Wear Model Research Articles

A numerical study on dynamic interaction and wear of flange tip lift crossings in tramlines

Flange tip lift crossings are widely utilized in modern tramlines to replace traditional crossings to enhance commuters’ comfort and prevent crossing nose failures. However, due to altered contact conditions between wheel flanges and ramps of crossings, the use of flange tip lift crossing has led to the critical issue of ramp wear. To resolve this issue, this paper investigated the dynamic contact response of a ramp during in-service loading, as well as the resultant wear of the ramp. With a dynamic finite element model, the local contact pressure and local sliding distance were computed and subsequently applied in a local contact-based wear model to evaluate the nominal wear of the ramp. Our findings indicate that under typical in-service loading conditions, the ramp exhibited up to 120 times more wear than the rail head, owing to increased contact pressure and reduced contact area during the ramp contact. To mitigate this issue, a design change of a gentler ramp inclination from the default 1:100 ramp to a 1:150 ramp could provide approximately 10% wear reduction. In addition, increasing the flange radius by 1 mm could reduce the wear by up to 13%. Conversely, increasing the speed to 45 km/h from the recommended 15 km/h speed may cause up to 5 times more wear. Furthermore, an empty tram showed 56% less wear on the ramp when compared to the condition of the maximum allowable axle load. These results offer an insight into the detrimental wear of ramps used in flange tip lift crossings of tramlines and can assist in the development of new designs and operating guidelines to mitigate ramp wear.

A Stress-State-Dependent Sliding Wear Model for Micro-Scale Contacts

Abstract Wear is a complex phenomenon taking place as two bodies in relative motion are brought into contact with each other. There are many different types of wear, for example, sliding, fretting, surface fatigue, and combinations thereof. Wear occurs over a wide range of scales, and it largely depends on the mechanical properties of the material. For instance, at the micro-scale, sliding wear is the result of material detachment that occurs due to fracture. An accurate numerical simulation of sliding wear requires a robust and efficient solver, based on a realistic fracture mechanics model that can handle large deformations. In the present work, a fully coupled thermo-mechanical and meshfree approach, based on the momentum-consistent smoothed particle Galerkin (MC-SPG) method, is adapted and employed to predict wear of colliding asperities. The MC-SPG-based approach is used to study how plastic deformation, thermal response, and wear are influenced by the variation of the vertical overlap between colliding spherical asperities. The findings demonstrate a critical overlap value where the wear mechanism transitions from plastic deformation to brittle fracture. In addition, the results reveal a linear relationship between the average temperature and the increasing overlap size, up until the critical overlap value. Beyond this critical point, the average temperature reaches a steady-state value.

Atomic-scale wear behaviors of iron oxide through the atom-by-atom attrition and plastic deformation of nano-asperities

Atomic-scale wear, behaving distinctly from macroscale wear, has been gaining significant scientific interest. We previously proposed a semi-empirical wear model for covalent bonding materials, which primarily describes an interfacial-bond-dominant atomic-scale wear process. To assess the model's broader applicability on other material types, herein we selected the iron oxide (Fe2O3) as a representative ionic bonding material and conducted the large-scale atomistic simulations. The simulations unveiled two main atomic-scale wear mechanisms of Fe2O3: plastic deformation/cracking of nano-asperities induced by the asperity collision, and atom-by-atom attrition caused by the interfacial O–Fe bond formation. Crucially, our simulations proved effective in capturing the atom-by-atom attrition wear, thus confirming its validity for ionic materials and expanding its potential usefulness to a broader range of materials.

Tire Wear and Pollutants: An Overview of Research

Tire Road and Wear Particles are a major source of microplastic emissions. Tire and Road Wear Particles are important to study and understand as there are alarming amounts found in various environments. Currently, Tire and Road Wear Particles compared to other microplastics are not studied as rigorously in literature but are becoming a larger field of study due to their impact on emissions control. Tire Road and Wear Particles are commonly found as Styrene Butadiene Rubber Butadiene Rubber, and Natural Rubber To understand and quantify tire wear, experimental and mathematical models are developed to estimate tire wear. Tire wear can be measured experimentally using semi-empirical models, predetermined data, and sensor technologies. Tire wear is also measured mathematically using different modeling approaches and different friction models. This review discusses different and popular methodologies for estimating tire wear through experimental and simulated environments. Furthermore, discusses a review of the literature regarding tire wear emissions and its impact on the environment. Finally, it is evident that an accurate simulated tire wear model can be developed in the future alongside a driver model to predict tire wear emissions.

