Wear Failure Research Articles

Research on early warning of rolling bearing wear failure based on empirical mode decomposition

In order to solve the problems of low precision and long time-consuming of traditional methods, this paper designs a rolling bearing wear fault early warning method based on empirical mode decomposition (EMD). Based on the wear reason of rolling bearing, the acceleration sensor is used to collect its vibration signal, and the EMD algorithm is used to stabilise the signal to obtain multi-scale signal. Each multi-scale signal is decomposed into sub-band to get multi-scale sub-band signal, then the multi-scale sub-band sample entropy is obtained, and the optimisation function of local preserving projection algorithm is constructed to obtain the eigenvalue and eigenvector of wear failure fault, and finally the fault early warning is realised. The simulation results show that the signal denoising effect of this method is good, the early warning accuracy is always above 94%, and the average alarm time is close to 0.27 s.

Reliability life analysis of blades of twin-shaft mixer based on wear failure

As an important part of mixing material, the study on the reliability life of the blade of mixer is very necessary. According to the Arcard wear formula, the mathematical model expression of the wear amount and the load on the blades of the twin-shaft mixer in a single cycle is established. The discrete element method is used to obtain the load on the blade in the mixing process. The law of load distribution of mixer blades is obtained by Lilliefers method. Furthermore, Lagrange interpolation method is used to analyze the static simulation results of the mixing blade, and the total wear amount when the blade reaches the critical thickness is obtained. By establishing the functional relationship between wear and blade life, Monte Carlo method is used to simulate the load distribution law to predict the reliability life of the mixer blade. The results show that the reliability of the life of the mixer blade is 85.02%.

Reliability Analysis for the Dependent Competing Failure With Wear Model and its Application to the Turbine and Worm System

Many systems are usually subjected to the combined effects of degradation and random shocks at the same time. Their failures are the competitive result of soft failure caused by degradation and hard failure caused by shocks. For operating machinery, wear failure is the main failure mechanism, and the machine is also subject to shock during the wear process. This paper proposes a new generalized surface wear model in combination with dependent competing failure processes; this proposed model is different from the other wear model with independent wear increments. As a typical mechanical structure, worm gears and worms are subjected to the combined effect of two failure mechanisms: soft failure caused by performance degradation, and hard failure caused by shocks. Meanwhile, it is necessary to consider the competitiveness and correlation of these two failure mechanisms. The interdependent competitive failure model is used to describe the failure of operating machinery. In this study, the extended Archard model is used to calculate the wear depth of the tooth surface, and the wear model is established through the wear threshold. The relationship between tooth surface wear depth and duty cycle, sliding speed, and contact stress is analyzed. An iterative algorithm is used to derive a nonlinear time-varying wear degradation model considering contact stress and sliding velocity. Comparing the calculation results with the Monte Carlo simulation method, the model has high accuracy and describes the mechanism of soft and hard failures, and the mutual dependence of the two failure mechanisms has an important effect on reliability. Numerical examples are presented to illustrate the developed reliability models, along with sensitivity analysis.

Research on early warning of rolling bearing wear failure based on empirical mode decomposition

Research on early warning of rolling bearing wear failure based on empirical mode decomposition

Friction-wear failure mechanism of tubing strings used in high-pressure, high-temperature and high-yield gas wells

This study establishes a flow-induced nonlinear vibrations (FINV) model of tubing string using micro-finite element and energy methods along with the Hamilton variational principle. This model helps address the wear failure of tubing strings caused by FINV in high-pressure, high-temperature, and high-yield (3H) gas wells and considers the changes in wellbore trajectory, wellbore temperature/pressure, and contact/collision of the tubing-casing. To validate the proposed model, a simulation experiment of tubing string vibration was conducted. Based on the White-Fleisher wear theory, a method is proposed for calculating wear amount and depth of tubing string in 3H gas wells; the friction coefficient and wear rate are determined via a wear experiment. Thus, the influences of production rate, inclination angle, well section length, packer position, and centralizer position on the wear characteristics of tubing string are systematically analyzed. The results obtained demonstrate that, first, with the increase of production rate, the wear life of the tubing string decreases, and there exists a sudden value of production rate, which can be determined using the proposed analysis method, such that the field production allocation should be far away from the sudden production rate. Second, in the well trajectory design, the vertical section length should be small, while that of build-up section and the angle of stable inclined section should be large. Third, the optimal positions for the packer and centralizer in the field depend on the well structure, downhole tool size, etc. and can be determined using the proposed analysis method; these positions help design field tools. The research results provide a theoretically sound guidance for designing and practically sound approach for effectively improving the service life of tubing string in 3H gas wells.

