Wear Process Research Articles

A Novel Catalytic Ceramic Conversion Treatment of Zr702 to Combat Wear

Zr and its alloys are widely used in multiple areas, including the nuclear and medical fields. Previous studies indicate that a ceramic conversion treatment (C2T) of Zr-based alloys can address the issues of low hardness, high friction, and poor wear resistance of Zr based alloys. This paper introduced a novel catalytic ceramic conversion treatment (C3T) to Zr702 by pre-depositing a catalytic film (such as silver, gold, platinum, etc.) before the ceramic conversion treatment, which efficiently promoted the C2T process, in terms of reduced treatment times, with a thick, good quality, surface ceramic layer. The formed ceramic layer significantly improved the surface hardness and tribological properties of Zr702 alloy. Compared with conventional C2T, the C3T technique provided two orders of magnitude reduction of wear factor and reduced the coefficient of friction from 0.65 to <0.25. Among the C3T samples, the C3TAg and the C3TAu samples have the highest wear resistance and lowest CoF, mainly due to the self-lubricant formation during the wear processes.

On the Wear Behavior of Bush Drive Chains: Part I—Characterization of Engine Damage Processes and Development of a Model Test Setup for Pin Wear

The present work deals with the tribological characterization of the bush-pin contact in timing chains, with a particular focus on the pin wear processes and the development of a model testing technique suitable for this purpose. With the presented test methodology, both the friction and other parameters, such as contact temperatures and the electrical contact resistance between the CrN-coated pin and a steel bush equivalent could be precisely measured during the test procedure, and the input parameters, such as test load, temperature, and test frequency, could be specifically adjusted. In addition, motor components were analyzed in the present study, in order to study the damage processes of application and compare them with those of the model tests. The measured friction and wear processes on the test rig were verified using well-acknowledged design parameters, such as apparent friction energy and linear wear intensity according to Fleischer. The results demonstrated the wear process between the CrN coated spherical steel surface and the plane steel counterpart (mild smoothing wear at moderate loads, and for an advanced wear state with an exposed steel substrate, there was exposed break-outs and deformation, as well as abrasive grooving) and showed that the methodology replicated the wear processes of application and is therefore suitable for characterizing the pin wear of bush drive timing chains.

Modellversuch für die experimentelle Untersuchung des Verschleißverhaltens des Gleitschuh-Schrägscheibe Kontakts

In axial piston pumps, hydrostatically partially balanced contacts are predominantly used. The use of these pumps in variable-speed configurations, such as in electro-hydrostatic axes, has proven to be very challenging in terms of robustness. Particularly affected here is the slipper-swashplate contact, via which the piston loads are supported. The wear processes and driving effects occurring here have not yet been sufficiently addressed in the current state of research. Within the scope of this publication, a model experiment is therefore to be presented which allows the targeted investigation of the wear behaviour of the slipper-swashplate contact under controlled and reproducible conditions. The objectives of the model experiment are, on the one hand, the empirical investigation of the interactions in variable-speed operation and, on the other hand, the validation of simulative considerations.

Effect of Nanoparticle Concentration on the Performance of Ni-Co-β-SiC Composite Coatings Electrodeposited on the Surface of Spindle Hook Teeth

This study aimed to improve the surface hardness and wear resistance of spindle hook teeth with special shapes to reduce the cost of replacing the spindle on cotton pickers. For this goal, a Ni-Co-β-SiC composite coating with different concentrations of β-SiC nanoparticles (0, 1, 2, 3, and 4 g/L) was electrodeposited on the surface of spindle hook teeth. The hardness, elemental composition, and micromorphology of the spindle hook teeth were characterized by microhardness tests, an energy spectrum analyzer, and a scanning electron microscope after cutting with the spindles. The actual wear process of the coating was determined by wear simulation and scratch wear tests, and the effect of the concentration of β-SiC nanoparticles on the properties of the coating was investigated. The results show that Ni-Co-β-SiC composite coating has a typical cellular structure. The hardness first increases and then decreases, and the wear resistance (including friction coefficient, scratch area, and shape of wear area) first decreases and then increases, mainly due to the pinning role and agglomeration of β-SiC nanoparticles. When the concentration of β-SiC was 1 g/L, the hardness reached a maximum of 506.2 HV0.1, the coefficient of friction reached a minimum of 0.13, and the wear area and wear micromorphology reached the most suitable values. Therefore, this Ni-Co-β-SiC composite coating had the best microhardness and wear resistance.