Influences of tram characteristics on wheel polygonal wear evolution

Out-of-round railway wheels continuously excite the vehicle-track system resulting in fluctuating contact forces, creepages and contact patch dimensions. Accompanied wear may influence the evolution of railway wheel polygonization significantly. Especially in curves with a small radius of curvature, which are typical for tramway networks, considerable wear originates due to high lateral creepages. Long-time wear development studies with dominant polygonal orders reveal that some wavelengths of the wheel enlarge rapidly, whereas others are nearly unaffected or even suppressed. Therefore, fundamental research on significant influences on wheel polygonal wear evolution is required. A representative generic system model of a two-axle tram bogie is set up, and a suitable wear model is implemented to study the polygonal wear evolution at trams. It has been found that structural modes can dominate wheel polygonal wear evolution. In particular, the compliance and interaction of the wheelset axle and the resilient wheel may be essential. Evolution tendency curves are presented, and influences on the wheel polygonization are discussed. Wheel–rail contact conditions and related creepage–creep force characteristics appear to be decisive for the evolution directions and evolution speeds.

A study on building and testing fractal model for predicting end face wear of Aeroengine's floating ring seal

The graphite floating ring is a key sealing element of the turbopump of aeroengines. Its wear induced by frequent flotation during its operation can result in stress concentration and microscopic cracks in its seal end face, more leakage from its sealing surface, a lower engine efficiency, and even serious safety concerns. However, there are currently no published studies regarding the modeling of the end face wear of the floating ring seal. This work presents a new fractal model for predicting the wear rate and wear evolution of the end face of the floating ring seal. Firstly, a new normal fractal contact model was implemented by microscopically considering the deformation mechanism, interaction forces, and flash points of the asperities on the end face of the floating ring. On this basis, a fractal model was built to predict the wear of the end face of the floating ring according to its wear mechanism and the corrected Archard theory. The wear rates predicted according to this model are in good agreement with the test results. The simulation results show that (i) the depth wear rate of the end face of the floating ring first decreases and then increases as the fractal dimension D increases (the minimum is reached when the fractal dimension ranges from 1.60 to 1.725); (ii) the depth wear rate of the end face of the floating ring increases as the characteristic scale G, friction factor f, floatation speed of the floating ring v, and end face pressure P increase; (iii) the impact of the end face pressure on the depth wear rate is minimum when the fractal dimension ranges from 1.60 to 1.65; (iv) the flotation displacement of the floating ring cannot exceed 12 μm when the engine speed is higher than 30,000 r/min.

Study on dynamic wear law of PDC bit under temperature effect

Accurate prediction of the PDC bit wear trend and life is of great significance for improving oil and gas drilling efficiency and reducing oil and gas production costs. However, due to the combination of high temperature and load, the interaction between cutter wear, force, and body temperature changes dynamically in real-time, making it a challenge to accurately predict the life of bit cutters. This paper aims to explore the dynamic wear law of the PDC bit under temperature effect. Firstly, the PDC cutter wear experiment under the temperature effect is studied, and the microstructure and phase changes after exposure to high temperature are characterized. Then, the PDC cutter mathematic models of volume wear, line wear, cutting force, and cutter temperature rise are constructed. Finally, the dynamic wear law of the PDC bit is studied by numerical simulation. The results show that when the rake angle is 12.86°, it has better wear resistance and longer drilling footage. Increasing the footage per turn of the PDC bit aids in lowering the wear degree within the permitted range of weight-on-bit (WOB). With each increase in drillable grade, the depth of drilling achieved by PDC bits at the same wear height decreases by more than 50%. The final wear height of the PDC bit cutter considering the temperature effect is about twice that without considering the thermal effect. The numerical calculation method proposed in this paper can calculate parameters such as dynamic force change, dynamic temperature change and dynamic wear height of PDC bit during drilling, and has the advantages of fast calculation speed and diversified analysis types. The research results provide a theoretical basis and support for the life prediction of worn PDC bits.

Prediction and optimisation for surface roughness distribution in external spline shaping based on micro-element method

Previous surface topography prediction models for external spline shaping do not consider the relationship between the tool and workpiece geometry and cutter edge wear. In this work, by considering the tool–workpiece geometry correlation, a model for the tooth surface topography of the external spline is established based on the micro-element method. Combined with adhere model, a gear shaper wear model is founded on the wear mechanism of cutter edge micro-element derived from the abrasive wear mechanism. The distribution characteristics of tooth topography are analysed through an external spline shaping experiment, which verifies the validity of the presented model. For the uneven distribution of tooth surface topography, a shaping process optimisation algorithm is proposed based on the advance-and-retreat method, which can obtain tooth surfaces with uniform surface topography distribution and reduce tool wear. This work can guide the optimisation of the external spline shaping process, improve the integrity of the tooth surface and prolong the serviceable life of gear shaper.

