Lubrication Failure Research Articles

Investigating the Influence of Protic Ionic Liquid on the Triboelectrical Properties of Trimethylolpropane Trioleate (TMPO)

Under triboelectric conditions, where tribocharging accelerates lubrication failure, lubricants with enhanced electrical properties are essential. Trimethylolpropane Trioleate (TMPO) oil, derived from esters that possess good lubricating properties and wear performance but is lacking in terms of electrical properties which can be further improved when blended with Ionic Liquid. This study blends 1 – 5 wt% of Protic Ionic Liquid (PIL) into TMPO and evaluate the frictional and wear performances of the blends under 1 – 2 A current conditions to understand the behaviour towards the tribological properties of different blends of material. Electric currents ranging around 1 – 2 A are implemented to the custom-designed ball-on-disc tribometer, with a constant 4.5 V voltage supply and the static resistance are measured. Mechanical wear properties are observed after the tribological test with different samples. The frictional properties of all concentrations of PIL in TMPO showed significant frictional improvements with 1%wt PIL showed 53% better results indicating improvements in frictional properties and wear performance under 2A current conditions, owing to its lowest film resistivity of 0.14 mΩ.

A general strategy for developing eco-friendly, harsh condition adaptive, and friction tunable supramolecular gel lubricants via hydrogen bonding interaction

As green tribology and controllable lubrication technology progress, traditional lubricants fail to meet the evolving requirements of environmental sustainability, adaptability to extreme conditions, and precise friction coefficient control. In this work, a general strategy is proposed to obtain eco-friendly, harsh condition adaptive, and friction tunable polyol supramolecular gel lubricants. Molecular dynamics simulations reveal that the formation of supramolecular gels is induced by the hydrogen bond interaction between PVA, MXene, and polyols. Rheological tests demonstrate the excellent shear thinning and creep recovery properties of the prepared supramolecular gel at both room and low temperatures, positioning it as a promising new lubricant. Tribological tests further show that the supramolecular gel achieved a low friction coefficient of 0.056 and a wear rate as low as 1.88 × 10−9 mm3 N−1 m−1. Moreover, the tribological properties of various polyol supramolecular gels were compared and the viscosity-controlled friction lubrication behavior was observed. This research not only presents a novel strategy for developing environmentally friendly supramolecular gel lubricants that are adaptable to harsh conditions and tunable in friction, but also offers practical solutions to address challenges such as environmental pollution, lubrication failures in extreme environments, and precise friction control.

Attribute-driven fuzzy fault tree model for adaptive lubricant failure diagnosis

Attribute-driven fuzzy fault tree model for adaptive lubricant failure diagnosis

Effect of phosphide additives on the tribological properties of polyethylsiloxane (PES) in Si3N4 and M50 system

PurposeThe incorporation of phosphide additives is regarded as a highly effective strategy for enhancing the lubricative qualities of base oils. This study aims to assess the lubrication behavior and efficacy of various phosphide additives in polyethylsiloxane (PES) through the employment of the Schwingum Reibung Verschleiss test methodology, across a temperature range from ambient to 300°C.Design/methodology/approachPES demonstrated commendable lubrication capabilities within the Si3N4/M50 system, primarily attributable to the Si-O frictional reaction film at the interface. This film undergoes disintegration as the temperature escalates, leading to heightened wear. Moreover, the phosphide additives were found to ameliorate the issues encountered by PES in the Si3N4/M50 system, characterized by numerous boundary lubrication failure instances. A chemical film comprising P-Fe-O was observed to form at the interface; however, at elevated temperatures, disintegration of some phosphide films precipitated lubrication failures, as evidenced by a precipitous rise in the coefficient of friction.FindingsThe results show that a phosphide reactive film can be formed and a reduction in wear rate is achieved, which is reduced by 64.7% from 2.98 (for pure PES at 300°C) to 1.05 × 10–9 μm3/N m (for triphenyl phosphite at 300°C).Originality/valueThe data derived from this investigation offer critical insights for the selection and deployment of phosphide additives within high-temperature lubrication environments pertinent to PES.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0139/

Tribological properties and wear mechanism of Ag@Ti3C2Tx phosphate coatings from room temperature to 800 °C

MXene, a novel two-dimensional layered material, finds extensive applications in solid lubrication. However, its practical use is limited by lubrication failures at high temperatures. To increase the service temperature of Ti3C2Tx solid lubricants, phosphate lubricating coatings were prepared using Ag@Ti3C2Tx as solid lubricants, which exhibits superior tribological properties. Compared with Ti3C2Tx phosphate coating, the friction coefficient and wear rate of Ag@Ti3C2Tx phosphate coating significantly decrease between 400 °C and 800 °C. Especially at 800 ℃, the friction coefficient of Ag@Ti3C2Tx phosphate coating reaches 0.09, and the wear rate shows extremely low. This study lays the foundation for the application of Ti3C2Tx in the field of solid lubricants across a wide temperature range.

