure functions based on which, for each of the mentioned conditions, the dependencies of the drawing forces and friction coefficients were obtained. The pressure in function P1 constantly decreased from a high initial value until the minimum, while in function P3 the pressure increased until the minimum value at the halfway point of the stroke, after which it increased up to the initial value. On the other hand, the pressure in function P2 constantly increased from the initial minimum value until the maximum value, while in function P4 the pressure increased until reaching the maximum value at the halfway point of the stroke, after which it decreased to the minimum value. This enabled the determination of the influence of tribological factors on the process parameters of intensity of traction (deformation force) and coefficient of friction. The pressure functions starting with decreasing trends produced higher values for the traction forces and the friction coefficient. In addition, it was established that the roughness of the contact surfaces of the tool, especially those with titanium nitride coating, has a significant influence on the process parameters. For surfaces of lower roughness (polished), a tendency of the Al thin sheet to form a glued-on layer was noticed. This was especially prominent for lubrication with MoS2-based grease under conditions of high contact pressure (functions P1 and P4 at the beginning of the contact).

A Study on Outstanding High‐Temperature Wear Resistance of High‐Entropy Alloys

Wear property is a main reason for failure, especially for those parts which are mechanically moving and interacting with each other in industrial utilization. High‐entropy alloys (HEAs) are considered promising candidates to possess outstanding tribological factors of performance at high temperatures compared with conventional engineering alloys, which have drawn much attention from academic and industrial points of view. This study is performed to survey the influence of microstructure, grain size, precipitation, reinforcement, and elements addition on the wear resistance of HEAs over a wide temperature range. In this respect, the worn microstructure, wear rate, friction coefficient, hardness, wear track, and subsurface are precisely checked. This review also explores the high‐temperature wear resistance of thermally sprayed and additively manufactured HEAs associated with emphasizing the dominant wear mechanisms through in a wide range of temperatures.

Multi-performance optimization of the diamond burnishing process in terms of energy saving and tribological factors

Surface characteristics can be improved using diamond burnishing. In this work, an ecological indicator (energy efficiency- EF) and tribological factors (the coefficient and friction- COF and specific wear rate- SWR) of a single diamond burnishing process were optimized. The process parameters were the burnishing speed ( V), burnishing depth ( D), feed rate ( f), the diameter of the tip ( DT), and initial average roughness ( IR). An efficient cooling-lubrication device comprising the minimum quantity lubrication and Ranque–Hilsch vortex tubes was utilized to facilitate burnishing trials. The Kriging models of burnishing performances were developed regarding parameters. The CRITIC method, Crow Search Algorithm, and TOPSIS were employed to select weights and optimality. The optimizing outcomes indicated that optimal values of the V, D, f, DT, and IR were 160 m/min, 0.10 mm, 0.05 mm/rev., 7 mm, and 2.00 μm, respectively. The EF was improved by 34.1%, while the COF and SWR were decreased by 33.2% and 8.1%, respectively. The optimal data could be applied to practical diamond burnishing to improve energy efficiency and tribological parameters for burnished external surfaces. The optimizing technique comprising the Kriging models, CRITIC, Crow Search Algorithm, and TOPSIS could be efficiently utilized to solve complex issues for burnishing operations and other machining processes. A developed system could be applied to enhance cooling-lubrication efficiencies for different machining operations, such as turning, milling, and grinding processes.

A Comparative Review of Thermocouple and Infrared Radiation Temperature Measurement Methods during the Machining of Metals.

During the machining process, substantial thermal loads are generated due to tribological factors and plastic deformation. The increase in temperature during the cutting process can lead to accelerated tool wear, reducing the tool’s lifespan; the degradation of machining accuracy in the form of dimensional inaccuracies; and thermally induced defects affecting the metallurgical properties of the machined component. These effects can lead to a significant increase in operational costs and waste which deviate from the sustainability goals of Industry 4.0. Temperature is an important machining response; however, it is one of the most difficult factors to monitor, especially in high-speed machining applications such as drilling and milling, because of the high rotational speeds of the cutting tool and the aggressive machining environments. In this article, thermocouple and infrared radiation temperature measurement methods used by researchers to monitor temperature during turning, drilling and milling operations are reviewed. The major merits and limitations of each temperature measurement methodology are discussed and evaluated. Thermocouples offer a relatively inexpensive solution; however, they are prone to calibration drifts and their response times are insufficient to capture rapid temperature changes in high-speed operations. Fibre optic infrared thermometers have very fast response times; however, they can be relatively expensive and require a more robust implementation. It was found that no one temperature measurement methodology is ideal for all machining operations. The most suitable temperature measurement method can be selected by individual researchers based upon their experimental requirements using critical criteria, which include the expected temperature range, the sensor sensitivity to noise, responsiveness and cost.