Atomic-scale insights into the tribochemical wear of diamond on quartz surfaces

A detailed understanding of diamond wear is crucial due to its use in high-performance cutting tools. Despite being a much harder material, diamond shows appreciable wear when cutting silicon dioxides due to a tribochemical mechanism. Here, we use nonequilibrium molecular dynamics simulations with a reactive force field to investigate the wear of single-crystal diamond tips sliding on α-quartz surfaces. Atom-by-atom attrition of carbon atoms is initiated by the formation of C-O interfacial bonds, followed by C-C cleavage, and either diffusion into the substrate or further oxidation to form CO2 molecules. Water molecules dissociate to form hydroxyl groups, which passivates the surfaces and reduces interfacial bonding and wear. At low loads, the initial wear rate increases exponentially with temperature and normal stress, consistent with stress-augmented thermally activated wear models. At higher loads, the initial wear rate becomes less sensitive to the normal stress, eventually plateauing towards a constant value. This behaviour can be described using the multibond wear model. After long sliding distances, wear also occurs through cluster detachment via tail fracture. Here, wear becomes approximately proportional to the sliding distance and normal load, consistent with the Archard model. The normalised wear rates from the simulations are within the experimentally-measured range.

Numerical analysis and formula correction of mechanical seal ring wear of slurry pump based on thermal deformation

In view of the excessive wear of the mechanical seal of the slurry pump in the project and the inconsistency between the theoretical wear and the actual wear, this article studies the wear of the mechanical seal of the slurry pump. In this article, a numerical model of mechanical seal wear based on thermal deformation is established. The hardness, wear coefficient and dry friction coefficient of the sealing ring were obtained through experiments, and the wear morphology was collected by the ultra-depth microscope. In this article, the precise calculation of mechanical seal wear is realized, and the seal ring wear depth under single and multiple field conditions is obtained. The wear formula of the mechanical seal is optimized by adding a correction index, and the end face structure of the mechanical seal is improved. The results show that: the seal ring forms a converging surface due to thermal deformation resulting in more severe wear of the inner diameter relative to the outer diameter; the revised wear equation can more accurately predict the life of the nickel-based tungsten carbide alloy mechanical seal, with a 3.2 times increase in expected life after comprehensive end face improvement.

Analysis of the tribological behavior of the high-speed and heavy-load braking interface with dynamic wear of brake pads

Using a megawatt wind turbine disc brake as a case study, this work analyzes the effects and action mechanism of dynamic wear on the braking interface of the braking pad on tribological behaviors as contact state, temperature field, and pressure distribution. The Archard wear model was incorporated into the solution of the tribological problem of the braking interface in ABAQUS using the arbitrary Lagrangian–Eulerian (ALE) technique through the UMESHMOTION subroutine. The wear interface meshes were changed without modifying other finite element analysis variables. Moreover, wear testing on the inertia braking tester validated the coupled heat-stress-wear model of the brake pad. The differences in the tribological behaviors of the braking interface with and without the dynamic wear of the braking pad were analyzed based on the simulation results of friction and wear in a braking cycle. The study revealed that the tribological behaviors of the braking interface were significantly affected by the dynamic wear of the braking pad. Specifically, the wear evolution changed the contact state, the area of stress concentration, and the temperature field distribution during the braking process. Hence, the wear properties of the brake pad were modified as a result of these tribological behaviors.

Investigation on Tooth Surface Wear of Cycloid Drives Considering Tooth Profile Modifications

Cycloid drives are widely used in various mechanical systems due to their high reduction ratio, compact size, and high efficiency. Tooth surface wear is a major problem that affects the reliability and durability of cycloid drives. However, compared to the research on the wear of involute gears, the prediction of tooth surface wear in cycloid drives is relatively limited and less extensive. To fill this gap, the theoretical wear model of the tooth surface of cycloid-pin gear pairs is proposed based on the Hertz contact theory and Archard’s formula, with consideration of tooth profile modifications. Firstly, the loaded tooth contact analysis model is established to determine the relative sliding velocity and tooth contact stress. Secondly, the calculation steps of single tooth surface wear are presented within one gear mesh cycle. With this, the effects of the tooth profile modifications, the operating conditions such as output torque, input speed, and the assembly eccentricity on the wear depth within one gear mesh cycle are investigated. This study gives a deeper understanding of the tooth surface wear mechanisms of cycloid drives and could be employed to assist gear design and to improve the wear resistance.