Thermal Characteristics of Oil Film in Critical Lubrication State of Heavy Hydrostatic Bearing

Background: Lubrication failure has always been a concern in the research of heavy hydrostatic bearings. A preliminary study found that under a certain working condition, the heavy hydrostatic bearing will appear in the condition of zero local flow of oil film, which is called a critical lubrication state. It produces a significant thermal accumulation effect and affects the lubrication performance of the bearing. Objective: This paper takes Q1-205 double rectangular cavity hydrostatic thrust bearing as the research object and adopts the research method combining theoretical analysis, simulation, and experimental test to analyze the temperature rise and characteristics of the bearing when it is in critical lubrication state under different working conditions. Methods: The finite volume method is used to simulate the critical lubrication state under the condition of common load and rotating speed, and the corresponding operating parameters of the critical lubrication of heavy static support are obtained. Results: It is found that when the oil film is in the critical lubrication state, the low temperature zone is concentrated at the bearing position of the oil film, while the high temperature zone is concentrated at the counter-current side sealing edge Conclusion: The oil film's local temperature rise is intensified, and the heat accumulation phenomenon is serious because the heat cannot be taken away in time.

Triboelectric Performance of Ionic Liquid, Synthetic, and Vegetable Oil-Based Polytetrafluoroethylene (PTFE) Greases

Within electrical contacts, poor electrical conductivity of lubricants can lead to triboelectric charging, causing electrostatic currents and thermal effects, which accelerate lubrication failure. This study aimed to address these challenges by producing and testing three greases with different base oils: ionic liquid ([Oley][Oleic]), synthetic oil (PAO4), and vegetable oil-based synthetic ester (trimethylolpropane oleate). Each grease was prepared with polytetrafluoroethylene powder as the thickener. The greases were tested using a custom-made tribometer, integrated with a grounded electrical current system, with friction tests conducted with up to a 2 A electrical current flow at a constant voltage supply of 4.5 V. Under triboelectric friction testing, [Oley][Oleic] grease outperformed a commercial perfluoropolyether grease by 27.7% in friction and 16.3% in wear. This grease also showed better performance than formulated lithium grease with extreme pressure additives. The study demonstrates that greases with low interfacial resistance can retain their lubrication capacity under triboelectric conditions. These results indicate that [Oley][Oleic] grease, with its ionic liquid base oil, offers a promising solution for applications involving electrical contacts. This study highlights the potential of using advanced base oils and thickeners to enhance the performance and sustainability of lubricants in demanding environments.

Transformer-based novel framework for remaining useful life prediction of lubricant in operational rolling bearings

Accurate prediction of the remaining useful life (RUL) of lubricants in rolling bearings is crucial for maintaining efficient operation of rotating machinery and ensuring timely lubricant replacement. We propose a comprehensive framework that integrates the temporal variation transfer function (TVTF), harmonic-sideband Matrix, and the harmonic frequency transformer (HarFT), a transformer-based model. This approach effectively utilizes vibration characteristics to enhance the accuracy of lubricant degradation prediction in rolling bearings. Validation with rolling bearings experiencing lubrication failure confirms that our framework significantly outperforms alternative methods in RUL prediction. The proposed framework excels in extracting and analyzing harmonic components from vibration responses, enabling detection of minute status variations due to lubricant degradation. By applying explainable artificial intelligence (XAI), it is possible to ascertain the rationale behind the RUL predicted by the HarFT model, facilitating evidence-based decisions. Our research provides a novel strategy for lubricant RUL assessment in rolling bearings, thereby improving reliability and maintenance efficiency in industrial applications.