Machine learning based anomaly detection and classification of acoustic emission events for wear monitoring in sliding bearing systems

The present study aims at monitoring and classifying the multi-variant wear behavior of sliding bearings. For this purpose, acoustic emission (AE) technique was applied to a test rig for sliding bearings. AE signals were evaluated with machine learning methods in order to detect anomalies from a hydrodynamic bearing operation. Furthermore, a deep learning approach based on convolutional neural networks was used for multi-class classification into three different wear failure modes, namely running-in, inadequate lubrication and particle-contaminated oil. A high accuracy and high sensitivity have been achieved in the detection and classification of three-body abrasion due to particle contamination. In the cases of running-in and inadequate lubrication, the incubation period during the onset of inadequate lubrication is sometimes mistaken for running-in and vice-versa, which reduces the overall accuracy of the classification.

Evaluation of the main indicators of the reliability of the power transmission of a combine harvester John Deere 9660

The failure-free performance of the components determines the technical and economic efficiency of the use of the combine harvester. A low level of reliability leads to an increase in the cost of harvesting, the need for unscheduled repairs due to failures of parts, assemblies and assembly units. Studies have shown that a significant proportion of failures occur in power transmission units. In this regard, the aim of the work is to assess the reliability of the power transmission of the John Deere 9660 combine harvester. The average time between failures of the power transmission units was 80 hours, which does not meet the regulatory requirements (according to STO AIST 8.22 - 2010 - at least 100 hours). Failures of all powertrain assemblies are caused by a combination of failures: wear and fatigue failure of the bore holes for the bearings of the unit housings, and gears, bearings from dynamic loads.

One‐step preparation of the superhydrophobic Al alloy surface with enhanced corrosion and wear resistance

AbstractCorrosion and wear failures are bottlenecks for restricting applications and developments of Al‐based functional materials. As a new lubrication technology, superhydrophobic preparation provides an effective way to settle Al alloy corrosion. The preparation methods of superhydrophobic Al alloys are mainly multistep strategies. In this study, superhydrophobic Al alloy, has been prepared by an efficient one‐step electrochemical etching process. Meanwhile, its micromorphology has been observed by a scanning electron microscope. The wettability has been measured by video optical contact angle meter. The corrosion behavior has been tested by electrochemical workstation, and wear performance has been characterized by friction tester. The results show that the micro‐nanoterraced concave–convex structure has been fabricated and an as‐prepared surface exhibits excellent superhydrophobic behavior. Further electrochemical and tribological tests show that corrosion resistance and wear resistance have also been significantly improved. This study provides a new method to prepare wear‐resistant and corrosion‐resistant Al alloy for widening applications of multifunctional Al‐based engineering materials.

Friction behavior of PTFE-coated Si3N4/TiC ceramics fabricated by spray technique under dry friction

PTFE coatings were deposited on the Si3N4/TiC ceramic substrate by using spray technology. The surface and cross-section micrographs, adhesive force of coatings with substrate, surface roughness and micro-hardness of the coated ceramics were examined. The friction and wear behaviors of ceramic samples with and without coatings were investigated through carrying out dry sliding friction tests against WC/Co ball. The test results indicated that the coated ceramics exhibited rougher surface and lower micro-hardness, and the PTFE coatings can significantly reduce the surface friction and adhesive wear of ceramics. The friction performance of PTFE-coated sample was affected by applied load due to the lower surface hardness and shear strength of coatings, and the main wear failure mechanisms were abrasion wear, coating delamination and flaking. It can be considered that deposition of PTFE coatings is a promising approach to improve the friction and wear behavior of ceramic substrate.

Development of a method for wireless information transmission in wells equipped with sucker rod pump units

Oil lifting via sucker rod pump units is the most widespread way to extract oil reservoir products. Complications adversely affecting the operation of downhole equipment and entailing increased wear and premature failure of sucker rod pump units arise in the process of high-viscosity oil production. The pressure and temperature of the well fluid are the main parameters for assessing changes in the properties of the extracted products and for determining the static level of the liquid column. It is possible to control pressure and temperature using sensors located in the immediate vicinity of the well pump. Today, a wired channel is the main way of transmitting the measured data to the well mouth. The present work proposes a new technical solution for a wireless communication channel along tubing strings and rods. The columns are separated by asphaltenes deposits on the surface of the columns and centralizers mounted on the rods. The rod string isolation from the tubing string at the wellhead is carried out through suspension modernization. Columns are closed inside the pump, specifically, on the cylinder-plunger contact. Information is transmitted from the bottom by means of a submersible module, consisting of an electrical separator and electronic circuit. The latter controls the separator closure and opening. The results of measurements of the resistance between the columns indicate the possibility of implementing a communication channel.