Experimental Investigations on Erosion-Corrosion Characteristics of HVOF-Sprayed WC-10% Ni Coatings Deposited on Aluminum Alloy

The current work investigates the erosion-corrosion behaviour of thermally sprayed tungsten carbide-10% nickel (WC-10% Ni) coatings placed on the AA6061 aluminum alloy. The AA6061 aluminum alloy was coated with tungsten carbide –10% nickel coatings utilising a high-velocityoxy-fuel (HVOF) spray method. The microstructure and hardness of thermally sprayed coatings were examined using a scanning electron microscope (SEM) and a Vickers hardness tester. The slurry erosion-corrosion wear tests were carried out by varying the parameters of the slurry erosion process, such as testing time, slurry content, slurry speed, and impinging particle size, on the erosion testing equipment. The data demonstrated that when slurry concentration, slurry speed, and impinging particle size increased, so did the slurry erosion-corrosion wear loss. The wear processes of uncoated and thermally sprayed tungsten carbide –10% nickel have been examined using SEM and a 3-D confocal microscope.

Technological Aspects of Variation in Process Characteristics and Tool Condition in Grinding Process Diagnostics

The article presents the technological aspects of the diagnostics of grinding processes. The main features of the grinding process and their importance in diagnostic issues are discussed. Selected issues of research and assessment of the condition of the active surface of grinding wheels are presented. The authors pointed out that the parameters used to assess the topography of the ground surfaces do not have sufficient possibilities to differentiate the surface condition of the grinding wheels. This publication draws attention to the possibility of using new dedicated parameters to assess the properties of the grinding wheel surface. These parameters have a high ability to differentiate changes occurring as a result of the abrasion of grain vertices, their chipping or loading of the grinding wheel surface. The methodology of assessing the processes of abrasive grain wear and changes in the shape and dimensions of the grinding wheel, taking into account the probabilistic features of the grinding process, was formulated. The directions for the development of abrasive tools are presented, pointing to hybrid tools with a multi-phase structure, modified by additions of abrasive aggregates. A new research direction has also been formulated on the use of additive technology to produce specialised abrasive tools, including those with built-in process sensors.

Structural design and high temperature tribological behavior of a new turbine blade tip protective coating

Severe damage to the blade tip usually occurs when the turbine blade tip scratches against the abradable coating. Therefore, blade tip strengthening is a hot research topic. To improve the wear resistance of turbine blade tips, NiAlTa coatings were prepared on K417G superalloy by electro spark deposition. The microstructure and phase composition of the coating were analyzed by scanning electron microscope and X-ray diffraction. Microhardness tester and scratch method were used to test the microhardness and bonding strength of the coating. Using ZrO2 balls as friction pair, the tribological behavior and wear mechanism of the coating were investigated by a self-developed tribometer at 25 °C and 800 °C. The NiAlTa coating mainly consists of the β phase NiAl and the laves phase NiTaAl. The laves phase NiTaAl encapsulates the NiAl phase, and this plant-like “cell wall” structure endows the coating with excellent mechanical properties, wear resistance, and cutting performance. Compared with the substrate, NiAlTa coating has higher microhardness (~797.18 HV0.2) and lower wear rate (~10−6 mm3·N−1·m−1). The wear process of NiAlTa coatings is dominated by plastic deformation, with little evidence of material loss from the brittle fracture. The competition between the anti-wear lubricating effect of the “glaze” layer and the plowing effect of oxides and ZrO2 debris affects the tribological behavior of the coating. The cutting performance of the NiAlTa coating can be attributed to the two-body or three-body abrasive wear caused by the oxides and ZrO2 debris embedded in the “glaze” layer.

