Browse Topic: Bearings

Items (3,348)
Find
A Study on the Tribological Behavior of Silicon Nitride-Based Multiphase Ceramics Under Different Lubrication Systems2026-99-2339To be published on 10/30/2026
To address the urgent need for high-performance self-lubricating ceramic materials for rolling bearings under high-speed operating conditions in the aerospace sector, this study employs Si3N4 as the matrix and incorporates nano lignin and graphene nanoplatelets (GNPs) to develop a self-lubricating composite ceramic system. This paper systematically studies the tribological characteristics and wear mechanisms of the composites. The results indicate that nano lignin undergoes pyrolysis during sintering, forming nitrogen-doped graphene quantum dots (N-GQDs). These structures are uniformly distributed at grain boundaries and participate in the formation of a lubricating film during the friction process, thereby significantly improving the material’s friction and wear properties. Under the special conditions (10 N, 1000 r/min), the composite material exhibited optimal tribological performance when the nano-lignin content was 2 wt.%, The friction coefficient decreased to 0.22 and a significant decrease in wear rate, demonstrating excellent friction- reducing and wear-resistant effects. In contrast, the introduction of GNPs failed to effectively improve friction performance, which may be attributed to their poor dispersion in the matrix and weak interfacial bonding. Mechanistic analysis indicates that during friction, Si N hydrolyzes to form SiO, which, together with the metal transfer layer and N-GQDs, forms a composite lubricating film; under shear stress, the N-GQDs undergo oriented alignment, reducing interfacial shear strength and achieving a synergistic effect of friction reduction and wear resistance. This study gives a new perspective into the application of biomass-derived lubricating phases in high- performance ceramics.
Chen, Wei, Zhao, Wenzhuo, Zhou, Ao, Li, Yetong, Wang, Chao, Yang, Yongqiang, Lou, Rui
Vibration–Acoustic Emission Fusion and STFT–MFDCNN for Fault Diagnosis of Bearings in the Aero-Engine2026-99-2315To be published on 10/30/2026
Rolling bearings are key components of aero-engine rotor systems, and their degradation can trigger abnormal dynamics and safety risks. Unplanned bearing failures increase downtime and inspection cost; early detection enables condition-based maintenance and reduces conservative replacement. Early faults are weak, intermittent, and often masked by operating variability, so diagnosis based on a single sensing modality is usually incomplete. Vibration signals describe global dynamic behavior and resonance responses, whereas acoustic emission (AE) captures micro-damage processes and short impulsive events. Given the differences in bandwidth and noise sources, combining vibration and AE can provide a fuller description of bearing states. This study proposes an STFT–MFDCNN framework for bearing fault diagnosis using fused vibration–AE information. First, synchronized vibration and AE signals are converted into time– frequency images via the short-time Fourier transform (STFT), preserving spectral content and temporal non-stationarity in a unified representation. Second, a dual-branch multi-scale feature dense convolutional neural network (MFDCNN) is constructed. In each branch, parallel convolutions with different kernel sizes capture fault patterns across receptive fields, and dense concatenation connects all preceding feature maps to improve feature reuse and gradient flow. Third, global average pooling generates compact feature vectors for both branches, which are concatenated in a fusion head and classified by a Softmax layer. Experiments on a vibration–AE dataset built in this work show that the proposed method reaches 97.78% identification accuracy. Compared with dual-branch fusion baselines based on AlexNet, ResNet, and a shallow CNN, accuracy increases by 3.34%, 4.45%, and 5.00%, respectively. Compared with single- modality models (Only-AE and Only-Vib), accuracy improves by 14.71% and 6.77%.
Li, Zhichuang, Wang, Xingfeng, Zhang, Yanpu, Yang, Guoan
Process and Performance Optimization Design of Metal-3D Braided Composite Joint Structures2026-99-2349To be published on 10/30/2026
The sleeve is the key assembly part of the high-speed internal electric spindle support of the high-precision CNC internal and external grinder, and its machining accuracy directly affects the running state of the spindle. The purpose of this study is to adjust the structural process to improve its bearing capacity in all directions. Combined with the refined mechanical simulation of 3D braided composites, the influence mechanism of joint thickness and surface pretreatment on the connection performance is studied from the aspects of stress distribution characteristics and damage failure mechanism. The overall performance analysis and design of the metal-composite sleeve are carried out. Experiments show that the thickness of the joint has a great influence on its bearing performance, and the effectiveness of the proposed pretreatment process is verified, which provides a reliable technical path for the realization of high-performance metal-3D braided composite connection structure.
Wang, Zijun, Chi, Xinfu, Li, Chengen, Li, Dinghua
A Multi-Platform Bearing-Only Localization Method Based on Confidence Interval and Error Compression Iteration2026-99-294610/19/2026
Due to the fact that passive underwater acoustic signals can usually only obtain the bearing information of the target and are subject to complex ocean environmental interference, which poses significant obstacles to target localization using a single platform, this study intends to employ multiple unmanned underwater vehicles for cooperative localization of underwater targets. To address the issues of systematic bias in bearing measurements, high nonlinearity, and unknown target motion states in complex underwater acoustic environments, this paper proposes a bearing-only localization method based on confidence interval and error compression iteration. The unknown motion process of the target is mapped into a region expansion process in space, and the cooperative localization of multiple platforms is used to finely compress the regional error, achieving bearing-only localization of underwater targets through gradual region compression. The core idea of the proposed method is to map the unknown motion state of the target into an expansion process of an uncertainty region. First, bearing-only measurements obtained by multiple platforms at different time instants are used to construct sector regions with systematic bias. Then, a likelihood function is employed to update the probability distribution over the spatial grid, enabling iterative error compression. Meanwhile, the 95% highest posterior density interval is introduced as the statistical output of the localization results. Simulation experiments were conducted under three different initial scenarios. The results show that, with bounded bearing measurement errors, the proposed method can compress the area of the 95% HPD region from approximately 107 m2 to the order of 104 m2 within 120 seconds, while the localization error converges from several kilometers to less than 40 meters.
