Wear Calculation Research Articles

Research on wear detection mechanism of cylinder liner-piston ring based on energy dissipation and AE

In the field of cylinder liner-piston ring (CL-PR) wear calculations, the traditional calculation models are difficult to use as a guide for wear detection. Therefore, a new analysis model of CL-PR wear based on energy dissipation theory is established in this paper. By using a mixed lubrication equation and simulation modification method, a new characterization formula of CL-PR wear is theoretically established. The maximum error between its calculated results and the simulation results is only 1.167%. The qualitative relationship between the wear volume and the frequency band energy of the acoustic emission (AE) signal is established based on the energy conversion relationship. The AE signal acquisition platform of CL-PR wear is built on the EV80 combustion engine, and the Bayes Shrink method is used to set the threshold of large-amplitude disturbance AE events for noise reduction. The wear signal is processed by wavelet packet energy spectrum decomposition, and the resulting wear energy spectrum can better characterize the change of wear characteristics. The BP (Back Propagation) neural network is trained with the characteristic parameters of the energy spectrum, and the classification accuracy of training and finally experimental results reach 98.6% and 100%, respectively, proving that AE technology can be applied to CL-PR wear monitoring combined with the neural network.

Carbon brush wear calculation in marine environment based on temperature field analysis

In the marine environment, the working environment of the doubly fed wind generator carbon brush and slip-ring system is complicated, salt spray deposits and seawater erosion affect the temperature field and contact surface friction factor leading to carbon brush wear increase and shortened replacement cycle. The three-dimensional temperature field simulation model of the carbon brush and slip-ring system is established. The main factors affecting the carbon brush and slip-ring system temperature field are sliding velocity, load current, ambient temperature, contact surface condition and contact pressure applied to the brush. Wear capacity of carbon brushes is affected by contact surface temperature. An experimental platform combined with the salt spray test machine was built to carry out the contact current, contact pressure, salt spray concentration and experimental temperature experiment. The improved Coulomb-viscous friction force model was used for the wear prediction model. The sliding velocity, contact pressure, contact current, experimental temperature and salt spray concentration were introduced into the model. The experimental verification has shown that the prediction model can effectively predict the carbon brush wearing capacity under different conditions. This model can be applied to formulating the carbon brush wear amount and replacement cycle in the marine environment reducing operation and maintenance costs.

Application of Kriging Model to Gear Wear Calculation under Mixed Elastohydrodynamic Lubrication

The calculation of tooth wear under mixed elastohydrodynamic lubrication is very complex and requires consideration of many conditions such as load distribution in the tooth meshing zone, micro-convex elastoplastic deformation and tooth surface temperature. The accurate calculation of tooth wear requires a lot of time and effort. In order to calculate tooth face wear under mixed elastomeric flow lubrication quickly and accurately, a new proxy model of tooth face wear is developed using the Kriging method. The pressure distribution required for the wear calculation was obtained utilizing the modified Reynolds equation and ZMC elasto-plastic model. The numerical calculation model of gear wear was derived using the modified Archard wear model. The Kriging model was used to construct a proxy model between gear parameters and tooth wear, and the degree of approximation and goodness of fit of the Kriging model were investigated. The results are as follows. The wear depth at each position is different, the smallest at the pitch, the largest near the tooth root, and the pinion has a larger wear depth than the gear. The Kriging model is highly efficient and accurate in its computation and overcomes the shortage of excessive time spent on the calculation of numerical calculation models.

Adaptive finite element simulation and experimental verification for fretting wear of PVDF piezoelectric thin films

An adaptive finite element method linked with user-defined subroutine UMESHMOTION is developed for simulating the tangential fretting wear of PVDF piezoelectric thin films. The three-dimensional (3D) sphere-on-flat contact model is established for the fretting wear simulation by using commercial software ABAQUS, where the Si3N4 ceramic ball is used as the punch in contact with PVDF piezoelectric thin films. The variable friction coefficient obtained from experiments is taking into consideration. The calculation of wear is based on the Archard's wear model. The tangential fretting motion with different loads and variable friction coefficients are applied in the finite element simulation. The fretting wear test are carried out to verify the numerical results under the same conditions. The results indicate that the present adaptive finite element model has a certain accuracy comparable to the experiment results for the fretting wear of PVDF piezoelectric thin films.

