Wear Debris Detection Research Articles

Correction: A Comparative Study of Wear Debris and Vibration-Based Gear Damage Detection Methods Applied to Mild Wear in a Spur Gear System

Correction: A Comparative Study of Wear Debris and Vibration-Based Gear Damage Detection Methods Applied to Mild Wear in a Spur Gear System

A Comparative Study of Wear Debris and Vibration-Based Gear Damage Detection Methods Applied to Mild Wear in a Spur Gear System

A Comparative Study of Wear Debris and Vibration-Based Gear Damage Detection Methods Applied to Mild Wear in a Spur Gear System

Oil wear debris sensor with temperature compensation

In this paper, in response to the problem that oil temperature changes will affect the detection results of the inductive wear debris sensor, a Wheatstone bridge-type oil wear debris sensor was designed using two two-wire helical tube coils, precision potentiometers, precision resistors, and a conditioning circuit with differential, phase-locked, and amplification functions were designed. Through practical tests, 72–400 μm iron particles were detected under the water bath's heating condition from 20℃ to 70℃. It proves that the designed Wheatstone bridge sensor and conditioning circuit can detect ferromagnetic particles in multiple temperature oil. The de-signed sensor and conditioning circuit effectively solves the problem of temperature drift of the detected signal under high-temperature conditions, improving the signal-to-noise ratio of wear debris detection under multiple temperatures. The sensor is suitable for lubricant detection systems with varying or constant high oil temperatures. The work presented in this paper provides significant reference value for the practical operation of oil sensors in real-world environments.

A panoramic ferrograph for on-site detection of oil wear debris

For the on-site visual detection of oil wear debris, a panoramic ferrograph was proposed. A rotation-symmetric high-gradient permanent magnetic field was constructed to deposit wear debris without a pump and valve. And a template-based stitching image algorithm was used to generate panoramic debris images. Moreover, the index of particle coverage area (IPCA) of 12 panoramic debris images was statistically analyzed. The coefficient of variation (CV) of IPCA is 6.1%, which indicates a high repeatability. In particular, the detector can also image debris in black oil. The panoramic ferrograph has the advantages of no need for a pump and valve, no oil sample consumption, and a high repeatability, which can provide a new means for the rapid on-site oil debris analysis.

A wear debris recognition method based on dual-channel electrostatic signal and prominence of cross-correlation function

Electrostatic monitoring is a hot technique used for online wear debris detection. This study presented a recognition method by using a dual-channel electrostatic senor. A signal enhancement model based on an improved Variational Mode Decomposition (VMD) by double screening intrinsic mode function was proposed. Wear debris recognition algorithm and its processes were researched by using the dual-channel signals and the prominence of cross-correlation value. Experiments were conducted on a gear reducer bench, and the results of wear debris recognition between the electrostatic sensor and the inductive sensor were compared. The results show that the suggested algorithm can efficiently recognize signal pulses caused by wear debris, offering an effective analytical approach for early identification of wear status.

Motion simulation analysis of wear debris in an integrated detection unit for lubricating oil

Accurate wear debris detection is vital for diagnosing engine wear. However, due to uncertainties in debris behavior, size, and operating conditions, identifying different materials with a single sensor is challenging. To improve sensitivity and accuracy, we propose an integrated detection unit for wear debris in lubricating oil, emphasizing multifunction integration and active intervention. This unit includes a static mixer, a flared transition zone, and a sensor-equipped detection zone. Parametric analysis reveals that debris mixed in the static mixer tends to aggregate toward the center, forming three distinct distribution rings at the detection unit's outlet. A 90° blade angle and a 1:1 aspect ratio enhance the difference in debris quantity between inner and outer rings. To enhance detection reliability, installing capacitive sensors at the front and electromagnetic sensors at the rear of the detection zone can improve the accuracy of detecting different materials debris. This concept offers a multifunctional solution for precise wear debris detection, addressing complex wear scenarios in engines.