Fatigue crack growth in wheel-rail rolling-sliding contact: A perspective of elastic-plastic fracture mechanics criterion

The presence of fatigue crack is a common damage pattern in railway wheel-rail system, which will reduce service life and increase the maintenance costs of railway transportation. In this study, a two-stage simulation strategy was proposed to investigate the elastic-plastic fatigue crack growth behaviour of the wheel and rail, where a three-dimensional wheel-rail rolling contact finite element model was first built to solve the elastic-plastic wheel-rail contact pressure and tangential traction modification, and then a simplified three-dimensional finite element model of the wheel and rail inserted with vertical cracks under the equivalent moving load was built to explore the fatigue crack growth. Taking the J-integral at the crack tip as an elastic-plastic crack growth parameter, the influences of crack face friction, crack depth and traction coefficient on the crack growth were elucidated. Meanwhile, the competing mechanisms of wheel/rail wear and fatigue crack growth under rolling-sliding contact condition was illuminated based on the Archard wear model. The simulation results indicate that two critical locations for crack growth appear during the contact load approaching and departing from the crack. The Mises stress near the deepest crack tip exceeds the yield stress, causing a small plastic zone with the greatest crack growth rate. The reduction in the crack face friction, and/or the increase in crack depth and traction coefficient will accelerate the propagation of fatigue crack. In the case of only normal contact load or rolling-sliding contact (μ ≤ 0.375), the crack growth on the wheel and rail is dominant compared to wear and crack will continue to grow.

Wear rate and profile prediction of Cu-impregnated carbon strip for high-speed pantograph

The wear status of pantograph carbon strips has a crucial impact on the receiving quality of high-speed trains, and accurate wear rate prediction is essential for timely maintenance and replacement. In this study, the wear mechanism of Cu-impregnated carbon strip is analyzed through micro-analysis, and an improved method for calculating wear rate is proposed by enhancing the original Holm-Archard adhesive wear model. The proposed approach considers the collecting current of the pantograph, burning arc, and contact loss rate of the pantograph, thereby improving the accuracy of wear rate calculation. Moreover, the study validates the relationship between contact resistance and contact force by comparing the model's results with experimental data. Furthermore, the wear profile of MCS is predicted and calculated by considering the wear position of the zigzag catenary on the sliding plate, which provides a more comprehensive analysis of the wear behavior of MCS. To validate the proposed model, actual wear and operation data of an eight-unit high-speed train's pantograph are employed, and the results indicate an average absolute error of 0.19 mm at the deepest wear depth (−16 mm–16 mm) of MCS, which demonstrates the feasibility and effectiveness of the proposed model.

Dynamics and Wear Prediction of Mechanisms Considering Multiple Clearances and Coatings

The increase in joint clearance and system vibration caused by joint wear are important factors that may lead to the failure of the mechanism and a decrease in the motion accuracy of the actuator. In this paper, to investigate the impact of different numbers of spherical joint clearances on the dynamics performance of the mechanism and explore effective measures to reduce the vibration of the mechanism caused by multiple joint clearances, on the basis of the previous research on the mechanism dynamics when there is clearance in a single spherical joint, an improved contact force model is used to study the effects of coating, no coating, and different clearance quantities on the dynamics of a mechanism containing multiple spherical joint clearances. Moreover, the joint reaction forces and contact-impact forces under different working conditions are calculated. In order to reduce the difficulty of calculating the joint wear, an approximate calculation method for contact area is proposed, and an improved Archard wear model is employed to calculate and analyze the changes in wear amount under the influence of both spherical joint clearance and coating.

Numerical Simulation of Conveying Fine Powders in a Screw Conveyor Using the Discrete Element Method

Due to their high efficiency and spatial utilization, screw conveyors are widely used in pharmacy, agriculture, and industry. Recently, this has made it a popular research subject in the numerical modelling of the transport of bulk solids. Modelling of granular systems at the level of individual particles is mainly possible due to the use of discrete numerical methods. The most common is the use of the Discrete Element Method (DEM), which is still limited from the point of view of simulations on an industrial scale, as increasing the size of the system also increases the cost of simulation. Certain powders with low density, large angles of repose, poor fluidity, and bad flowability can accumulate during transportation, causing inaccurate and non-uniform movement. Additionally, the friction and impact between the particles can cause wear. To address these issues, the present study utilizes the discrete element method to simulate and analyse powder transportation in an inclined screw conveyor using the commercial software ANSYS-ROCKY. Numerous phenomena that arise while transporting and feeding small-sized or irregularly shaped particles, often present in industrial processes, remain insufficiently investigated. This paper aims to analyse the transportation process of adhesive powders in a screw conveyor, with a focus on evaluating the impact of different screw blade speeds on transport. Multiple simulations were conducted, along with the implementation of an additional wear model, to better understand the transport phenomena and wear. An example was used to demonstrate the impact of screw speed on the wear of the transporter due to the interaction between the material and the structure of the conveyor, power consumption, and performance.