Enhanced Condition Monitoring of Gearboxes using Fuzzy Comprehensive Evaluation and Group Decision-making: A Case Study

In this study, we introduce a novel methodology for the condition monitoring of gearboxes by integrating fuzzy comprehensive evaluation and group decision-making. Traditional risk assessment methods often suffer from subjective biases and uncertainties inherent in expert evaluations. Our approach mitigates these limitations by aggregating expert opinions using fuzzy membership functions and assigning weights based on the similarity of individual evaluations to the group consensus. This converts qualitative judgments into quantitative measures, resulting in more precise and objective Risk Priority Numbers (RPNs). We validate the efficacy of our methodology through a case study involving a gearbox. The primary failure modes identified include gear tooth wear, misalignment, bearing failure, lubrication failure, and thermal overload. Our results indicate a significant improvement in condition monitoring accuracy, with calculated fuzzy RPN values closely aligning with historical data and expert feedback. Comparative analysis highlights the advantages of our methodology over conventional RPN calculations, particularly in reducing subjective biases and enhancing the reliability of risk assessments. Our findings demonstrate that this methodology can be effectively applied in various industrial settings, establishing a robust framework for mechanical system condition monitoring. Future research should explore integrating advanced data analytics and machine learning techniques to enhance the methodology's accuracy and efficiency.

Lubrication failure mechanism of rolling‑sliding steel ball against oil-impregnated porous polyimide and bearing steel in double friction pair

Oil-impregnated Porous Polyimide (O-PPI) cages have been widely applied in aerospace bearings because of their exceptional performance and self-lubricating characteristics, where the surface blackening failure of the O-PPI cage during the operation process significantly shortens the service lifetime. However, the blackening failure mechanisms are still not fully understood due to the complex multiple contacts between steel balls, the cage, and the inner/outer rings in the bearing system. This study aims to deeply detect the surface blackening failure mechanism of PPI materials with a relevant improvement measuring method. A double-contact rolling-sliding ball holder was developed to simulate the contact and the motion in aerospace bearings with PPI cages, where the blackening phenomenon on the O-PPI surface was replicated as the bearing ball rubbed against the PPI and steel surfaces. Comparative experiments and subsequent characterization results revealed that the iron debris generated at the ball-steel sliding interface was infiltrated into the PPI surface pores along the rolling motion of the steel ball, and then the splitting reaction of PAO oil at the steel-PPI interface catalyzed by the iron (Fe) during friction resulted in the formation of blackening products and further lubrication failure. Based on these findings, effective countermeasures are proposed to prevent similar failures in the future. This analysis is expected to enhance the operational reliability and enlarge the service lifetime of the space-bearing systems.

Synovial Lubrication Factors‐Recruiting Biomimetic Polyphenolized Hyaluronic Acid for Promoting Cartilage Repair

AbstractOsteoarthritis is a common degenerative disease characterized by continuous detachment of lubrication factors from damaged cartilage matrix. This study proposes a paradigm that combines natural polyanionic polysaccharides (hyaluronic acid, HA) with dopamine (DA) to design a synovial lubrication factors‐recruiting biomimetic polyphenolized lubrication system. The biomimetic lubricants can use DA's polarity and hydrophilic groups as specific binding sites of type II collagen's polarity and hydrophilic groups to stably bind cartilage surface, and further utilize molecular specific interaction to recruit detached, joint endogenous or chondrocytes expressed synovial lubrication factors, continuously forming supramolecular lubrication complex onto cartilage matrix to induce joint lubrication. Simultaneously, the biolubricants can also utilize catechol groups to eliminate anionic free radicals and resist reactive oxygen species invasion in the early stages of joint lubrication failure. The prepared biolubricants exhibit low coefficient of friction (µ < 0.08), which is attributed to fluid and hydration lubrication provided by HA and DA side chains through fluid dynamic effect and interfacial hydration adsorption. Cell and animal experiments also demonstrate polyphenolic biolubricants have good biocompatibility and promote cartilage regeneration. Therefore, the developed synovial lubricants‐recruiting biomimetic polyphenolized biolubricants have potential for treating osteoarthritis, and also provide a theoretical basis for other biological tissues with lubrication problems.

