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This paper investigates the effect of nitrogen content on the tribological behavior of 316L (N) stainless steel at three different nitrogen levels: 0.07, 0.11 and 0.22 wt. percent. AISI 316L (N), an austenitic stainless steel, is the primary structural material used in sodium-cooled prototype fast breeder reactors (PFBR). Wear tests were conducted using a pin-on-disc tribometer, with a sliding velocity of 0.8 m/s and a normal load of 40 N, over a sliding distance of 1000 m. The experiments were carried out against an Inconel 718 counter face material at four different temperatures: room temperature, 200 °C, 400 °C and 550 °C. The dry sliding wear tests were performed in a vacuum of 10–6 torr to simulate wear in liquid sodium. The investigation covered the properties of the three grades of stainless steel, including microstructure, hardness, X-ray diffraction (XRD), specific wear rate, wear resistance and wear coefficient. This study also compared three different wear models a weight loss model, an ASTM model, and geometric models highlighting the reported anomalies. Scanning electron microscope (SEM) photographs of the worn surfaces were used to assess the severity and mode of wear. It was discovered that wear resistance decreases as temperature increases due to the material's thermal softening, and that the stainless steel with 0.07 wt% nitrogen exhibited the best wear resistance among the tested compositions. [ABSTRACT FROM AUTHOR]

The wear of small-caliber barrels is one of the key factors affecting barrel life. Based on the Archard wear model, a high-temperature pin plate wear experiment was carried out, and wear models of chrome-plated layers and gun barrel materials were established. In addition, a finite element model of the interaction between the bullet and the barrel was established. The movement of the projectile along the barrel was simulated and analyzed, and the force distribution of the spatial geometry structure of the rifling was mastered through simulation. The wear law of the gun barrel along the axial direction was obtained based on the wear model of the chrome-plated layer and gun barrel material. A position 100 mm away from the barrel breech wears very fast; this position is where the cone of the bullet is engraved in the barrel. At the position 150–350 mm away from the barrel breech, the barrel bore wears even faster. The barrel chrome layer is mainly affected by the gunpowder impact and projectile engraving, which is consistent with the actual failure of the coating. When the distance to the barrel breech is 350 m, the wear becomes stable. Through an analysis of the diameter of the barrel, it was found that, when the diameter of the barrel exceeded 12.85 mm, the barrel reached the end of its life. [ABSTRACT FROM AUTHOR]

Abstract To ensure an accurate selection of rolling guide shoe materials, an analysis of the intricate relationship between linear speed and wear is imperative. Finite element simulations and experimental measurements are employed to evaluate four distinct types of materials: polyurethane, rubber, polytetrafluoroethylene (PTFE), and nylon. The speed-index of each material is measured, serving as a preparation for subsequent analysis. Furthermore, the velocity-wear factor is determined, providing insights into the resilience and durability of the material across varying speeds. Additionally, a wear model tailored specifically for viscoelastic bodies is explored, which is pivotal in understanding the wear mechanisms within the material. Leveraging this model, wear predictions are made under higher speed conditions, facilitating the choice of material for rolling guide shoes. To validate the accuracy of the model, the predicted degree of wear is compared with experimental data, ensuring its alignment with both theoretical principles and real-world performance. This comprehensive analysis has verified the effectiveness of the model in the selection of materials under high-speed conditions, thereby offering confidence in its reliability and ensuring optimal performance.

Objective Based on the measured data of the train wheelsets on Shanghai Metro Line 17, the wheelset wear pattern is studied, and a wear model of wheel rim thickness and wheel diameter is established to improve the safety and maintenance efficiency of urban rail transit vehicles. Method The measured wheelset data are pre-processed to eliminate data errors. Curve fitting and error analysis method are used to establish the wear model of wheel rim thickness and wheel diameter. The fitting standard deviation of wear rate and that of the error value between the true value and the error fitting curve are used as evaluation indexes to evaluate the accuracy of the wear model. The wheelset wear model is verified with Train 1701 and Train 1721 respectively. Result & Conclusion Both the fitting standard deviation of 4th power fitting curve of wear rate for Train 1701 and Train 1721 wheelset rim thickness and wheel diameter, and that of 6th power fitting curve of the error value between the true value and the error fitting curve are close to zero, verifying that the vehicle wheelset wear model can accurately predict the wheelset wear of different types of trains and different vehicle positions of the same train on Shanghai Metro Line 17.