Breakdown of Reye’s theory in nanoscale wear

Building on an analogy to ductile fracture mechanics, we investigate the energetic cost of debris particle creation during adhesive wear . Macroscopically, Reye proposed in 1860 that there is a linear relation between frictional work and wear volume at the macroscopic scale. Earlier work suggested a linear relation between tangential work and wear debris volume also exists at the scale of a single asperity, assuming that the debris size is proportional to the micro contact size multiplied by the junction shear strength. However, the present study reveals deviations from linearity at the microscopic scale. These deviations can be rationalized with fracture mechanics and imply that less work is necessary to generate debris than what was assumed. Here, we postulate that the work needed to detach a wear particle is made of the surface energy expended to create new fracture surfaces, and also of plastic work within a fracture process zone of a given width around the cracks. Our theoretical model, validated by molecular dynamics simulations, reveals a super-linear scaling relation between debris volume (Vd) and tangential work (Wt): Vd∼Wt3/2 in 3D and Vd∼Wt2 in 2D. This study provides a theoretical foundation to estimate the statistical distribution of sizes of fine particles emitted due to adhesive wear processes.

SLIDING WEAR BEHAVIOR OF MARBLE DUST PRE-MIXED WITH NiCr COATINGS ON MILD STEEL SUBSTRATES AT ELEVATED TEMPERATURE

In this research, microsized marble dust is spray-coated on mild steel substrates through a well-designed high-velocity oxy-fuel (HVOF) spraying route. For this, a standard spray set up Hipojet 2700 is used. Marble dust is an ornamental stone waste generated in huge quantities during the depletion and processing of ornamental stones to make them usable. Commercially available spray-grade NiCr powder is added with a proportion of 10% by weight in the marble dust prior to deposition to increase its flowability and adherence. The coating on the mild steel substrates is deposited with a spray distance of 200[Formula: see text]mm and a fuel (LPG) feed rate of 55–60[Formula: see text]g/min. Dry-sliding wear trials under controlled conditions on the deposited coatings are conducted as per ASTM G 99-05 using a tribometer capable of operating at a wide temperature range. A parametric analysis of the test results using MINITAB 18 software shows that the control factors such as sliding velocity, specimen temperature, sliding distance and normal load, in the declining sequence, are significant in affecting the specific wear rate (SWR) of the coatings. Based on this, further experimentations are carried out separately for a wider range of the sliding velocity and specimen temperature keeping all other factors constant to study their individual effects on the wear rate more precisely. The morphologies of the worn surfaces are studied to ascertain the possible mechanisms taking place during the wear process leading to coating mass loss.

Study on milling tool wear morphology and mechanism during machining superalloy GH4169 with PVD-TiAlN coated carbide tool