Application of a Wear Debris Detection System to Investigate Wear Phenomena during Running-In of a Gasoline Engine

When a tribological system is operated for the first time, the first hours of operation are of the utmost importance as the surfaces of the contacting elements mate to each other, involving significant wear processes until the surfaces reach stable topological characteristics. This initial phase in a combustion engine is known as running-in and is of critical importance in the study of friction and wear phenomena. Despite this, there is little information in the literature dedicated to running-in and, therefore, data improving its understanding is greatly anticipated. In this work, a novel wear debris detection system measuring in real time was employed to investigate the running-in of an inline 4-cylinder gasoline engine; it consists primarily of an optical sensor with the capability of detecting very small particles from 4 μm. For the tests, the engine was mounted on a test bench and operated under stationary working conditions. The results of the wear debris measurements showed interesting insights into the engine running-in process; although in general, the results followed the expected trend, they also showed an unexpected behavior: it was expected to obtain the highest amounts of wear debris at the beginning of the running-in, but instead the number of debris stagnated and only started to increase after about 20 h to then decrease again. The best operating conditions to run-in the engine were identified at the middle of the running-in period, without the presence of large wear debris that could lead to severe wear. Finally, it was found that the engine running-in was not finished until at least 75 h of operation, although commonly, a running-in time of 10 h is used in the industry.

An Asymmetric Micro-Three-Coil Sensor Enabling Non-Ferrous Metals Distinguishment

At present, when performing material identification of metal wear debris, most sensors can only roughly distinguish between ferromagnetic and non- ferromagnetic metal wear debris, but fail to distinguish them deeply. To achieve fine detection of metal wear debris in the oil, this paper designs an asymmetric micro-three-coil sensor, which generates an asymmetric magnetic field by using two excitation coils of different sizes. Different metal wear debris are affected differently in the magnetic field and the shape of the output signal is also different, therefore, the wear debris material can be distinguished by the shape of the signal of the induction electric potential output from the induction coil alone, and the wear debris size can be determined by the amplitude of the signal. Copper particles, aluminum particles, iron particles and 304 stainless steel particles were selected as experimental objects, and the experimental results showed that the material differentiation of these four types of particles can be achieved by the asymmetric magnetic field of the sensor. The method provides a new research direction for the inductive method to distinguish non-ferrous metals, which is important for the fine detection of multi-parameter pollutants and the diagnosis and monitoring of mechanical system faults.

A Permanent Magnet Ferromagnetic Wear Debris Sensor Based on Axisymmetric High-Gradient Magnetic Field.

The detection of wear debris in lubricating oil is effective for determining current equipment operating conditions for fault diagnosis. In this paper, a permanent magnet ferromagnetic wear debris sensor is proposed that is composed of a compact structure and a detection coil that generates an induced voltage when wear debris passes through a magnetic field. A three-dimensional model of the sensor is established, the internal axisymmetric high-gradient magnetic field of the sensor is analyzed, and a mathematical model of the sensor signal is proposed. The effects of the air gap structure of the sensor and the relative permeability, velocity, and volume of the wear debris on the sensor performance are analyzed. The correctness of the theoretical results is proven by single particle experiments, and the sensor is calibrated to achieve quantitative analysis of the wear debris.

The Optimization of Parallel Resonance Circuit for Wear Debris Detection by Adjusting Capacitance