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a crucial part in micro-electromechanical manufacture, local ultra-precision processing of highly ductile copper is expected to be realized by fluid jet polishing (FJP), which widely utilized in optical elements. Since copper exhibits different wear behavior from stiff and brittle material, there is currently no abrasive wear prediction model applicable for copper to investigate the polishing mechanism. This research reveals that the copper material removal is dominated by deformation wear rather than cutting wear through abrasive jet impact experiments and localized wear scars analysis. A three-dimensional gas-liquid-particle triphasic wear model for copper in FJP is developed by considering impact energy and wear mechanism simultaneously. Ultimately, validation assessments at various working pressures and impingement angles achieve the goodness-of-fit up to 0.92–0.97 in quantitative comparison between simulations and experimental measurements, which demonstrate the wear prediction ability of the proposed model. This investigation facilitates a better understanding of copper wear mechanism and provides theoretical guidance for FJP process optimization. [ABSTRACT FROM AUTHOR]

To ensure an accurate selection of rolling guide shoe materials, an analysis of the intricate relationship between linear speed and wear is imperative. Finite element simulations and experimental measurements are employed to evaluate four distinct types of materials: polyurethane, rubber, polytetrafluoroethylene (PTFE), and nylon. The speed-index of each material is measured, serving as a preparation for subsequent analysis. Furthermore, the velocity-wear factor is determined, providing insights into the resilience and durability of the material across varying speeds. Additionally, a wear model tailored specifically for viscoelastic bodies is explored, which is pivotal in understanding the wear mechanisms within the material. Leveraging this model, wear predictions are made under higher speed conditions, facilitating the choice of material for rolling guide shoes. To validate the accuracy of the model, the predicted degree of wear is compared with experimental data, ensuring its alignment with both theoretical principles and real-world performance. This comprehensive analysis has verified the effectiveness of the model in the selection of materials under high-speed conditions, thereby offering confidence in its reliability and ensuring optimal performance. [ABSTRACT FROM AUTHOR]

The use of mining pumps to transport solid-liquid two-phase flows results in solid particles causing varying degrees of wear in the flow-passing components of the pump. In this study, a computational fluid dynamics analysis was performed employing SST k-ω turbulence and discrete phase models to predict the wear characteristics of small two-stage mining pumps. The wear rates of the flow-passing components (first- and second-stage impellers and guide vanes) of the pump were simulated considering three solid-particle sizes under three flow conditions (low flow, rated flow, and high flow), with the highest wear rate occurring on the surfaces of the first-stage guide vane in the low-flow condition. Subsequently, a pump wear experiment was performed using an experimental pump with parameters and structure similar to the numerical model at the pump's rated flow. The experimental results were compared to numerical results obtained using the same numerical method and wear model. The wear characteristics shown in the numerical and experimental results were consistent with each other. Thus, the numerical method used in this study can accurately predict the wear of flow-passing components in a mining pump, and the method was found to be suitable for the prediction of wear characteristics in mining pumps. [ABSTRACT FROM AUTHOR]

Copyright of Urban Mass Transit is the property of Urban Mass Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Feldspar ceramic materials are widely used as dental ceramic materials in the field of dental prosthetics. Studying their wear mechanisms is of great significance for the evaluation and prediction of dental ceramic life. This paper studies the wear mechanisms of feldspar ceramic materials from the aspects of wear performance experiments and finite element analysis. The high speed ring block friction and wear tester were used to conduct 3.5 x 105 times wear tests on the Sirona CEREC Blocks feldspathic ceramic block under the load of 10, 20, 30 N and 40 N. The changes of wear quality, wear rate, etc. with respect to load and wear times were obtained. According to the change curve, the wear process of feldspathic ceramics was divided into three stages and the wear surface morphology of each stage was observed. The Archard wear model was modified and improved, and based on this, the finite element simulation research was carried out through the UMESHMOTION subroutine in ABAQUS. Two node paths were selected to conduct simulation analysis on the adaptive mesh area of ALE for wear under four load sizes and 3.Ox 105 wear cycles. Compared with the experimental wear depths, the maximum error under 10N load was 12.18%, and the minimum error under 30 N load was 8.64%. [ABSTRACT FROM AUTHOR]