Tool life, dimension accuracy and surface quality of workpiece, intelligent operation and maintenance of automated production are closely related to tool wear. However, for many years, relevant scholars have mainly focused on the research of the tool wear mechanism in the sharp wear stage, mainly involving various machining methods, various superalloy materials, various tool materials and geometric parameters, and different coolant methods et, al. The morphology and mechanism of tool wear need to be further studied in the initial and steady wear stage, which is helpful to ensure the dimensional accuracy and surface quality of workpiece, especially in the finishing stage. 45 groups of tool wear experiments are carried out under dry condition during milling of GH4169 with PVD-TiAlN coated carbide tools. The tool wear micro-topography, tool wear curve, tool cutting force, spindle motor current, tool wear mechanism, chip topography and machined surface topography were investigated during the milling tool wear. The tool wear mechanism in the sharp wear stage was further explored by SEM, EDS and XRD, which will help to deeply gain the milling characteristics of GH4169 and help to test the cutting performance of the tool. The results show that during the tool wear process of milling superalloy GH4169, severe abrasive wear and adhesive wear occur in large numbers, the rate of tool wear is fast, the cutting force increases, the current of the spindle motor increases, and the tool coating and substrate material were worn seriously, the main tool wear mechanisms are abrasive wear, adhesive wear, oxidative wear and breakage. Severe abrasive wear occurs between lots of hard abrasive carbides in the workpiece material and the rake and flank faces of the milling tool. Fe, Cr, Al, etc. were found on the rake and flank faces, and the adhesive wear was very serious. Many oxides (Al2O3, Fe2O3, etc.) appear on the rake and flank surfaces, which indicate that oxidative wear occurs. Due to the periodic intermittent cutting during the milling process, the breakage of milling tool edge is very serious. Chips or adherents with different microscopic topographies were adhered to the tool wear area due to extrusion and stretching in the sharp wear stage. The machined surface micro-topography of the workpiece, which affected by tool wear, was greatly of difference during the entire wear stage.

Aluminum Nanoparticles Affect Human Platelet Function In Vitro.

Endoprostheses are prone to tribological wear and biological processes that lead to the release of particles, including aluminum nanoparticles (Al NPs). Those particles can diffuse into circulation. However, the toxic effects of NPs on platelets have not been comprehensively analyzed. The aim of our work was to investigate the impact of Al NPs on human platelet function using a novel quartz crystal microbalance with dissipation (QCM-D) methodology. Moreover, a suite of assays, including light transmission aggregometry, flow cytometry, optical microscopy and transmission electron microscopy, were utilized. All Al NPs caused a significant increase in dissipation (D) and frequency (F), indicating platelet aggregation even at the lowest tested concentration (0.5 µg/mL), except for the largest (80 nm) Al NPs. A size-dependent effect on platelet aggregation was observed for the 5-20 nm NPs and the 30-50 nm NPs, with the larger Al NPs causing smaller increases in D and F; however, this was not observed for the 20-30 nm NPs. In conclusion, our study showed that small (5-50 nm) Al NPs caused platelet aggregation, and larger (80 nm) caused a bridging-penetrating effect in entering platelets, resulting in the formation of heterologous platelet-Al NPs structures. Therefore, physicians should consider monitoring NP serum levels and platelet activation indices in patients with orthopedic implants.

Time-Varying Wear Calculation Method for Fractal Rough Surfaces of Friction Pairs

For the wear problem of the real rough surface during sliding friction, based on fractal theory and Hertz contact theory, a 3-D fractal rough surface with random characteristics is constructed, and the relationship between the wear deformation depth of the rough peak and its real contact area during the wear process is derived. Furthermore, considering the peak wear and pit scratch phenomena of rough surfaces in different contact states, the time-varying wear calculation model of the worn surface and the compensation wear calculation model of the unworn surface are established, respectively, and the relationship between the instantaneous wear amount and the dynamic change in the rough surface topography is comprehensively characterized. Combined with image digitization technology, the 3-D rough surface is converted into a 2-D discrete plane with 3-D information. According to the dynamic real-time update of the graph data, the iterative calculation of the wear cycle is completed, the time-varying wear calculation method for fractal rough surfaces of friction pairs is proposed, and the dynamic change in the wear amount and surface topography of the rough surface is simulated. The simulation results are experimentally verified and the influence of friction parameters on the surface topography is analyzed. The results show that after the wear simulation, the profile height of the rough surface is reduced, and the average wear depth is 0.02 mm. Increases in rotational speeds and external loads can exacerbate surface wear, surface topography tends to be flattened, and surface carrying capacity increases. This provides theoretical guidance for the development and manufacture of friction pairs.