Design Simulation and Test of Nano Electro Mechanical Switch Based on On-Line Test through Bias super position

In this paper, Nano Electromechanical Switch (NEMS) was designed and simulated by using MATLAB simulation, then was tested by on-line test through bias super-position. This switch has 4.5 nm thickness, offers low power dissipation and permits nonstop observing of all essential jobs. On the other hand, there are some challenges facing this Nano system. One of them is very difficult to resonators collective products with the same characteristics. The fabrication process was also a complex process and much hardness occurred during repetitive operations, which failure and stiction caused problems.
 In this work, a comparison between the response of a fault-free system and the system with some failures has been carried out. The test results showed a decrease in pull-in voltage with increasing overlap area as a result of wear failure mechanism in Nano Switch (NS). Creep in (NS) affected the value of the young modules and this increased the output voltage, also the crack in the beam of (NS) increased the effective mass and decreased output signal.

Understanding the wear failure mechanism of TiAlSiCN nanocomposite coating at evaluated temperatures

The work investigated the tribological behavior of TiAlSiCN coating at evaluated temperatures. Results showed that TiAlSiCN coating exhibited excellent wear resistance at room temperatures due to the formation of diamond-like carbon (DLC), but suffered aggravated oxidation damage and graphitization of DLC with the increased service temperature. The graphitized DLC severely weakened the toughness of the coating texture, resulting in degraded wear resistance, while the severe oxidation erosion seriously weakened the lubrication efficacy and wear resistance of the top oxide composite layer. The significant synergistic damage effect of oxidation-graphitization eventually resulted in the deteriorated anti-wear performance of this coating. These current findings provide insights into the wear failure mechanism of DLC doped coating at evaluated temperatures.

Microstructure Evolution and Mechanical Behavior of Mo–Si–N Films

The molybdenum silicon nitride (Mo–Si–N) films were deposited by a radio frequency (RF) magnetron reactive dual-gun co-sputtering technique with process control on input power and gas ratio. Composition variation, microstructure evolution, and related mechanical and tribological behavior of the Mo–Si–N coatings were investigated. The N2/(Ar + N2) flow ratios were controlled at 10/20 and 5/20 levels with the tuning of input power on the Si target at 0, 100, and 150 W. As the silicon contents increased from 0 to 33.7 at.%, the film microstructure evolved from a crystalline structure with Mo2N and MoN phases to an amorphous feature with the Si3N4 phase. The analysis of selected area electron diffraction patterns in TEM also indicated an amorphous feature of the Mo–Si–N films when Si content reached 20 at.% and beyond. The hardness and Young’s modulus changed from 16.5 to 26.9 and 208 to 273 GPa according to their microstructure features. The highest hardness and modulus were attributed to nanocrystalline Mo2N and MoN with Si solid-solution. The crystalline Mo–Si–N films showed a smooth tribological track and less wear failure was found. In contrast, the wear track with severe failures were observed for Mo–N and amorphous Mo–Si–N coatings due to their lower hardness. The ratios of H/E and H3/E2 were intensively discussed and correlated to the wear behavior of the Mo–Si–N coatings.

Effect of slippage rate on frictional wear behaviors of high-speed steel with dual-scale tungsten carbides (M6C) under high-pressure sliding-rolling condition

The article studies on the effect of slippage rate on frictional wear behaviors of high-tungsten high-speed steel (HTHSS) under high-pressure contact by using a self-made ring-on-ring wear machine. The microstructure of HTHSS is characterized by dual-scale tungsten carbides, including microscale eutectic M6C carbide [(Fe0.55W0.30Cr0.08Mo0.07)6C] and nanoscale secondary M6C carbide. Slippage rate has a significant effect on frictional wear behaviors. The peak value of friction coefficient occurs at the slippage rate of 5.5%. The friction coefficient will reduce whether the slippage rate increases or decreases. However, the increase in slippage rate makes wear failure mechanism change from fatigue to scratch, causing continuously significant increase in wear weight loss. The roles of different scale M6C carbides in resisting wear were also discussed.

Study on Wear Properties of J11 Wheel Steel with Nonuniform Microstructure

In actual wheel–rail systems, a nonuniform microstructure of the wheel and rail materials is a serious problem. A double-disk rolling wear test device was used to study the influence of the nonuniform microstructure on the wear properties of wheel materials in the present study. The results show that the microstructure of the sample 1 includes proeutectoid ferrite, pearlite, and upper bainite, which is a nonuniform microstructure. By contrast, the microstructure of sample 2 contains only proeutectoid ferrite and pearlite. During wear tests, with the increasing number of test cycles, the weight loss of the sample 1 is consistently larger than that of the sample 2. A similar trend is observed with respect to deformation of the plastic layer. For the sample 1, fatigue cracks mainly propagate along the interface between the upper bainite and pearlite, leading to rapid wear failure; the main wear mechanism changes from spalling to fatigue with the increasing number of cycles. For the sample 2, the main wear mechanism changes from adhesive wear to fatigue wear with increasing number of cycles.