The wear profile analysis, obtained by different tribometers, is essential to characterise the wear mechanisms. However, most of the available methods did not take the stress distribution over the wear profile in consideration, which causes inaccurate analysis. In this study, the wear profile of polymer–metal contact, obtained by block-on-ring configuration under dry sliding conditions, was analysed using finite element modelling (FEM) and experimental investigation. Archard's wear equation was integrated into a developed FORTRAN–UMESHMOTION code linked with Abaqus software. A varying wear coefficient (k) values covering both running-in and steady state regions, and a range of applied loads involving both mild and severe wear regions were measured and implemented in the FEM. The FEM was in good agreement with the experiments. The model reproduced the stress distribution profiles under variable testing conditions, while their values were affected by the sliding direction and maximum wear depth (hmax). The largest area of the wear profile, exposed to the average contact stresses, is defined as the normal zone. Whereas the critical zones were characterized by high stress concentrations reaching up to 10 times of that at the normal zone. The wear profile was mapped to identify the critical zone where the stress concentration is the key point in this definition. The surface features were examined in different regions using scanning electron microscope (SEM). Ultimately, SEM analysis showed severer damage features in the critical zone than that in the normal zone as proven by FEM. However, the literature data presented and considered the wear features the same at any point of the wear profile. In this study, the normal zone was determined at a stress value of about 0.5 MPa, whereas the critical zone was at about 5.5 MPa. The wear behaviour of these two zones showed totally different features from one another. [ABSTRACT FROM AUTHOR]

Abstract The wear profile analysis, obtained by different tribometers, is essential to characterise the wear mechanisms. However, most of the available methods did not take the stress distribution over the wear profile in consideration, which causes inaccurate analysis. In this study, the wear profile of polymer–metal contact, obtained by block-on-ring configuration under dry sliding conditions, was analysed using finite element modelling (FEM) and experimental investigation. Archard’s wear equation was integrated into a developed FORTRAN–UMESHMOTION code linked with Abaqus software. A varying wear coefficient (k) values covering both running-in and steady state regions, and a range of applied loads involving both mild and severe wear regions were measured and implemented in the FEM. The FEM was in good agreement with the experiments. The model reproduced the stress distribution profiles under variable testing conditions, while their values were affected by the sliding direction and maximum wear depth (h max). The largest area of the wear profile, exposed to the average contact stresses, is defined as the normal zone. Whereas the critical zones were characterized by high stress concentrations reaching up to 10 times of that at the normal zone. The wear profile was mapped to identify the critical zone where the stress concentration is the key point in this definition. The surface features were examined in different regions using scanning electron microscope (SEM). Ultimately, SEM analysis showed severer damage features in the critical zone than that in the normal zone as proven by FEM. However, the literature data presented and considered the wear features the same at any point of the wear profile. In this study, the normal zone was determined at a stress value of about 0.5 MPa, whereas the critical zone was at about 5.5 MPa. The wear behaviour of these two zones showed totally different features from one another.

As the application of nickel-based heat-resistant alloy, a difficult-to-cut material, increases in aerospace engine, gas turbine and automotive parts, tool wear is emerging as an important issue. In this paper, finite-element (FE) simulations and experimental approaches are presented to estimate the tool wear of coated tungsten carbide cutting tools in the orthogonal cutting of Inconel 718. A tool wear model depends strongly on the experimentally acquired wear rates, which are measured by cutting tests. A three-dimensional data-based measurement method was investigated, and the volume loss of the tools was obtained to measure the wear geometries accurately. FE simulations of the cutting process were performed to calibrate the tool wear model by predicting the tool–workpiece interface temperature and normal stress. The constants of the tool wear model, for which the temperature-dependent wear model and Usui's wear model were applied, were determined by a hybrid approach using FE simulation and experimental results. The approach was validated by comparing the estimated values with the experimental data. [ABSTRACT FROM AUTHOR]