Numerical Simulation and Experimental Study on Sediment Wear of Fixed Guide Vanes of Hydraulic Turbines in Muddy River Based on Discrete Phase Model

The erosion of the fixed guide vane of a hydraulic turbine by sandy water is influenced not only by flow velocity and mud concentration but also by the direction and speed of the sandy water over the surface. This study aims to investigate the erosive effect of sediment-laden water on a specific type of hydraulic turbine’s fixed guide vane, validate the efficacy of the discrete phase model (DPM) in simulating wear on the fixed guide vane, and identify the critical areas of wear on its surface. To achieve these objectives, the wear model and DPM model are employed to conduct numerical simulations on the fixed guide vane. Additionally, samples of sand are collected from the power station site, and laboratory tests are conducted on the hydraulic turbine’s flow passage components using actual sediment concentration and sand-to-water ratio to determine the sediment wear conditions. The numerical simulation results of the guide vane’s surface wear rate are compared with the experimental data to verify the wear condition of the fixed guide vane under its rated working condition. These findings serve as a reference for the later-stage design of erosion-resistant solid guide vanes for hydraulic turbines.

Transient tribo-dynamic performance of journal bearings considering wear behavior during start-up

The transient tribo-dynamics and wear model are coupled to study the mixed lubrication-wear behavior during start-up. The coupled numerical model involves the film thickness equation with wear depth and a time-varying wear coefficient to account for the impact of transient mixed lubrication behavior on wear. In this study, the evolution of wear and mixed lubrication performance distribution over time is predicted, and the impact of acceleration mode, acceleration time, external load, lubricant viscosity, and start-up time on the numerical predictions is evaluated. The findings demonstrate that wear behavior, particularly in the analysis of the effects of acceleration mode and acceleration time, has a significant impact on the evaluation of the bearing-rotor system's start-up performance and even changes the determination of optimal parameters. Furthermore, the parametric study demonstrates that wear and mixed lubrication performance are sensitive to the external load and lubricant viscosity. Finally, studies on the effect of start-up times show that proper wear geometry promotes hydrodynamic effects, but severely worn bearing surfaces have a negative effect on start-up.

Establishment of high-temperature fretting wear prediction model for metal rubber with complex helical network structure

In this study, a high-temperature fretting wear prediction model was established for metal rubber, which was then validated through experiments. Initially, a three-dimensional numerical model of metal rubber was reconstructed, and statistical distribution of contact points and types of curved wires inside the virtual component was achieved. Meanwhile, a high-temperature fretting wear evolution model for curved wires was constructed by introducing a temperature function f(T), considering material thermal expansion, softening, and oxidation. Subsequently, the model was incorporated into the macro model, establishing a cross-scale predictive model for wear from micro-coil elements to component wear. Experimental validation demonstrated good prediction performance of the model, with a maximum wear mass prediction error of 14.81% and prediction errors below 10% for 80,000 cycles.

Erosion analysis of radial flow hydraulic turbine components through FLUENT-EDEM coupling

The hydraulic turbine performance is adversely affected by sediment erosion. The present study aims to explore the erosion behavior of radial hydraulic turbine. Numerous shapes, sizes, and concentrations of sediment particles striking the turbine were analyzed numerically and experimentally. Numerical analysis was performed in ANSYS-FLUENT and EDEM coupled system based on the Archard wear model, which is new for particle dynamics simulation within turbine. Experiments were performed by injecting various-sized particles into a transparent-casing turbine. The experimental analysis traced erosion in the blade's suction and leading side. The overall experimental uncertainty was 0.53%. Numerical analysis indicates that erosion occurs at the casing (62%), the blade's suction side (10.2%), and the leading side (12.9%). Finally, applying the genetic algorithm relationship between the normalized erosion rate density with the particle's velocity, size, concentration, and shape factor was established. Erosion loss increased with increased particle concentration and size and decreased shape factor.