Wear calculation and life prediction model of disc brake based on elastoplastic contact mechanics

For the friction and wear of the braking surface of the disc brake, the mechanism of friction contact deformation of rough surface is analyzed. Considering elastoplastic contact mechanics of the friction surfaces, combined with Archard wear calculation theory, a wear calculation model of fractal rough surface is established, and a wear life prediction of the brake disc is proposed. Based on high-speed and heavy-load braking conditions, the influence of different braking parameters on the surface wear of brake disc is studied. Moreover, a pin-on-disc wear test is used to verify the validity of the wear calculation model, and the average relative error of test and simulation is 4.97%. The research results show that the fractal parameters affect the complexity of the rough surface, and surface wear is mainly caused by interface plastic contact. The friction coefficient is large, which can strengthen the surface shear effect. Large load and high speed would increase the real contact area of the surface and increase the wear volume per unit time. Furthermore, the wear life of the brake disc could be estimated, which is of great significance for raising the wear life of the brake disc, improving braking life and braking efficiency.

Study of the Two-Phase Flow and Wear of a Pump with Mixed-Size Particles

This paper used a combination of numerical simulations and experiments to study the hydraulic performance and the wear law of a centrifugal pump when conveying mixed particle sizes. The numerical simulation was based on the Discrete Phase Model (DPM). The model was used to complete the mutual coupling between the solid particles and the flow field as well as the calculation of wall wear. The results show that under the same mass concentration, the head and the efficiency of the centrifugal pump were significantly improved with an increase in the small particle composition. Compared with transporting single-sized large particles, the wear law of the mixed particle size on the flow parts changed greatly. The addition of a certain number of small-sized particles to large-sized particles aggravated the wear of the impeller, but when the small particles occupied a relatively high proportion, the wear area of the impeller was reduced even smaller than that for the transportation of single-sized large particles.

Dynamic Response of a Hypersonic Rocket Sled Considering Friction and Wear

The dynamic response of a hypersonic rocket sled was studied by considering the time-varying friction coefficient and the gap caused by wear between the slipper and track. A multibody dynamic model for a hypersonic rocket sled system was established by considering the time-varying mass and moment of inertia, nonlinear aerodynamic loads, engine thrust, track irregularity, and nonlinear contact force. As for the wear calculation, the ductile and shear criteria were used as the material damage criteria, and slipper wear was determined by the number of damaged elements. A rocket sled test was also carried out, and the dynamic response of the sled was measured. The results showed that the computational sliding displacement and velocity of the third-stage sled matched well with the test values. The computational root mean square (RMS) values of the vertical acceleration of the third-stage sled front slipper considering friction and wear matched better with the test values than with the case without considering friction and wear, which underestimated the RMS value by approximately 20.1% at Mach 5. The importance of considering friction and wear and the correctness of the computational method were validated. It is also found that the kinetic friction coefficient decreased with an increase in the product of the pressure and velocity. The wear height of the slipper increased almost linearly with the sliding displacement. The test results showed that the vertical acceleration power spectral density of the third-stage sled front slipper increased with time in the full frequency band below 2000 Hz. This study will guide the design and optimization of hypersonic rocket sleds.