Wear debris in lubrication oil provides important information for marine engine condition monitoring and faults diagnosis. Inductive sensors have been widely used to detect wear debris in lubrication oil. To improve the sensitivity, the inductive coil is always connected with a capacitor in parallel to form parallel LC resonance-sensing circuit. A previous study optimized the parallel resonance circuit by adjusting the excitation frequency. However, multiple parameters (namely, excitation signal, signal detection circuits, and signal-processing program, etc.) need to be adjusted accordingly for a series of the testing frequencies. To simplify the optimization, we propose a method based on adjusting the parallel capacitance in this work. The impedance (inductance and internal resistance) of the sensing coil and its variation induced by particles are first measured, which are the necessary parameters for establishing the function relationship between the parallel capacitance and the relative impedance variation. With the function relationship, the relative impedance variation is calculated directly, and the optimal capacitance is located at the highest absolute value of it. The experimental results for the ferrous and nonferrous particles match the calculation results well. Interestingly, the optimal capacitance for the nonferrous particle was larger than that of the ferrous particle. We speculate that the difference is generated due to the increased resistance induced by the eddy current effect.

Research on the Influence of Coil LC Parallel Resonance on Detection Effect of Inductive Wear Debris Sensor.

The coil structure of the inductive wear debris sensor plays a significant role in the effect of wear debris detection. According to the characteristics of LC parallel resonance, the capacitor and coil are connected in parallel to make sensor coils in the LC parallel resonance state, which is beneficial to improve the ability to detect wear particles. In this paper, the mathematical model of output-induced electromotance of the detection coil is established to analyze the influence of the structure on the detection sensitivity and enhance the sensor’s current rate of change to the disturbance magnetic field, which is essential to resist noise interference. Based on the coherent demodulation principle, the AD630 lock-in amplifier is applied to the test platform to amplify and identify weak signals. In addition, experiments are designed to test the output signals of debris under the condition of different original output voltages of the sensor with a parallel structure. Meanwhile, the near-resonance state of the detection coil with LC parallel circuit is tested by output signal information. Results show that the sensor detection sensitivity will be effectively improved with the LC parallel coil structure. For the sensor structure parameters designed in this paper, the optimal raw output amplification voltage for abrasive particle detection is 4.49 V. The detection performance of ferromagnetic particles and non-ferromagnetic particles is tested under this condition, realizing the detection ability of 103.33 μm ferromagnetic abrasive particles and 320.74 μm non-ferromagnetic abrasive particles.

Performance and Wear Debris Characteristics of Karanja Biodiesel and Biolubricant as a Substitute in a Compression Ignition Engine

A dependency on non-renewable petroleum fuel and lubricant in Compression Ignition (CI) engines is concerning when considered with respect to both price and pollution. Alternative energy for CI engines extracted from plants is reliable, renewable, and infinitely more sustainable than fossil fuels. The CI engine's performance and wear analysis is carried out with biodiesel and biolubricant through Condition Based Monitoring (CBM). Biodegradable plant-derived biodiesel extracted from non-edible Karanja seed oil is used as a substitute in assessing the engine's combustion, performance and wear characteristics. An initial benchmark was established for the engine's performance with diesel and engine oil (SAE20W40), after which it was subjected to a long-term endurance test when fuelled with biodiesel blend 20BD as fuel under biolubricant blend 20BL as a lubricant. Lubricating oil samples are collected after 50, 75, 100, 125, and 150 hrs. Finally, the used oil analysis was conducted to analyse the wear debris of oil samples using Atomic Absorption Spectroscopy (AAS) technique. Results revealed lower wear debris detection in the case of biodiesel and biolubricant combination due to better lubricity of plant-derived oil than that of petroleum-derived oils. Finally, the Karanja biodiesel and biolubricant can be used as a substitute in CI engines without requiring engine alteration.