This study introduces the active learning strategy and Kriging model into the reliability assessment of spur gear wear. First, the wear model of spur gears is constructed based on Archard's model, and its wear life is approximately estimated. Next, the uncertainty factors affecting the wear life are analyzed and quantified, which causes the reliability problem of spur gear wear. Then, the active learning Kriging model is introduced to estimate the wear reliability for highly efficient and highly accurate computation. Finally, the result analysis for a spur gear is provided, and the relevant results reveal the evolutionary law of spur gear wear depth with working pressure angle. Meanwhile, the wear reliability of spur gears is estimated by different learning functions for comparative analysis, and it is eventually estimated as approximately 99.45 %, which guides decision makers in engineering practice. In addition, Monte Carlo simulation is adopted to validate the accuracy of the estimated wear reliability of spur gears. [ABSTRACT FROM AUTHOR]

The use of mining pumps to transport solid-liquid two-phase flows results in solid particles causing varying degrees of wear in the flow-passing components of the pump. In this study, a computational fluid dynamics analysis was performed employing SST k-ω turbulence and discrete phase models to predict the wear characteristics of small two-stage mining pumps. The wear rates of the flow-passing components (first- and second-stage impellers and guide vanes) of the pump were simulated considering three solid-particle sizes under three flow conditions (low flow, rated flow, and high flow), with the highest wear rate occurring on the surfaces of the first-stage guide vane in the low-flow condition. Subsequently, a pump wear experiment was performed using an experimental pump with parameters and structure similar to the numerical model at the pump’s rated flow. The experimental results were compared to numerical results obtained using the same numerical method and wear model. The wear characteristics shown in the numerical and experimental results were consistent with each other. Thus, the numerical method used in this study can accurately predict the wear of flow-passing components in a mining pump, and the method was found to be suitable for the prediction of wear characteristics in mining pumps.

Rutting is the most common and most dangerous defect of asphalt pavements. One of the problems of northern countries such as the Russian Federation is abrasive rut due to studded tire loading. Precise prediction of the asphalt concrete abrasion and wear resistance allows improving the durability and reliability of asphalt pavements. Several laboratory tests are used for the prediction of asphalt concrete abrasion resistance. An abrasive wear model of asphalt concrete is needed to predict wear resistance changes under different conditions. The aim of this article is to evaluate compaction quality effect and air voids value on the abrasion resistance of asphalt concrete. To estimate the influence of the percentage of connected voids on abrasive wear of asphalt concrete, an asphalt wear model was presented. This model is based on G.Y. Lee’s approach. This approach divides the abrasive processes into normal abrasion and particle loss. Air voids lead to the aggregate loss and affect the abrasion resistance of the asphalt pavements. Calculation of these effects is possible using G.Y. Lee’s approach. Calculations of the lost particles include the empirical coefficient (1/mm) characterizing the influence of the pores on the lack of adhesion to the aggregate particle surface and the influence of the lack of adhesion on the fraction of lost particles. The Prall test was used for the abrasion resistance estimation. The saturation degree method was used for the estimation of compaction quality and air voids content. For the coefficient estimation, 63 samples of different mixes were tested. The mixes were used for the construction of the Republic of Tatarstan road network. The used asphalt concretes correspond to requirements of Russian standards GOST 9128-2013 and GOST 31015-2002. The experiments show good reliability of the presented model. This model predicts abrasion resistance of asphalt concretes under uncompaction and provides insight into the abrasive wear processes in the asphalt concretes. Furthermore, the study results allow us to improve the laboratory tests precision by 2.3 % by excluding the uncompaction effect during the comparison of the results.

In the long-distance pigging operation of natural gas pipelines, severe wear of the sealing cups always leads to the failure and instability of the pig. Different from ordinary conditions, the wear process of the polyurethane rubber (PUR) used in the pigging operation occurs under the condition of interference fit, which generates a continuously varied wear rate. In this research, a custom-built wear experiment was designed and conducted by adopting a specially made indenter and specimen, and then the effect of contact pressure on the wear rate, i.e., the empirical expression of wear rate, was obtained based on the test results and Hertz contact theory. In addition, a numerical model that presents the PUR interference wear behaviors was established by combining the empirical expression of the wear rate and the analytical expression of the hyperelastic materials under the interference fitting. Through MATLAB programming with the iterative algorithm, the wear laws of two kinds of sealing cups were investigated, and the results indicate a coupling induction among the wear rate, wear loss, and contact pressure. The variation of wear loss with traveling distance was proven to agree with the exponential function, and thus a prediction model suitable for engineering practice was built to calculate the wear loss of the sealing cups. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. [ABSTRACT FROM AUTHOR]