Numerical analysis on lubrication failure of main bearings with lemon-shaped bearing shells in high-power diesel engine

The lubrication status of crankshaft main bearings significantly affects the stability and reliability of diesel engine operation. This paper primarily investigates the severe failure of main bearings during developing an industrial high-power 6 V diesel engine and analyzes the causes of bearing failure. Main bearings using lemon-shaped bearing shells exhibited failure after a short period of operation. Based on the multi-body dynamics model, average Reynolds equation, and contact model, a lubrication model for the main bearings was established, and the lubrication characteristics of each main bearing were simulated. The research shows that the abrupt peaks of the lemon-shaped bearing shells on the first and second main bearings are located within the area where the bearings suffer from burst pressure, resulting in additional hydrodynamic pressure and asperity contact pressure on the bearing surfaces. This makes the bearing surface prone to wear and high temperature, which are the primary causes of bearing failure. Under the operating conditions, surface damage of the bearings leads to particle abrasion and high temperature. Subsequently, the lubricating oil gradually deteriorates with the combined action of high temperature and wear particles, causing the main bearings to blacken and adhesive wear.

Dramatic changes in water lubrication aroused by light

Light-controlled friction and lubrication has a wide prospect in industry and life. The friction coefficient of water lubrication between silicon nitride and titanium dioxide was found to be significantly changed by ultraviolet treatment from superlubricity to near lubrication failure. Under fully flooded conditions, the relative difference in wettability between wear and non-wear zone determined film formation of water lubrication, and its change after ultraviolet treatment aroused the failure of lubrication. While for the starved water lubrication, ultraviolet treatment slowed down the tribo-chemical reaction rate to form smaller particles on wear area, which was more conducive to lubrication and even reduced to superlubricity. Such enormous changes of water lubrication in macroscale may throw a new light on light-controlled friction and lubrication.

Rapid Failure of Lubricated Contacts with Grease Under ZEV Condition

Abstract In response to the rapid failure of grease lubrication under low surface speed with zero entraining velocity (ZEV), a common occurrence in ball screws or retainerless rolling element bearings, detailed observations were conducted through optical interferometric experiments. It was observed that despite a constant surface speed and load, the motion remained transient due to the transition between outlet cavitation and inlet starvation. The reciprocating motion of the cavitation zone rapidly depleted the contact area, leading to severe surface peeling. However, as the surface speed increased, this phenomenon was alleviated and eventually disappeared. To enhance lubrication performance, bilateral grooves were created using laser technology, proving to be advantageous for grease lubrication life under low surface speed conditions. Despite the occurrence of rapid surface failure, grease lubrication demonstrated clear benefits over oil lubrication when operating at low surface speeds.

A biomimetic lubricating nanosystem for synergistic therapy of osteoarthritis

Failure of articular cartilage lubrication and inflammation are the main causes of osteoarthritis (OA), and integrated treatment realizing joint lubrication and anti-inflammation is becoming the most effective treat model. Inspired by low friction of human synovial fluid and adhesive chemical effect of mussels, our work reports a biomimetic lubricating system that realizes long-time lubrication, photothermal responsiveness and anti-inflammation property. To build the system, a dopamine-mediated strategy is developed to controllably graft hyaluronic acid on the surface of metal organic framework. The design constructs a biomimetic core–shell structure that has good dispersity and stability in water with a high drug loading ratio of 99%. Temperature of the solution rapidly increases to 55 °C under near-infrared light, and the hard-soft lubricating system well adheres to wear surfaces, and greatly reduces frictional coefficient by 75% for more than 7200 times without failure. Cell experiments show that the nanosystem enters cells by endocytosis, and releases medication in a sustained manner. The anti-inflammatory outcomes validate that the nanosystem prevents the progression of OA by down-regulating catabolic proteases and pain-related genes and up-regulating genes that are anabolic in cartilage. The study provides a bioinspired strategy to employ metal organic framework with controlled surface and structure for friction reduction and anti-inflammation, and develops a new concept of OA synergistic therapy model for practical applications.

Diagnosis of Sliding Bearing Lubrication State Based on SC-ResNet

In response to the issue of poor diagnostic performance of models due to the scarcity of samples for lubrication failure states in sliding bearings in practical engineering applications, this thesis proposes a fault diagnosis method for the lubrication state of sliding bearings based on a Self-Calibrated Residual Network (SC-ResNet). By leveraging the self-calibrated convolution, which significantly enhances the network's receptive field and feature extraction capabilities without increasing the number of parameters and complexity, a self-calibrated residual block is designed to construct the SC-ResNet model. This model is capable of diagnosing the lubrication state of bearings using a small number of samples inputted into a pre-trained model. Experimental results indicate that this method performs exceptionally well under conditions with a limited number of samples, achieving higher Recall and F1-score values compared to other methods.