Electrokinetic transportation and differentiation of copper and aluminum particles in oil with an oil-water interface

The transportation of metal particles in oil has numerous applications in industrial areas. Under electric field, the electroosmotic flow of the oil-water interface can be generated; therefore, the electrokinetic transportation of the metal particles is expected by attaching the metal particles from the oil phase into the oil-water interface. In this paper, an oil sample containing metal particles was placed onto an aqueous electrolyte solution and let the metal particles settle at the oil-water interface by gravity sedimentation. The contact angles of the metal particles at the oil-water interface were measured first. Subsequently, the electrokinetic transportation of metal particle was investigated by applying a direct electric field along the oil-water interface. The experimental results indicate that at the interface, the metal particle immersed totally in the oil phase. The electrokinetic motions of the metal particles can be generated in the direction opposite to the applied electric field. The velocity of the particle is independent of particle’s diameter, increases with the decrease in particle’s mass density and with the increase of the applied electric field. Aluminum and copper particle differentiation was achieved by using a so-called specific sized-velocity. This transportation method demonstrated in this paper opens opportunities in electrical manipulation of metal particles in oil for the fields of mechanical wear debris detection.

High-Sensitivity Large-Throughput Broadband Tunable Microwave Wear Debris Sensing System

A highly sensitive, large throughput and wide dynamic range (in the aspect of size and material type) broadband tunable microwave interferometer based rectangular waveguide wear debris detection system is presented. Passing of (non)ferrous and (non)conductive particles through the sensor, which causes inductance and/or capacitance changes, are detected as transmission signal variations of the system. We first demonstrate the sensing principle with the aluminum particle of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$800~\mu \text{m}$ </tex-math></inline-formula> and epoxy resin particle of 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> at 6 GHz. Then, the effects of particle size and flow speed are tested with aluminum particles ranging from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$200~\mu \text{m}$ </tex-math></inline-formula> to 1.8 mm. The measurement results show that the system is able to measure particle sizes with known material and differentiate nonconductive particles from conductive ones. With the proposed data processing techniques, this system is capable of detecting as small as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$76~\mu \text{m}$ </tex-math></inline-formula> particles within an 8 mm outer diameter tube. And with future improvements on sensitivity and particle material characterization, the proposed system has the potential to differentiate (non)ferrous and (non)conductive particles and measure their sizes as a real-time wear debris sensing devices for rotating and reciprocating machines.

A Novel Multichannel Inductive Wear Debris Sensor Based on Time Division Multiplexing

Inductive wear debris sensor has been proved to be an effective device for lubricant oil condition monitoring and fault diagnosis. However, the narrow internal diameter of current sensing coil, designed for high sensitivity, limits the oil throughput. To improve the throughput without sacrificing the sensitivity, a novel multichannel wear debris detection method based on time division multiplexing is presented in this work. Only one excitation signal is used to excite multiple sensing coils. Then, the signals from multiple sensing coils are combined with a serials of square waves separately, which are self-designed specially. As a result, the peak waveforms are lifted in different timeslots by the high-level voltages in squares waves. After that, the peaks of the signals are cut out and combined into one output signal. Then, we used synchronized sampling method to record the peak values of the output signal. The signals for all sensing channels are finally extracted from the recorded peak values. To validate the feasibility of the proposed method, we designed a ten-channel sensor system using time division multiplexing. Through the pseudo-dynamic and dynamic test, it is proved that the sensor could detect wear debris in different channels simultaneously and independently without sacrificing the sensitivity. In addition, the proposed method has the potential to integrate more channels into one system, which would contribute to high throughput real time lubricant oil detection.

A Highly Sensitive In-Line Oil Wear Debris Sensor Based on Passive Wireless LC Sensing

This paper presents ${a}$ new, and efficient, wear debris detection sensor based on passive wireless LC sensing approach. This sensor enables online monitoring of metal debris in hydraulic flow tubes with large thickness, employed in high-pressure applications. In conventional inductive debris sensors, the coil is kept outside the tube. $(i)$ Hence, for thick tubes, the sensitivity is extremely low. If the coil is kept inside the tube, holes are required to connect it to the measurement unit (MU). (ii) This limits the pressure withstanding capacity. The proposed sensor solves these two problems using the wireless LC sensor approach, wherein the MU is connected to an outer coil (outside the thick tube), and an inner coil is kept close to the oil, with debris. Thus, it is highly sensitive to the debris. It requires no electrical connection to the MU. The outer coil is energized from an AC signal at the parallel resonance frequency of the system, drawing minimum current from the source. The change in phase of this current, due to the change in inductance of the inner coil as debris passes, is measured using ${a}$ phase-sensitive detector. This highly sensitive measurement approach together with the fact that the inner coil is close to the oil, helps to achieve high sensitivity, and enables monitoring flow tubes with large diameter and thickness. ${A}$ prototype of the proposed wireless LC debris sensor has been developed (inner and outer diameters of 25.4 mm and 80 mm respectively), integrated into ${a}$ hydraulic circuit and tested. The output was not only very sensitive to ferrous and non-ferrous metallic particles but also helps in distinguishing them.