As rack-and-pinion is the key driving part of rack railway， mastering the wear condition and law of the gear rack pair tooth surface during the operation of the gear rail vehicle is conducive to ensuring the smooth and safe operation of the gear rail vehicle. For this purpose， the process of variable mounting distance transmission of rack-and-pinion in the form of Strub rack railway is analyzed， and the key parameters of variable mounting distance transmission are calculated accordingly； by introducing the mounting distance step and slip distance step， the continuous transmission process of rack and pinion pair with variable mounting distance is discretized， and the mathematical model of wear volume and wear depth of tooth surface of variable installation distance rack-and-pinion is constructed； in order to verify the accuracy of the mathematical model， rack wear test is carried out； combined with concrete examples， the influence of different parameters on tooth surface wear is analyzed to obtain the key factors affecting the wear of tooth surface and their influencing rules. The results show that the measured value of tooth surface wear depth is consistent with the theoretical value of the model， which verifies the accuracy of the model. As the wear at the top of the rack teeth is the most serious， choosing the gear with larger displacement coefficient is conducive to reducing the wear of the rack tooth surface.

In order to investigate the effect of frictional heat on the wear resistance characteristics of polymeric acetabular materials, the tribological tests and wear numerical analysis of three common polymer acetabular materials were carried out under different synovial fluid temperatures. The study results show that XLPE and VE-XLPE exhibit superior wear resistance compared to UHMWPE in high-temperature, heavy load environments. The coefficient of friction of three materials gradually decreases as the temperature of the synovial fluid increases. The wear depth and wear volume of the three materials increased with the increase of the temperature of the synovial fluid, and the forms of wear at 46°C and 55°C were mainly adhesive wear and plastic deformation. The higher temperature of the synovial fluid accelerates the oxidative degradation of the material surface and generates oxidation functional groups, which leads to the breakage of C-C bonds in the surface molecular chains under the sliding shear effect, thus reducing the mechanical properties of the material. Specifically, the surface of the polymer material will soften at a higher ambient temperature, mainly due to the decrease of hardness, and then deteriorate in the friction property, and finally increase the wear rate. Ansys results showed that the volume wear of the three materials increased with the increase of synovial fluid temperature, and the trend could be approximately linear. Numerical calculations predict that VE-XLPE has the highest wear of 0.693 mm3 among the three materials at 37°C, followed by XLPE at 0.568 mm3 and UHMWPE with the lowest wear of 0.478 mm3. At higher synovial fluid temperatures (46°C, 55°C), VE-XLPE still has the largest wear volume among the three materials, while XLPE and UHMWPE have similar wear. The wear cloud pictures showed that the maximum wear volume occurred near the edge of the acetabulum. [ABSTRACT FROM AUTHOR]

The present study proposes the further validation of a simple mathematical procedure recently proposed by the authors to describe contact and wear evolution in line and point contacts. The procedure assumed that the maximum contact pressure could be determined using Hertz equations and a parabolic pressure profile. The contact half-width was obtained using the equilibrium equation and the Archard wear law. Several cases were selected from the literature, reporting experimental data or Finite Element simulations, and the results were compared to those obtained with the proposed approach. This paper confirms the reliability and potentialities of the proposed analytical procedure, which is capable of providing accurate solutions in case of frictional contacts and at the borders of the contact area, where the main discrepancies were found in the previous study. [ABSTRACT FROM AUTHOR]

Brush seals can improve engine performance by reducing leakage. Wear models of brush seals provide methods to predict wear and leakage. However, rotor eccentricity, radial deformation, and hysteresis effect of bristles are not considered systematically in the existing models, which may lead to large errors in some cases. To investigate the influence of rotor-stator eccentricity and radial deformation on the wear process and leakage performance of brush seal, a brush seal test was planned and executed, in which the air leakage rates were measured at different testing times and operating conditions, the eccentricity and radial deformation was measured using eddy current sensors. The test results showed that the eccentricity and radial deformation significantly affected the wear behavior and leakage performance. In the theoretical research, the abrasive wear equation is adopted to describe the material loss of bristles, and a simplified description is used to express the rotor-stator eccentric motions. To describe the effect of hysteresis on wear behavior, the deformation of the bristle pack is divided into rebounding deformation and locked deformation, and the two deformation modes are modeled separately. Then a brush seal wear model considering rotor-stator eccentricity and radial deformation is obtained, in which the hysteresis effect is especially represented. The wear model was verified quantitatively based on the brush seal test data, and the results show that there is an error of 20% with the calculated wear loss when rotor eccentricity, radial deformation, and hysteresis effect are comprehensively considered. In contrast, ignoring the hysteresis effect may increase the error by several times. This study provides a quantitative and practical method for predicting the wear and leakage of brush seals. [ABSTRACT FROM AUTHOR]