A quantitative model that correlates sharpness retention and abrasive wear of knife blades

The relation between sharpness retention and the wear of knife blades is a fundamental technical problem to be elucidated in industry, as it can help improve the design of knife blades and extend their service time. In this study, the wear mechanism of steel blades with varied blade angles were investigated following classic wear methodology. Simple linear relationship between actual applied force F, cycle number n and volume of material loss Vloss were found and analyzed. The wear rates (1.5–1.98 × 10−4 mm3/(Nm)) and wear constant K (∼10−3) were determined, and the wear process the blade tip suffered was identified as three-body abrasive wear. Moreover, the sharpness retention of a blade was evaluated via the Cumulative Cutting Depth (CCD) of paper cards, which closely correlates to the evolution of blade tip geometry. The cutting mechanism was found to shift from cutting-up to wear-out as the contact pressure underneath the blade tip falls below a critical value, e. g 136 MPa for the paper cards. Considering both these two cutting mechanisms, a generalized quantitative model has been established to describe the CCD in terms of wear resistance of materials, blade angle and initial width of blade tip.

Fretting wear behavior of Inconel 718 alloy manufactured by DED and treated by UNSM

Alloy 718 is commonly used in the maritime and aerospace industries due to its strength and durability, particularly in engine rotating components such as disks, fan blades, and high-pressure compressors. As a new type of 3D printing technology, directed energy deposition (DED) can employ lasers to melt metal powders or wires to fabricate arbitrary-shaped workpieces directly from customized data, thereby making machining more synergistic and intuitive. However, the surface properties of the DED-printed alloy 718 samples, such as surface roughness and wear resistance, are typically subpar. By introducing severe plastic deformation to the near-surface, ultrasonic nanocrystal surface modification (UNSM) can be used as a post-processing method and results in altered properties. The uniaxial tensile test reveals that the UNSM-treated alloy 718 exhibits a higher mechanical property. Moreover, using a fretting test rig in accordance with the cylinder-on-plane agreement, a higher wear resistance for UNSM-treated alloy 718 is observed. This study employs the finite element method to fully comprehend the effect of UNSM on wear performance. The fretting wear process of Inconel 718 alloy is established using an energy-based finite element model. Considering the severe practical scenarios, the Johnson–Cook constitutive model is implemented, with the linear isotropic hardening model capturing the plastic behavior. In comparison to experimental measurements, the finite element results demonstrate unprecedented wear loss consistency with an error of less than 2%. Therefore, we conclude that the finite element model built in this study exhibits a high accuracy and can be used to analyze the effect of UNSM on fretting wear behavior. According to finite element analysis, as the normal load increases, the improvement in wear resistance induced by UNSM decreases. Given that the finite element model is based on the energy method, the effects of coefficient of friction (COF) and wear coefficient modified by UNSM are investigated separately. According to the findings, the UNSM-modified COF and wear coefficient play a significant role in determining the wear characteristics. Due to the removal of a substantial amount of material from the central area of the alloy 718 surface by wear, it is also possible to observe that severe plastic strains are primarily concentrated at the edges of the wear scars.

Assessment of Residual Useful Life of Sun Gear in a Planetary Gearbox Based on Dynamic Wear Behaviors Analyses

For proactively arranged downtime and maintenance of the gearbox, the accurate assessment of residual useful life (RUL) for worn-surface gear is a critical problem that needs to be solved. In light of this, a novel dynamic assessment methodology for RUL of sun gear was proposed by coupling Archard’s wear model and a nonlinear dynamics model. By modifying the internal excitation model, the effect of tooth surface wear is included in the dynamics model. Then, the effect of dynamic behavior on the wear process of the tooth surface is further fed back by the dynamic meshing force. On this basis, the influence of input speed, torque load and initial wear depth on the RUL was analyzed using a planetary gear NGW11-6 as an example. The results indicate that the torque load has the greatest influence on the RUL, followed by the initial wear depth, and that the input speed has the least influence. The established methodology will provide a theoretical basis for the RUL assessment and scheduled maintenance of transmission systems with worn-surface gears.