The superior accuracy of a novel method in total hip wear calculations following radiographic measurement

BackgroundPolyethylene wear is one of the major concerns of orthopedic surgeons. However, there is no standardized calculation method for the wear rate following radiographic measurement. The purpose of this study was to propose a novel method of wear calculation and to compare its accuracy with a representative conventional method.MethodsRelative position of the center of the femoral head to that of the cup progresses in one direction following arthroplasty surgery because of bedding-in and wear. We predetermined the amount of bedding-in, wear rate, and random error in measuring the head center position in a 2-dimensional plane. We calculated the wear rate using the head center coordinates over a certain number of measurement periods using a representative conventional method and our novel method. The conventional method consisted of transforming vector data into scalars and conducting a least-squares method. The least-squares method was directly applied to each component of the vector in the novel method. We evaluated the accuracy of these methods by comparing the expected value for the wear rate with their predetermined true values.ResultsIf the error were limited to being random, the novel method could provide the predetermined wear rate as the calculation result. However, the conventional method could not.ConclusionWe recommend using the novel method for the wear calculation rather than the conventional method because of its mathematical accuracy.

An Experimental Study of the Wear Characteristics of Tubulars Made from Corrosion-Resistant Alloys

Summary Casing wear is the process of progressive loss of wall thickness owing to relative motion between the drillstring and casing. The amount of casing wear depends on conditions, such as the downhole forces, the accumulated time of contact between drillstring and casing, and the materials used. This process is complex and involves abrasive, adhesive, and corrosive wear mechanisms that are difficult to predict. To deal with the complexity of the conditions, a simple but effective wear model is used in the industry to estimate tubular wear in drilling and intervention operations. The model is based on abrasive and adhesive wear, and the effects of corrosion are not considered. In addition, an empirical part of the model known as the correction factor is based exclusively on experimental carbon-steel test data. Tubulars made of corrosion-resistant alloys (CRAs) are known to exhibit abnormal wear characteristics. A series of experiments has been designed and performed to investigate the wear characteristics of CRAs. These experiments resulted in excessive wear factors for the CRA casing samples, demonstrating their susceptibility to wear. This study finds that omitting the correction factor from the calculation procedure can greatly improve wear estimates for some CRAs. Removing the correction factor results in a linear wear-work relationship that reflects the actual wear trends from test results. However, further studies are needed to confirm correction factors and more accurate wear calculation procedures for CRA tubulars in general.

Verschleißsimulation grenz- und mischreibungsbehafteter Wälzkontakte

This contribution presents an approach for the numerical wear calculation of rolling/sliding-contacts. The finite element method based simulation model of Winkler [1] is extended to include contacts subject to boundary lubrication in addition to contacts subject to mixed lubrication. Using the example of an axial cylindrical roller bearing and two load cases, wear-modeling results of the mixed and boundary lubrication regime are illustrated.

Совершенствование методики тестирования износостойкости пар трения с переменным удельным давлением

The article is devoted to improving the method of testing the wear resistance of “block-on-ring” friction pairs. Simplified formulas for estimating linear and volumetric wear resistance based on decomposition into a Taylor series of geometric functions are proved. Particular attention is paid to the justification of linear wear based on the equivalence of the results in the calculation of volume wear. The dependence of volumetric wear resistance on linear resistance through specific pressure is proved. As a test of the proposed procedure, field tests of a number of materials of different hardness were carried out to determine the relative wear resistance of both linear and volumetric, as a result of which the effectiveness and advantages of the proposed method were justified.

Numerical calculation of wear in rolling contact based on the Archard equation: Effect of contact parameters and consideration of uncertainties

Wear in rolling contact is a complex phenomenon because it is multi-scale and multi-physical by nature and involves many strongly correlated parameters. It makes the numerical calculation of wear very challenging. In order to simulate wear, a better understanding of the influencing parameters involved in the wear calculation is of importance. This work presents a new numerical calculation of railway wheel wear based on Archard's equation combined with a spatial statistic approach called the Universal Kriging technique. The influence of factors, such as the contact mechanics model and the wear coefficient were studied through numerical experiments. The outcomes provide a new insight into the roles of the contact modelling and of the uncertainties of the wear coefficient in the numerical calculation of wear under various contact conditions. By considering the uncertainties of the wear coefficient, the approach provides a min.-max. range for wear estimation instead of a single deterministic value; furthermore, it can provide a detailed wear distribution over the contact patch for damage analysis. In combination with an accurate model of wheel-rail contact, this new wear model offers a more realistic wear prediction compared to the methods presently used for wheel wear estimation in railway vehicles.