Material loss due to wear plays a key role in the service life of rubber components in various tribological applications, such as tires, shoe soles, wiper blades, to name a few. It also adversely affects energy consumption, economy, and CO2 emissions around the globe. Therefore, understanding and modeling the wear behavior of rubbers are important in the design of economic and environment-friendly rubber compounds. In this study, we investigated the effect of normal load and sliding velocity on the wear rate of rubber compounds widely used in the tire treads and evaluated the wear models previously proposed for rubbers to determine the best model to predict the rubber wear rate. The sliding wear rates of different types of Styrene-Butadiene Rubber (SBR) and Isoprene Rubber (IR) compounds on a broom finish concrete slab were measured for different sliding velocities and normal loads. The experimental results were used to evaluate and discuss different wear models proposed in the literature. A new empirical model was proposed to predict the wear rate by considering mechanical properties associated with rubber wear. The experimental results revealed that the wear rate of rubber compounds non-linearly depends on the normal load or friction force, while the effect of sliding velocity on the wear rate is not significant in the 20–100 mm/s range. Moreover, traces of both mechanical (abrasion) and chemical (smearing) wear were observed on all rubber compounds. [ABSTRACT FROM AUTHOR]

The non-elastic electrical contact between pantograph strip and wire, via a pantograph-rigid catenary system, results in much wear of metro strip. Every month, hundreds of thousands of strips are consumed in China due to the approximately 9900 kilometers of metro distance. Numerous instances of abnormal strip damage have been observed at the site, likely attributable to the uneven wear of strip. However, the cause of uneven wear on metro strip remains unclear to date. Hence, a wear model was developed based on the thermal equilibrium and wear mechanism, to investigate the uneven wear of strip in metro system. Various parameters, including contact force, electrical current, velocity, and copper content of the strip have been studied to explore their relationship with strip wear. Different laying structures, such as sine, half-wave, and folded line, exhibited varying degrees of uneven wear on the strip surface, with maximum depths observed at 4.20 mm per 104 km, 3.68 mm per 104 km and 1.02 mm per 104 km, respectively. The contact force holds the dominant position in metro wear, followed by current. Additionally, the wear rate also demonstrated sensitivity to the copper content of the strip. [Display omitted] • A unified strip wear model has been developed to clarify the uneven wear issue. • Three typical catenary structures have been considered and compared. • Optimized operating parameters have been proposed for avoiding uneven wear. [ABSTRACT FROM AUTHOR]

During the grinding process, the workpiece is not only cut by abrasive grains but adhesive wear also occurs due to high temperature and heavy load, reducing the surface quality of the workpiece. In this paper, a wear test method considering speed, force, wear coefficient, temperature and hardness was proposed. A new physical model of wear prediction was established based on the finite element method and numerical simulation technology. The wear test was carried out on a grinding machine. Comprehensive research on the relationship between the force, temperature, surface morphology and wear volume of the grinding process was studied. The relationship between workpiece speed, grinding depth, cooling lubrication conditions and wear volume of the grinding process was studied. The results show that the wear model can achieve numerical prediction and trend prediction of grinding temperature, surface profile and wear volume, with relative errors between the theoretical and actual values of wear and grinding temperature of 9.84% and 2.07%, respectively. This study provides support for wear prediction and surface quality control of the grinding process from the perspective of temperature and micro material removal. [ABSTRACT FROM AUTHOR]

The present study proposes the further validation of a simple mathematical procedure recently proposed by the authors to describe contact and wear evolution in line and point contacts. The procedure assumed that the maximum contact pressure could be determined using Hertz equations and a parabolic pressure profile. The contact half-width was obtained using the equilibrium equation and the Archard wear law. Several cases were selected from the literature, reporting experimental data or Finite Element simulations, and the results were compared to those obtained with the proposed approach. This paper confirms the reliability and potentialities of the proposed analytical procedure, which is capable of providing accurate solutions in case of frictional contacts and at the borders of the contact area, where the main discrepancies were found in the previous study.