An Integrated Inductive-Capacitive Microfluidic Sensor for Detection of Wear Debris in Hydraulic Oil

A lot of important information about the working state of hydraulic components can be reflected by wear debris in hydraulic oil, the detection of debris can prevent hydraulic system failures. Due to the weak ability of inductive pulse sensor to detect non-ferromagnetic metal particles, an integrated wear debris sensor, which includes a capacitive pulse sensor and an inductive pulse sensor, is proposed in this paper. The frequency characteristics of the capacitive sensor were explored through experiments, and optimal detection frequency is 0.5MHz. Capacitive sensor can detect and distinguish between air bubbles and metal debris. Inductive sensor can detect and distinguish ferromagnetic and non-ferromagnetic metal debris. By comparing and analyzing the results of two sensors, the integrated sensor with $300~\mu \text{m}$ channel can detect air bubbles larger than $80~\mu \text{m}$ , 30–300 $\mu \text{m}$ iron particles and 45–300 $\mu \text{m}$ copper particles, and effectively distinguish the properties of particles.

Study on online monitoring wear debris sensor of wind turbine gearbox

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.

The Effects of Position on the Wear Debris Detection with Planar Inductor.

Wear debris detection is an effective method to determine the running state of the machine. Recently, the planar inductor is commonly used to detect wear debris. The previous studies have found that the inductive signal would be varied while changing the position of wear debris pass through. However, the effect of position on the wear debris detection is not well understood. In this paper, a novel detection system in which the position of wear debris pass through could be adjusted precisely is designed. By changing the position in horizontal or vertical direction, the inductive signals of the wear debris were acquired. In the horizontal direction, the experimental results show that the amplitude of the inductive signal first increases and then decreases when the position changes from the center of the planar inductor to the outer. The maximum inductive signal appears when the wear debris pass through the edge of the inner coil, which is 20% higher than that for the center and much higher than that for the edge of outer coil. In the vertical direction, the signal decreases almost linearly when the position is away from the planar inductor. For every 0.1 mm step far away the planar inductor, the signal amplitude drops by approximately 10%. The variation trend of our experimental results is consistent with the numerical simulation results of magnetic intensity around the planar inductor.

Improving Sensitivity of a Micro Inductive Sensor for Wear Debris Detection with Magnetic Powder Surrounded.

The inductive detection of wear debris in lubrication oil is an effective method to monitor the machine status. As the wear debris is usually micro scale, a micro inductive sensor is always used to detect them in research papers or high-tech products. However, the improvement of detection sensitivity for micro inductive sensors is still a great challenge, especially for early wear debris of 20 μm or smaller diameter. This paper proposes a novel method to improve the detection sensitivity of a micro inductive sensor. Regarding the magnetic powder surrounding the sensor, the magnetic field in the core of the sensor where the wear debris pass through would be enhanced due to the increased relative permeability. Thus, the inductive signal would be improved and the detection sensitivity would be increased. It is found that the inductive signal would linearly increase with increasing the concentration of the magnetic powder and this enhancement would also be effective for wear debris of different sizes. In addition, the detection limit of the micro inductive sensor used in our experiment could be extended to 11 μm wear debris by the proposed method.