Tribocorrosion of Dental Implants A Systematic Review

Objective: This systematic review seeks to analyze the impact of the concentration, size, and location of corrosion particles on oral tissues and different surface treatments of implants to increase their durability in the oral cavity. Methodology: An electronic search was conducted using the database of PubMed. In addition, manual search of the papers cited in relevant studies was also undertaken. Only human studies published in the last decade were included. Conclusion: This study concluded that apart from established functional and metabolic factors, implants also undergo wear and tribocorrosion when subjected to the oral environment. These tribological factors not only contribute to the eventual failure of implants but also instigate certain biological responses. Keywords: Corrosion, Allergy, Hypersensitivity, Implant, Dental Implant

IMPLICAÇÃO DE ANÁLISES TRIBOLÓGICAS NA REALIZAÇÃO DA MANUTENÇÃO PREDITIVA

In predictive maintenance, interventions are dependent on information from the monitoring of parameters, their main advantage is the reduction of periodic stops, increasing the time of availability of equipment and decreasing costs. Subjects such as wear, lubrication and surfaces with relative movement are studied by tribology. The purpose of this article was to investigate the relationship between tribology and predictive maintenance. The basis for scientific foundation was bibliographic research in studies by different authors. Thus, it is concluded that tribology has significant relevance in performing predictive maintenance, especially in view of the analysis of lubricating oil and wear of particles. These analyzes and correct implementation were considered, being a fundamental point for companies that seek to increase their competitiveness. However, scarcity was observed in practical case studies, which demonstrates that the relationship between maintenance and tribological factors needs to be studied more deeply.

Rheological and tribological characterization of novel modified graphene/oil-based nanofluids using force microscopy.

In this study, it is aimed to improve the lubrication and anti-wear characteristics of nanofluids produced by the distribution of silane-modified graphene nanosheets into the base oil without any surfactant or dispersant. Nanofluids are among the hottest research topics currently studied in the literature due to their interesting thermal and rheological properties. Graphene nanosheet with unique physicochemical properties is a good alternative as a nanofluid component and a lubricant. In this study, the behavior of nanofluidic films on the material was investigated by using scanning probe techniques, phase-contrast microscopy, and friction force microscopy techniques. Due to stick-slip behavior and rheological properties that are dominant in the studied ranges, problems were encountered in performing tribological analyzes with friction force microscopy. On the other hand, these results have been beneficial in determining tribological factors in nanoscale. The presented nanofluids showed non-Newtonian behavior at high concentrations and shear rates and shown an improved tribological performance up to 43% in friction coefficient, 91% in wear, and 46% in thermal conductivity compared to the base oil.

Anti-diabetic (AD) and hardness profile of 12-(4-Chlorophenyl)-9,9- Dimethyl-9,10-Dihydro-8H-benzo[a]xanthen-11(12H)-one –(CPDDHBXH) – Comparative analysis of macro and nano crystals

As the CPDDHBXH full scale and nano crystals are having gargantuan effect on opto-electronic applications, stage coordinating, recurrence coordinating and power transmission and different sorts of utilities in bio and with drug store fields, it is the extent of the physicists and electronic friends to create and consider the exceptional capacities like nano tribological factors and different utilities. Full scale crystals have littlest sum pertinent relationships by estimation disparity to nano outline of CPDDHBXH equipped by mill recital. The nano form of CPDDHBXH crystals are of 22 nm respectively, the XRD data reveals the macro crystals are having the formula C25H21ClO2 are of a = 10.293 Å, b = 11.621 Å, c = 16.447 Å, β = 90.04°, monoclinic with space group P21 /n, the macro level NLO is nearly 2 times higher than that of typical KDP. Here, both the macro and nano crystals are undergone with AD work and hardness profile studies and reported, CPDDHBXH are best for electronic filters and for frequency converters stand on their macro stage NLO-SHG efficiency.

Fluorescence, filter,nano tribological studies of 12-(4-Chlorophenyl)-9,9-Dimethyl-9,10-Dihydro-8H-Benzo[A]Xanthen-11(12H)-One – (CPDDHBXH) macro and nano crystals

As the CPDDHBXH macro and nano crystals are having immense impact on opto-electronic applications, phase matching, frequency matching and power transmission and other types of utilities in bio and with pharmacy fields, it is the scope of the physicists and electronic peers to develop and study the special functions like nano tribological factors and other utilities. Macro crystals have smallest amount relevances by estimation dissimilarity to nano silhouette of CPDDHBXH prepared by milling performance. The nano form of CPDDHBXH crystals are of 22 nm respectively, the XRD data reveals the macro crystals are having the formula C25H21ClO2 are of a = 10.293 Å, b = 11.621 Å, c = 16.447 Å, β = 90.04°, monoclinic with space group P21/n, the macro level NLO is 1.96 times higher than that of typical KDP. Here, both the macro and nano crystals are undergone with filter, fluorescence and tribological studies and reported, CPDDHBXH are best for electronic filters and for frequency doublers based on their macro level NLO-SHG efficiency.

Tribological, Filter, FTIR and fluorescence studies of L-Alaninium tartrate (LAT) Macro and nano crystals

As the LAT macro and nano crystals are having massive brunt on opto-electronic applications, stage matching, frequency matching and power transmission and other sorts of utilities in bio and with pharmacy fields, it is the scope of the physicists and electronic peers to develop and study the special functions like nano tribological factors and other utilities. Macro crystals have smallest amount relevances by estimation dissimilarity to nano silhouette of LAT prepared by milling performance. The nano form of LAT crystals are of 20 nm respectively, the XRD data reveals the macro crystals are having the formula C7H13NO8 are of a = 5.1446 Å, b = 13.721 Å, c = 7.4750 Å, β = 98.09°, monoclinic with space group P21, the macro level NLO is 1.2 times higher than that of typical KDP. Here, both the macro and nano crystals are undergone with filter, fluorescence and tribological studies and reported, LAT are best for electronic filters and for frequency doublers based on their macro level NLO-SHG efficiency.