Brush seals can improve engine performance by reducing leakage. Wear models of brush seals provide methods to predict wear and leakage. However, rotor eccentricity, radial deformation, and hysteresis effect of bristles are not considered systematically in the existing models, which may lead to large errors in some cases. To investigate the influence of rotor-stator eccentricity and radial deformation on the wear process and leakage performance of brush seal, a brush seal test was planned and executed, in which the air leakage rates were measured at different testing times and operating conditions, the eccentricity and radial deformation was measured using eddy current sensors. The test results showed that the eccentricity and radial deformation significantly affected the wear behavior and leakage performance. In the theoretical research, the abrasive wear equation is adopted to describe the material loss of bristles, and a simplified description is used to express the rotor-stator eccentric motions. To describe the effect of hysteresis on wear behavior, the deformation of the bristle pack is divided into rebounding deformation and locked deformation, and the two deformation modes are modeled separately. Then a brush seal wear model considering rotor-stator eccentricity and radial deformation is obtained, in which the hysteresis effect is especially represented. The wear model was verified quantitatively based on the brush seal test data, and the results show that there is an error of 20% with the calculated wear loss when rotor eccentricity, radial deformation, and hysteresis effect are comprehensively considered. In contrast, ignoring the hysteresis effect may increase the error by several times. This study provides a quantitative and practical method for predicting the wear and leakage of brush seals.

The die undergoing severe loads induces inevitable wear in the pressure forming process, and the wear of die arouses obsessions about the die's service lifetime. In order to predict the wear and lifetime for a pair of rollers in net-shape blade rolling process, this paper quantified the distributions and evolutions of the local wear over roller cavities based on the local contact load responses and predicted the lifetime which related to wear by a mathematical model. Firstly, the net-shape blade rolling process and the local contact load responses were summarized. Then, an improved wear model was provided based on the Archard formula, and the impact factors of the model were standardized by a regression analysis experiment. The transient wear distributions and evolutions over the roller cavities were enumerated, and the wear distribution for one rolling cycle was calculated based on wear accumulation effect. Finally, a lifetime prediction model was proposed to predict the service lifetime of the rollers according to the wear accumulation effect, and an experimental verification was carried out to validate the model. The results show that the wear model and lifetime prediction model can be used for investigating the wear and lifetime of the roller cavities for the net-shape blade rolling process. [ABSTRACT FROM AUTHOR]

Abstract—An approach to the nature of friction and wear of steel surfaces is presented. A kinetic wear model of steel surfaces considering the quality parameters of a surface layer is proposed. To determine the coefficients in the wear model, the linear regression analysis is used. The results of the wear tests after a few technological processing methods were applied on the friction surfaces of steels 40 KhN, 45, and 18 KhGT are provided. [ABSTRACT FROM AUTHOR]

In the process of conveying coarse-grained minerals, the internal flow-through passage components of mining pumps are subject to wear. The flow of coarse particles in such pumps is complex and changes constantly, making it necessary to study the non-steady-state wear characteristics and test the flow passage components. The evolution of the surface wear rate for the flow passage components during one third of a rotation cycle (120°) of a mining pump impeller with small, design, and large flow rates was analyzed in this study based on a discrete phase model (DPM). The flow that occurs during an entire rotation cycle of the impeller was investigated. The wear test was carried out with a small test pump with the same specific speed as and a similar structure to that of the deep-sea mining pump. The test results were compared with the numerical calculation results of the deep-sea mining pump obtained by using the same numerical calculation method and wear model, and the test wear area was found to be more consistent with the numerical calculation wear area. The results show that the numerical calculation method used in this article can more accurately predict the surface wear of the passage components of the mining pump and provides a suitable method for the prediction of the wear characteristics of the mining pump. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the coal mine transportation, the scraper conveyor chute is badly worn. However, the abrasion performance has not been well documented. In this study, the chute was wear tested under a single factor using a modified pin-on-disc apparatus, including normal load, sliding distance, bulk coal characteristics (water content, gangue content), and chute material. Experiments were also carried out with a simultaneous variation of these factors. Generally speaking, the influence of coal characteristics on the chute wear was obviously higher than that of normal load and sliding distance. An improved wear predict model was obtained taking the operational parameters and bulk coal characteristics into account. The wear mechanism involved micro-ploughing, corrosion, adhesion, and fatigue peeling. [ABSTRACT FROM AUTHOR]