A Review of Dynamic-Tribological Simulation Methods for Sliding Bearings in Internal Combustion Engines

The problem of friction reduction and wear resistance of sliding bearings is one of the key factors in determining the overall performance of internal combustion engines. This paper investigated and summarized the theoretical and simulation models of multi-body dynamics of crankshaft system, tribology of sliding bearings, and the wear calculation methods of the shaft-bearing friction pairs. Existing studies show that the dynamics model, hybrid lubrication model, and the friction and wear models request to be upgraded by comprehensively considering the material, structure, manufacturing process, working conditions, and etc. Based on the research status and existing problems of the above analyses, this paper summarizes the simulation models applicable to the field of dynamics and tribology of sliding bearings and presents the prospects for optimization of wear calculation methods for sliding bearings.

Lining Wear Measurements using a Coordinate Measurement Machine

<div class="section abstract"><div class="htmlview paragraph">Accurate measurements of brake friction materials are critical to understanding brake behaviors during testing. Current methods typically utilize a hand gauge (or a machine, in some cases) to sample various discrete points on the brake lining. This approach limits measurements to planar wear characteristics, taper and thickness, and excludes more complex measurements such as cupping. The limited number of points means that a single errant point measurement or the choice of point locations can have a large impact on the reported wear measurement.</div><div class="htmlview paragraph">This paper will describe a method for utilizing a Coordinate Measurement Machine (CMM) fitted with a laser line scanning tool to generate a point cloud of data that can then be compared to an earlier measurement of the same piece or to a math model. This method produces thousands of data points which allows for more accurate volumetric wear calculations and color maps of the entire friction face. A gage R&R for this method is presented along with some of the challenges involved in fixturing and aligning brakes pads for analysis.</div></div>

Experimental investigation and optimization of tribological properties for worm gear with different additives percentage of lubricating oil: A review

This paper presents are view of the study of tribological analysis of wormgear. The worm gear continuously suffers fromsliding motion, which causes friction loss and also wears of the gear tooth. To avoid friction energy loss and wear of gear lubricating oil is used. Lubricant oil creates a thin layer between teeth and avoids direct contact with teeth. Wear of the teeth must be minimum. Lubricant oil reduces wear as well as friction energy loss. So, the study of the relation between lubricating oil and the wear of worm gear material is necessary. The study of the effect of lubricating oil on worm gear with different percentages of additives. FE modeling and analysis will carry with the FEA software package. Oil additive percentage, type of lubricating oil, and load as input parameters and varying each at different levels and calculation of friction and wear (Response parameter) for each different combination of input parameters are possible. For experimentation Pin on Disc setup will be used. The optimum solution can be realized with help of the GRA and Taguchi methods. ANOVA will be performed to show the relation of each input parameter on response parameters.

Calculation of wear of teeth of open tooth gears

Abrasive wear and, in particular, wear of gear couplings in the presence of abrasive particles is studied. Under conditions of contact abrasive wear, with an increase in steel hardness and carbon content, the volumes of single surface damages caused by crushing of abrasive particles decrease, while the process does not qualitatively change. The direct fracture of the material in wear continues to be decisive. Keywords: gear coupling, wear, adhesion, abrasive grains, loading, friction force x.ishmuratov@mail.ru

A Numerical Simulation of Fretting Wear considering the Dynamic Evolution of Debris for the Coated Contact Surface

Abstract In this paper, a multi-layer body model in which material properties and wear coefficient change with node coordinates is proposed, so that the wear profile is not restricted by the singularity of the interface of the coated contact pairs. The conversion rate of the adhered particles was obtained to describe the growth and expansion of the debris at the fretting interface based on experiments, and the wear model of coated contact pair considering the dynamic evolution of the debris layer was established. By comparing the previous experimental and computational results, the wear calculation method proposed in this paper is more reasonable to predict the wear profile of the coated contact pair. In addition, the influence of the debris layer on the wear depth, friction width, and contact pressure in the fretting process is analyzed, indicating that the existence of the debris layer can delay the wear process. Finally, the fretting wear life of the SCMV steel contact pair deposited with the W-DLC coating is estimated.

