Mechanism-based wear debris classification (WDC) is important for root cause analysis and prediction of wear related faults. Compared to manual classifications, automatic WDC is more efficient and ...often more reliable for a wide range of industrial applications. However, existing methods unavoidably encounter some difficulties when dealing with those wear particles with highly geometric similarity, especially for fatigue particles and severe sliding particles. To meet the requirement for automatic WDC, an integrated, automated method for identifying typical wear debris is proposed with a two-level classification procedure. By referring to the traditional ferrography – a widely used wear particle imaging and analysis technique, the first-level classification is performed by a general back-propagation (BP) neural network with selected particle's morphological features. By doing this, three types of wear particles including rubbing, cutting, and spherical particles can be determined. In the second-level classification, a deep learning model of a 6-layer convolution neural network (CNN) is adopted to identify fatigue particles and severe sliding particles by analyzing their very slight surface details in pixel-level. The method is tested with over 100 images of real particles generated from an extruder machine in a petrochemical plant and identified by a ferrograph specialist. A high recognition rate of over 80% is achieved for the three types including rubbing, cutting, and spherical particles with the first procedure. Further, the identification rates are 85.7% and 80% for fatigue particles and severe sliding particles, respectively, which is distinctly improved from the reported values (they are 45.5% and 36.4%, respectively) of other intelligent methods.
•Four typical groups of wear particles are characterized using numerical parameters.•A BP neural network is adopted to identify rubbing, cutting, and spherical particles.•Fatigue and serious sliding wear particles were identified by a 6-layer CNN.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The aim of this work is to map the wear debris concentration with wear rate. A wear debris attenuation function is proposed to depict quantitatively the removal of wear debris. The total residual ...mass of wear debris in lubrication systems can be stated as the convolution of the wear rate and the wear debris attenuation function. Additionally, the dynamic responses of the wear debris concentration under different wear rate excitations are also presented. To simulate and verify how the debris concentration changes, an oil lubrication system test rig is built, and on-line visual ferrograph (OLVF) is used to monitor the debris concentration. Two experimental results indicate that the variation of the wear debris concentration is consistent with the model result.
•A mathematical model is developed to map wear debris concentration with wear rate.•A wear debris attenuation function is proposed to depict the wear debris removal.•The dynamic responses of wear debris concentration are presented.•The study provides a new approach to explain the on-line wear debris concentration.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Fe-doped zirconia toughened alumina (Fe: ZTA) ceramic is a promising material for artificial joint implants because of high density, good mechanical properties and excellent wear resistance. To ...evaluate its use in biological implants, Fe: ZTA ceramics with different Fe contents (0–5 wt.%) were fabricated using the fast hot pressed sintering method, and the biocompatibility of Fe: ZTA ceramics and the biotoxicity of wear debris from Fe: ZTA were systematically studied. The additive Fe element mainly exists in the form of FeAl2O4. The addition of Fe results in the increase of surface hydrophobicity and the decrease of surface energy and polar component, improving the protein absorption on Fe: ZTA surface. According to the culture results with osteoblasts and macrophages, Fe doping can increase the osteoblast activity and does not cause significant macrophage activation on the surface of Fe: ZTA ceramics. Particularly, the 1.5 wt.% Fe: ZTA ceramic can significantly improve the cytocompatibility of osteoblasts and reduce the inflammatory reaction. On this basis, 1.5 wt.% Fe: ZTA ceramic with the best biocompatibility was used to prepare the wear debris, and the biotoxicity of wear debris was further studied. The result confirms that wear debris of Fe: ZTA ceramic (50–1000 μg/ml) does not cause the significant decrease in osteoblast activity and has no significant effect on the osteoblast morphology, without distinct cytotoxicity. The wear debris of Fe: ZTA (≤ 200 μg/ml) will not cause significant inflammatory response. This study can provide guidance for the application of Fe: ZTA ceramic in biological implants.
•Fe doping improves the protein adsorption on ZTA surface.•ZTA ceramics with Fe contents (0–5 wt.%) have good cell compatibility.•1.5 wt% Fe: ZTA can improve osteoblasts cytocompatibility and reduce inflammatory reaction.•Wear debris of Fe: ZTA (50–200 μ g/mL) has no cytotoxicity and doesn't cause inflammation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A high throughput wear debris sensor consisting of 3×3 sensing channels is presented for real time online lubricant oil conditioning monitoring. Time division multiplexing was applied to the sensing ...channels for measuring responses of multiple channels using one set of measurement electronics. Crosstalk among the 3×3 sensing channels was eliminated by diodes that are connected in series with each channel. Parallel L-C-R resonance was also applied to each sensing coil to increase the sensitivity. Furthermore, a unique synchronized sampling method was used to reduce the date size 50 times. Finally, we demonstrated that the sensor is capable of real time detection of wear debris as small as 50µm in SAE 0W-5 at a flow rate of 460ml/min; the measured debris concentration is in good agreement with the estimated actual concentration. The design can be extended to a N×N sensor array for an extremely high throughput without sacrificing the sensitivity, and can potentially be used for real time wear debris monitoring for health condition of rotating or reciprocating machineries.