Wear characteristics of nanoporous alumina and copper filled nanocomposite coatings

Anodisation of pure aluminium under certain conditions, form nanoporous alumina (NPA) with highly ordered pores. High interface strength and hardness make NPA an ideal tribological coating. The nanopores can be filled with metals using electrodeposition to give rise to a nanocomposite coating with better tribological properties. In this study, the friction and wear behaviour of NPA and copper filled nanocomposite coatings are studied under dry reciprocation conditions with a hard zirconia ball. The coefficient of friction of NPA and the nanocomposite is found to be about 0.95. Wear particles are generated by the propagation of surface microcracks and possibly by compaction. From the SEM images of the wear tracks, it is found that these wear particles form a protective tribolayer. The wear process of the coatings is characterised by three distinct regimes of constant wear rate, low wear, and catastrophic failure. The coating fails, possibly by radial cracking, when the thickness of the unworn coating reaches a critical value. Uniform filling of copper in the nanopores is found to enhance the wear life.

Study on vibration mechanism induced by skidding in pure rolling contact

Skidding in a rolling bearing often causes unexpected surface wear and uneven vibration. To explore the fundamental interaction mechanisms, an investigation is conducted experimentally and numerically on the tribo-dynamic responses of a simplified sliding-rolling contact. Vibration analyses show that the tangential vibration contains not only the rotational frequency of the roller but also the higher harmonics excited by the sliding-rolling contact. Surface contact stress analysis is also carried out with a twin-discs model. Results show that, with sliding occurring in the rolling contact, the unstable shear stress variation is induced and becomes the root cause of the tangential vibration. Further wear checks reveal that the wear failure under sliding-rolling contact coincides with the shear effect of contact interfaces.

Tribological properties of carbon reinforced and silica reinforced FKM against AISI 304 L

Fluoroelastomers (FKM) are used as a wheel material for in-service inspection, ISI vehicle as well as in leak resistance barriers in rotating plugs in sodium-cooled, pool type, 500 MV(e), Prototype fast Breeder reactor, PFBR. The wheel lining material is vulnerable to sliding wear failure due to the adverse operating conditions. The FKM rubber is reinforced by carbon and silica to enhance the sliding wear resistance. Dry sliding wear characteristics of Fluoroelastomers are studied at varying load condition and sliding speed by Pin on Disc experiment against an austenitic stainless steel AISI 304 L disc as a counter body. Sliding wear plots are recorded and correlated with various wear parameters. It was found that the carbon-reinforced FKM shows greater wear resistance and better frictional characteristics compared to silica-reinforced FKM on dry sliding wear tests. The outcome of this research will be significant in the development of FKM wheel lining of ISI vehicle of the PFBR in friction as well as wear perspective.

A method to calculate the life of sliding bearings based on fatigue and wear failure considering fluid lubrication

In this paper, a sliding bearing is taken as the research object to study the life simulation and calculation under conditions of a certain eccentricity, a radius clearance, inlet and outlet pressures, a radial load, and taking into account fatigue and wear failure modes. For a calculation case when the eccentricity is 0.6, the average radius gap is 0.05 mm, the inlet pressure is 2 MPa, the outlet pressure is 0.1 MPa, and the radial load is 5000 N. The calculated fatigue life is infinite and the wear life is 7.1×104 revolutions. This paper focuses on providing a method for quantitatively estimating the life of sliding bearings.

Structure-property relationship of glass fabric/MWCNT/epoxy multi-layered laminates

Neat glass fabric/epoxy composites (GECs) and multi-wall carbon nanotube/glass fabric/epoxy composites (MWCNTGECs) were prepared by hand-lay-up followed by compression molding technique and investigated the structural properties. It is found that the mechanical properties and wear resistance of the glass fabric reinforced epoxy composite improved upon the addition of MWCNTs. The 0.3 wt%MWCNTs filled glass fabric/epoxy composite (0.3MWCNTGECs) exhibits better properties as compared to 0.075 wt% MWCNT filled glass fabric/epoxy composites (0.075MWCNTCs), 0.15 wt% MWCNT filled glass fabric/epoxy composites (0.15MWCNTCs) and GECs. The mechanism of wear failure of these composites was analyzed from the morphology of worn surfaces. It was observed solid lubricant film established on the wear track at higher normal loads reduces the wear. The correlation of Vickers's hardness and Lancaster factor (σe)−1 with specific wear rate is investigated and reported.