Development characteristics of corrugation at different passing speeds

By using the vehicle-track interaction model and the wear calculation model, the development characteristics of rail profile wear and the longitudinal characteristics of rail wear development of the track-vibration-absorber fastener tangential track at different passing speeds were analyzed. The results of rail profile wear analysis show that with the increase of iteration times, the wear ranges and wear depths of left and right rails at the corrugation trough/crest position are close. Meantime, the wear depths of rail profile and wave depth amplitudes at the corrugation trough/crest position in discrete passing speed modes are significantly lower than those in constant passing speed mode. The results of rail longitudinal wear analysis show that with the increase of vehicle running times, the characteristic frequencies of corrugation do not change under different passing speed modes, which reflects the fixed frequency feature of corrugation, and the irregularity levels corresponding to characteristics frequencies of rail longitudinal wear under the three passing speed modes show a decreasing trend in turn. Compared with the constant passing speed mode, the discrete passing speed modes can significantly decrease the rail profile wear and the development degree of rail wear at the characteristic frequencies.

A fast simulation algorithm for the wheel profile wear of high-speed trains considering stochastic parameters

A fast calculation algorithm for the wear evolution of wheel profiles is proposed and results presented with a high-speed train as an example. The dynamics simulation includes the calculation of the vehicle running on a short straight track with random irregularities and the vehicle passing various curves without track excitation. The penetration curves of wheel/rail contact are assumed as the shape of wear distribution in a contact patch, which are calculated after the update of wheel profiles and interpolated in each step of wear calculation. The total wheel wear is the sum of the wear caused by track irregularities and the wear under smooth tracks, such as the straight and curved lines. After each dynamic simulation, several loops for wear calculation and profile update are carried out to smooth the wear curve. Simulation results show that the calculated distribution and average of the wear depth and the equivalent conicity in a reprofile cycle are in good agreement with the measured results. The predicted and measured wear shapes agree reasonably well in the area near the tape circle. Moreover, the proposed method is at least 15 times faster than the traditional wear calculation method and it can consider the influences of the stochastic parameters of the wheel/rail contact.

Tire Wear Reduction Based on an Extended Multibody Rear Axle Model

To analyze the influence of suspension kinematics on tire wear, detailed simulation models are required. In this study, a non-linear, flexible multibody model of a rear axle system is built up in the simulation software MSC Adams/View. The physical model comprises the suspension kinematics, compliance, and dynamics as well as the non-linear behavior of the tire using the FTire model. FTire is chosen because it has a separate tire tread model to compute the contact pressure and friction force distribution in the tire contact patch. To build up the simulation model, a large amount of data is needed. Bushings, spring, and damper characteristics are modeled based on measurements. For the structural components (e.g., control arms), reverse engineering techniques are used. The components are 3D-scanned, reworked, and included as a modal reduced finite element (FE)-model using component mode synthesis by Craig–Bampton. Finally, the suspension model is validated by comparing the simulated kinematic and compliance characteristics to experimental results. To investigate the interaction of suspension kinematics and tire wear, straight line driving events, such as acceleration, driving with constant velocity, and deceleration, are simulated with different setups of wheel suspension kinematics. The influence of the setups on the resulting friction work between tire and road is examined, and an exemplarily calculation of tire wear based on a validated FTire tire model is carried out. The results demonstrate, on the one hand, that the chosen concept of elasto-kinematic axle leads to a relatively good match with experimental results and, on the other hand, that there are significant possibilities to reduce tire wear by adjusting the suspension kinematics.