•The wear debris sensor array enables a high throughput (i.e., 4.1 L/min).•Time division multiplexing combined with series diodes removes the crosstalk effect.•Synchronized sampling significantly reduces the data size and data processing time.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Lubrication is one of the critical factors for the normal operation of wind turbine's gearbox, which carries abundant and various wear debris. Accordingly, these debris reflects the running state of ...the equipment and forecasts the early fault of wind turbine gearbox effectively. Thus, the authors can achieve predictive maintenance, even avoid the occurrence of safety accidents. In order to realise real-time online monitoring of lubrication, this article studied the principle of wear debris detection sensor, constructed approximate mathematical model of inductive wearing debris sensor, produced a prototype device, and carried out the monitoring test of metal wearing debris without oil. Experiment shown that the designed sensor can detect the signal of metal wear debris with the smallest diameter to 80μm, which can diagnose the early fault of the wind turbine.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Mechanical debris is an important product of friction wear, which is also a crucial approach to know the running status of a machine. Many studies have been conducted on mechanical debris in related ...fields such as tribology, instrument, and diagnosis. This paper presents a comprehensive review of these studies, which summarizes wear mechanisms (e.g., abrasive wear, fatigue wear, and adhesive wear) and debris features (e.g., concentration (number), size, morphology, and composition), analyzes detection methods principles (e.g., offline: spectrograph and ferrograph, and online: optical method, inductive method, resistive-capacitive method, and acoustic method), reviews developments of online inductive methods, and investigates the progress of debris-based diagnosis. Finally, several notable problems are discussed for further studies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The dry sliding wear behavior of Al 5252 alloy and its composites reinforced with nanometric or micrometric SiC particles is studied. The wear tests were conducted on hot extruded samples using a pin ...on the disc configuration under normal stresses: 0.3, 0.6 and 0.9MPa at a sliding speed of 0.5m/s and distance of 1000m. The dominant wear mechanisms were determined using microstructural characterization, hardness measurement, EDS analysis as well as microscopic studies of wear surfaces and debris. The composite reinforced with micrometric SiC particles showed the lowest wear rate at the applied stresses of 0.3 and 0.6MPa, while the nano-composites exhibited the best wear resistance at the normal stress of 0.9MPa.
•SiC nano-particles were uniformly distributed within Al 5252 matrix using IPM method.•Micrometric SiC reinforced composites showed lower wear rates at low normal loads.•Nano-composites exhibited the best wear resistance at high normal loads.•Delamination was the dominant wear mechanism at high loads for the micro-composite.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Road transportation significantly contributes to environmental pollution, both in terms of exhaust and non-exhaust (brake wear) emissions. As was proven, brake wear debris is released in a wide ...variety of sizes, shapes, and compositions. Although studies confirming the possible adverse health and environmental impact of brake wear debris were published, there is no standardized methodology for their toxicity testing, and most studies focus only on one type of brake pad and/or one test. The lack of methodology is also related to the very small amount of material released during the laboratory testing. For these reasons, this study deals with the mixture of airborne brake wear debris from several commonly used low-metallic brake pads collected following the dynamometer testing. The mixture was chosen for better simulation of the actual state in the environment and to collect a sufficient amount of particles for thorough characterization (SEM, XRPD, XRF, chromatography, and particle size distribution) and phytotoxicity testing. The particle size distribution measurement revealed a wide range of particle sizes from nanometers to hundreds of nanometers, elemental and phase analysis determined the standard elements and compounds used in the brake pad formulation. The Hordeum vulgare and Sinapis alba were chosen as representatives of monocotyledonous and dicotyledonous plants. The germination was not significantly affected by the suspension of brake wear debris; however, the root elongation was negatively influenced in both cases. Sinapis alba (IC50 = 23.13 g L-1) was more affected than Hordeum vulgare (IC50 was not found in the studied concentration range) the growth of which was even slightly stimulated in the lowest concentrations of brake wear debris. The plant biomass was also negatively affected in the case of Sinapis alba, where the IC50 values of wet and dry roots were determined to be 44.83 g L-1 and 86.86 g L-1, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The progress of oil debris monitoring technologies of rotating machinery over the past 30 years is reviewed.•Sensors are classified into magnetic, electrical, optical, and acoustic methods.•The ...sensing principles, structures, and characteristics (advantages and disadvantages) of wear debris sensors are covered.•A comparison of current oil debris sensing technologies is conducted.•Future trends and challenges are discussed.
Oil debris monitoring has played an irreplaceable role in ascertaining the health condition of rotating machinery (e.g. engine, gearbox). Although many sensing methods for detecting wear-generated particles of rotating elements have been presented, a comprehensive review paper on these technologies is still missing. To this end, this paper provides a detailed survey of the advances in oil debris monitoring for the online health monitoring of rotating machinery. According to the detection mechanism, these sensing technologies are classified under varying categories (magnetic: magnetic chip detectors and inductive sensors, electrical: resistive-capacitive sensors and electrostatic sensors, optical: photoelectric sensors and imaging sensors, acoustic). The systematic analysis and commentary on each sensing method are conducted, and real applications also be reviewed. These sensing technologies are not confined to research-related activities, of which some have already been patented and commercialized. Finally, future works are presented to meet the challenges faced by online monitoring of rotating machinery.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
To address the influence of wear debris on friction-induced stick-slip vibration (FISSV), a method involving grooving the friction disc was proposed. FISSV simulation experiments were conducted using ...a test setup. A finite element model (FEM) was established for dynamic simulations. The results show that wear debris significantly influences FISSV. Debris involved in friction will result in significant abrasive wear. Extensive debris entering the interface causes the worn surface to have numerous small contact plateaus with lower contact stiffness, leading to pronounced FISSV. Conversely, the presence of larger contact plateaus on the worn surface increases contact stiffness, making the friction system less prone to generating FISSV. Filling groove with graphite effectively suppresses FISSV. Controlling debris flow is crucial for suppressing FISSV.
●A method of machining groove on friction surface to regulate wear debris behavior was proposed.●A friction-induced stick-slip vibration simulation test was carried out on a test rig.●Finite element simulation of friction-induced stick-slip vibration considering block wear was carried out.●The effect of interfacial wear debris on the friction-induced stick-slip vibration was discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZRSKP
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