The tribological tests of brass and steel are carried out on an in-situ tribometer. The Stribeck curve illustrates that the roughness and the wear rate as a whole reflect the lubrication regimes. Under boundary lubrication, a mathematical model based on positive pressure and roughness is established. A good agreement between the measurement and the prediction is found. According to the analysis of worn surface morphology, the main wear mechanism of brass is adhesive wear under boundary lubrication, which results in relatively high values of tribological parameters. The oxides strengthening layer is hardly generated under boundary lubrication until the experiment enters the mixed lubrication (ML) and the hydrodynamic lubrication (HL) regimes. [ABSTRACT FROM AUTHOR]

A theoretical study of piston ring wear in large two-stroke engines is presented. Piston rings in combustion engines are manufactured with an initially defined shape of the surface contacting the cylinder liner. Further the ring surface working against the cylinder liner is coated with layers of ceramic materials to accommodate the running-in process. Most rings have a nonflat shape (parabolic) when delivered from the ring supplier. After running in which is typically many hours of operation(>1000 h) the ceramic layers are worn and the ring geometry is typically changed significantly by surface wear. It is shown in the present study that the geometry of the worn ring depends on the operation scheme of the engine. Both the load pattern and the order in which the loads are applied influences the final shape of the piston ring surface. [ABSTRACT FROM AUTHOR]

This paper devotes to providing a dynamic reliability model for linear guideways for the whole life. Since a linear guide is always worn, the wear degradation of the linear guide is established. Moreover, the profile error of rail is considered. To get the dynamic behavior of linear guides precisely, we developed a dynamic stiffness model of the system in terms of different load conditions and operation time. The reliability model with variant stochastic parameters is proposed according to the contact characteristics of linear guides. The Monte Carlo method is adopted to solve the reliability of linear guides. The simulation results show the reliability curve agrees with the experimental results, as well as the engineering experience in practice. The proposed model can be well applied to the reliability prediction for linear guideways. [ABSTRACT FROM AUTHOR]

In the process of conveying coarse-grained minerals, the internal flow-through passage components of mining pumps are subject to wear. The flow of coarse particles in such pumps is complex and changes constantly, making it necessary to study the non-steady-state wear characteristics and test the flow passage components. The evolution of the surface wear rate for the flow passage components during one third of a rotation cycle (120°) of a mining pump impeller with small, design, and large flow rates was analyzed in this study based on a discrete phase model (DPM). The flow that occurs during an entire rotation cycle of the impeller was investigated. The wear test was carried out with a small test pump with the same specific speed as and a similar structure to that of the deep-sea mining pump. The test results were compared with the numerical calculation results of the deep-sea mining pump obtained by using the same numerical calculation method and wear model, and the test wear area was found to be more consistent with the numerical calculation wear area. The results show that the numerical calculation method used in this article can more accurately predict the surface wear of the passage components of the mining pump and provides a suitable method for the prediction of the wear characteristics of the mining pump.

The article presents the method of determination of life and reliability of rail vehicles wheels on the basis of the wear model developed on the basis of laboratory tests results. The method allowed quantitative assessment of the impact of various factors on the life of the wheels due to flange and tread wear. It was stated that the most significant impact on life resulting from the flange wear is exerted by the share of curves in track length, whereas life due to tread wear - longitudinal creepage of the tread with regard to the rail. The reliability assessment was performed using the Monte Carlo method. It allows to take into account randomness of both interaction conditions and the wear process. The determined reliability was described by the Weibull's distribution. The calculations were made for the ET41 series electrical freight locomotives. The method presented in this work can be suitable for preparation of schedules of wheel repairs and thus contribute to the increase of ride safety and comfort and therefore to the decrease of the costs of maintenance of the rail vehicles. [ABSTRACT FROM AUTHOR]