FORECASTING THE WORK RESOURCE OF THE RAILS IN DIFFERENT CONDITIONS OF OPERATION OF THE RAILWAY TRACK

In different operating conditions of the railway track, the service life of the rails is different. This indicates that there are external factors that have a significant impact on the process of rail wear. In the work, the analysis of influential factors was carried out and their degree of influence was determined in comparison with each other and in the statistical population.&#x0D; To study this problem, the most difficult section of the Slavsko-Lavochne-Beskid-Volovets track on the regional branch of Lviv Railway was chosen. The collection and processing of statistical data was carried out, measurements of the rail track and measurements of rail wear were carried out.&#x0D; The process of lateral wear of the rail depends on various factors, among which it is possible to single out those that are the same for the entire curve, and those that are different for different intersections of the curve. For the entire curve, the tonnage passed, the radius, the set speed, the rise of the outer rail, the longitudinal slope, the type of rails and the binding are the same. These parameters can be called global for the curve, and the wear that depends on them is global. Along the curve, there are local irregularities, that is, deviations in the plan, profile, pattern and inclination of the rail in the middle of the track. These parameters can be called local for the curve, and the wear that depends on them is local. Local wear is additional. The total side wear can be manifested to a greater or lesser extent depending on external conditions: lubrication, sanding of rails, excessive impact of wheels, which is taken into account by the coefficient of external conditions.&#x0D; The results of track measurements show that when a horizontal unevenness appears on a curved section, the bending radius increases, and in such places, there is an increase in lateral wear. When the width of the track in the curves exceeds the established norms, there is also an increase in the amount of wear. Over-inflating causes the wheelset to slide to the inner rail. At the same time, the larger rolling circle is not on the outer wheel, but on the inner one. The vertical force transmitted from the wheel to the rail is also greater along the inner thread. This leads to slipping of the wheel on the outer thread, which increases the lateral wear of the rail. As the measurements showed, when the slope of the rail increases from 1:20 to 1:10, the amount of lateral wear increases. The use of lubricators that lubricate the side surface of the rail head can increase its service life by 3 times. An increase in the surface roughness of the rail by 20 μm leads to a decrease in wear resistance by 20-25%. Based on the received empirical data, a mathematical model of lateral wear of the rail head based on 16 parameters was created.&#x0D; Based on the norms of permissible wear of the rails and the created mathematical model, the service life of the rails is determined in the work depending on the curvature of the track. Forecasting the resource of rails allows to implement resource-saving in railway transport.

The tribological properties of two-phase hard and soft composite wear-resistant coatings on titanium alloys

There are still problems associated with the use of conventional modified coatings on titanium alloys despite their attempts to improve wear resistance. These problems include incompatibility of mechanical properties, a poor interface bond, and an abundance of debris. The development of wear-resistant coatings with high reliability and long life is a vital component of expanding the use of titanium alloy in medical implants. The purpose of this study was to produce a composite coating with antifriction and wear-resistant properties by combining the high hardness TiN layer with the soft phase lubricated Cu layer produced by ion implantation and electroless plating. The implantation of Cu ions provided the nucleation sites for electroless copper plating and improving interfacial bonding. There was a reduction in adhesive wear due to the composite coating. By comparing the tribological test results of the composite coating and substrate, the volume loss of coatings decreased by 95 % for the same sliding length, the wear rate decreased from 2.55 × 10−13 m3/N·m to 1.28 × 10−14 m3/N·m, the friction coefficient reduced by 10 % and smoother. As a result of the synergistic effects between the soft and hard phases in the composite coating, titanium alloy exhibited an enhanced wear resistance as the wear process progressed.