How Do Cartilage Lubrication Mechanisms Fail in Osteoarthritis? A Comprehensive Review.

Cartilage degeneration is a characteristic of osteoarthritis (OA), which is often observed in aging populations. This degeneration is due to the breakdown of articular cartilage (AC) mechanical and tribological properties primarily attributed to lubrication failure. Understanding the reasons behind these failures and identifying potential solutions could have significant economic and societal implications, ultimately enhancing quality of life. This review provides an overview of developments in the field of AC, focusing on its mechanical and tribological properties. The emphasis is on the role of lubrication in degraded AC, offering insights into its structure and function relationship. Further, it explores the fundamental connection between AC mechano-tribological properties and the advancement of its degradation and puts forth recommendations for strategies to boost its lubrication efficiency.

Hydrogels for Lubrication: Synthesis, Properties, Mechanism, and Challenges

Hydrogels have received extensive attention as functional lubricants because of their excellent anti-friction and anti-wear properties, tunable tribological performances, and effectiveness in alleviating lubrication failures caused by the creeping or leakage of conventional liquid lubricants owing to their semi-solid nature. This review summarizes the current research advances in hydrogel lubricants fabricated with various organic and/or inorganic gelators, including organic polymeric or supramolecular hydrogels, inorganic particles-based hydrogels, and organic polymer-inorganic particle hybrid hydrogels. We illustrate not only the design strategies for constructing high-performance hydrogel lubricants but also the tribological behavior and mechanism of different types of hydrogel lubricants and their potential applications in industrial and biomimetic fields. Corresponding outlooks and suggestions for future studies have also been proposed.

Tribological Behavior of Polydiethylsiloxane (PDES) in a Si3N4 and M50 System under Low Temperatures from −80 to 25 °C

Lubricants must exhibit good tribological behavior at low temperatures to ensure reliable startups in very cold regions. This study investigates the performance of lubricants, with a specific focus on their capacity for high-temperature lubrication and ensuring reliable low-temperature startup in engines. Experiments were conducted to assess the friction and wear characteristics of polydiethylsiloxane in conjunction with a Si3N4 ball and M50 (8Cr4Mo4V) steel across a temperature range of −80 °C to 25 °C. The results indicate that the coefficient of friction, as determined through friction and wear tests at various temperatures, remained below 0.1. As temperatures progressively decreased, the system’s friction coefficient increased, and wear volumes recorded at 25 °C and −60 °C were 9749.513 µm³ and 105.006 µm³, respectively, culminating in lubrication failure at −100 °C. This failure is primarily attributed to the increased viscosity and decreased mobility of polydiethylsiloxane at extremely low temperatures. Additionally, the reduced temperature increases the strength of the quenched steel, leading to hard particles or protrusions on the material’s surface, which collide with the Si3N4 ball during friction, causing adhesion and spalling. Despite this, polydiethylsiloxane forms a stable protective oil film on the surface, enhancing the system’s lubrication performance. However, below −80 °C, this oil film begins to tear, leading to diminished lubrication efficacy. This study provides valuable data supporting the field of cryogenic lubrication.

Non-Newtonian thermal elastohydrodynamic mixed lubrication in elliptical contact for nutation-driven double circular-arc spiral bevel gear pair

The new type of nutation reducer with double circular-arc bevel gears as the core is characterized by advantages such as high load-bearing capacity, large transmission ratio, and simple structure. The existing research focuses on the machining methods of gears and the analysis of tooth contact. This article first time establishes an elastohydrodynamic mixed lubrication model for nutation double circular-arc bevel gear. The model's accuracy is verified by comparing it with existing test results. On this basis, combined with the finite element method and tooth contact analysis, the meshing characteristics, tooth contact characteristics, and lubrication characteristics of the double circular-arc bevel gear tooth surface are analyzed. The results show that the entrainment velocity at the contact point of the tooth surface during transmission is much higher than the sliding velocity. Consequently, the meshing motion is close to pure rolling. In constant-speed transmission, the oil film thickness at the engaging-in and exit points near the edge of the tooth surface is smaller than that at other meshing points on the tooth surface. This phenomenon can easily lead to mixed lubrication and lubrication failure, as well as tooth surface wear. During deceleration, i.e., when the speed drops to 50 r/min, the oil film thickness approaches zero, indicating that the gear has entered a mixed lubrication state. The proposed model can be used for lubrication analysis and improving transmission accuracy of nutation double circular-arc bevel gears.