A Novel Carbide-Free Bainitic Heavy-Haul Wheel Steel with an Excellent Wear-Resistance under Rolling-Sliding Condition

With the rapid development of railways towards high speed and larger carrying capacity, the problem of wear and fatigue damage between wheel/rail is gradually becoming serious. However, traditional pearlite wheel/rail has reached the limit, which leads to more attention to developing a novel wheel/rail material. This study aims to report a novel carbide-free bainite wheel steel. The wear-resistance of novel steel was tested by a rolling-sliding wear experiment under heavy-haul condition and investigated the impacts of the running speeds on the damage mechanism of wear and fatigue. The results show that the yield strength of the bainite wheel was as high as 950 MPa and the hardness was 415 HV, which was superior to most of the reported typical wheel steel. During the process of wear, the surface damage of the wheel was mainly adhesive wear and fatigue damage, and the gradient strain layer (GS layer) was formed on the wheel surface. As the running speed increased, fatigue damage gradually became more serious than adhesive wear, and the shear stress and strain of the GS layer were enhanced. The higher thickness and hardening were produced on the GS layer, which is the main reason for the higher wear-resistance of the bainitic wheel under higher running speeds. In addition, the wear-resistance of the novel wheel steel was better than that of the reported wheel steel. This novel bainitic wheel is a promising wheel for heavy-haul condition applications, which could provide a guide in choosing bainitic wheel steel for the railway.

Combined analysis of acoustic emission and vibration signals in monitoring tool wear, surface quality and chip formation when turning SCM440 steel using MQL

With modern production, Minimum Quantity Lubricant (MQL) technology has emerged as an alternative to conventional liquid cooling. The MQLs is an environmentally friendly lubricant method with low cost while meeting the requirements of machining conditions. In this study, the experimental and analytical results show that the obtained acoustic emission (AE) and vibration signal components can effectively monitor various circumstances in the SCM440 steel turning process with MQL, such as surface quality and chip formation as cutting tool conditions. The AE signals showed a significant response to the tool wear processes. In contrast, the vibration signal showed an excellent ability to reflect the surface roughness during turning with MQL. The chip formation process through the cutting mode parameters (cutting speed, feed and depth of cut) was detected through analysis amplitude of the vibration components Ax, Ay and Az and the AE signal. Finally, Gaussian process regression and adaptive neuro-fuzzy inference systems (GPR-ANFIS) algorithms were combined to predict the surface quality and tool wear parameters of the MQL turning process. Tool condition monitoring devices assist the operator in monitoring tool wear and surface quality limits, stopping the machine in case of imminent tool breakage or lower surface quality. With the unique combination of AE and vibration analysis model and the training and testing samples established by the experimental data, the corresponding average prediction accuracy is 97.57 %. The highest prediction error is not more than 3.8 %, with a confidence percentage of 98 %. The proposed model can be used in industry to predict surface roughness and wear of the tools directly during turning

A Wear Calculation Method for Helical Gear Based on Irreversible Thermodynamics

Abstract The accurate prediction of wear depth is of great significance to the failure evaluation of gear transmission. At present, the traditional wear calculation method is still unable to accurately predict the wear depth of helical gears under variable working conditions. The present work proposes a novel wear depth prediction method of helical gear, which is based on the theory of thermodynamics and the degradation entropy generation (DEG) theorem. The method can be used in not only dry contact friction but also mixed elastohydrodynamic lubrication (EHL) condition. The degradation coefficient of helical gear material was determined by wear experiment. The advantages of using DEG theorem to calculate wear loss under variable operation conditions are demonstrated by wear experiment. Moreover, the influence of ignoring the update of tooth surface load on the calculation results in wear process is further studied. The results reveal that the wear depth prediction method of helical gear proposed in this work can obtain the consistent wear depth distribution with the traditional method. The results calculated by the traditional method are generally higher than the method in this paper, and ignoring the load update in the wear process will make the results larger. The prediction method of helical gear wear depth presented in this paper will be useful for accurately predicting the wear of helical gear.