Huang, Fengfeng, Wang, Yuxuan, She, Tao
Fault Diagnosis Study of MCSECNN Model Integrating MK-MMD and DANN under Variable Operating Conditions2026-99-297210/19/2026
Bearing signals measured under different loads rarely keep the same waveform characteristics. Their amplitudes, spectral components, and statistical properties may change at the same time, which makes a classifier trained on one load condition less reliable on another. This study investigates a cross-load diagnosis method that trains a multi-scale convolutional squeeze-excitation network (MCSECNN) with multi-kernel maximum mean discrepancy (MK-MMD) and a domain-adversarial neural network (DANN). The convolutional branch captures vibration patterns over several temporal ranges, and the SE unit adjusts the importance of the channels generated by the parallel kernels. MK-MMD penalizes the distance between load-dependent feature distributions, whereas DANN weakens the load identity retained in the features. Tests using CWRU bearing data show that the integrated model gives better accuracy than the basic MCSECNN and the two single-adaptation variants. Ablation results indicate that the statistical and adversarial constraints contribute to transfer performance in different ways.
Ming, Mei, Ai, Yumei, Li, Shengnan, Wan, Haozheng, Sang, Shentian, Zhang, Haifeng
Modeling and Analysis of Mechanical-Electrical Coupling in Flywheel Systems Considering Faults2026-99-292310/19/2026
Spacecraft flywheel systems are critical actuators for attitude control and stability maintenance, and their operating reliability is strongly affected by the health state of the supporting bearings. When local defects occur on the bearing raceway or rolling elements, the rolling contact state changes abruptly, which leads to time varying contact deformation, fluctuating support reaction force, and additional rotational resistance. Unlike many ground based rotating machines, spacecraft flywheel systems usually operate in compact and highly integrated configurations, where direct vibration measurement is difficult in practice. In contrast, motor current, voltage, and speed signals are easier to acquire and are therefore more suitable for condition monitoring. To describe how bearing defects propagate from the mechanical domain to electrical responses, a simplified electromechanical coupling model is developed for a flywheel rotor motor system with local bearing defects. First, a rolling element contact model is established using the defect induced deformation relation and Hertzian contact theory to derive the time varying bearing support force. Second, the fluctuating support force is mapped to an equivalent time varying load torque to represent the dominant pathway through which bearing defects influence the motor side. Third, the derived load torque disturbance is coupled with the transverse rotor dynamic equations, the rotational motion equation, and the motor dq axis model to obtain a simplified electromechanical coupling equation set. The proposed model preserves the main physical transmission chain from bearing defect to electrical response. The model provides a clear theoretical basis for analyzing fault propagation mechanisms and for developing current based diagnostic methods for spacecraft flywheel systems.
Wu, Haolong, Li, Yuqing
BEARING, BALL, AIRFRAME, ANTIFRICTION, SELF-ALIGNING, DOUBLE ROW, HEAVY DUTYAS27643E (Current)10/9/2026
ACBG Rolling Element Bearing Committee
BEARING, BALL, AIRFRAME ANTIFRICTION, PULLEYAS21443D (Current)10/2/2026
ACBG Rolling Element Bearing Committee
Methods for Designing Rotating Components for Compliance to ISO 1940 Balance Requirements using Generic 3D CAD Software2026-01-75659/22/2026
The benefits of specifying balance requirements in terms of an ISO 1940 balance quality grade instead of traditional mass-distance based requirements are discussed along with methods to convert ISO 1940 balance quality grades into permissible imbalance limits at the bearing supports. Methods are developed to determine the expected imbalance values at bearing supports using mass property data from generic 3D CAD software packages without the need for Finite Element Analysis. Practical exercises are presented using these methods to assess a part’s compliance to ISO 1940 while still in the conceptual 3D CAD design stage. These practical exercises cover the selection of appropriate geometric tolerances to ensure part balance without the need for post fabrication balancing as well as the design of nonsymmetrical components for ISO 1940 balance compliance. Citation: J. Srodawa, “Methods for Designing Rotating Components for Compliance to ISO 1940 Balance Requirements Using Generic 3D CAD Software,” In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 11-13, 2026.
Srodawa, John
Plain Spherical Bearing Radial and Axial Clearance MeasurementARP5448/8B (Current)9/21/2026
This test method provides a guidance for determining the total free play between the ball and outer ring of a spherical bearing when measured in both the radial and axial directions. Bearings covered by this test method include all plain spherical-type bearings, both self-lubricated (lined) and metal-to-metal.
ACBG Plain Bearing Committee
Design Considerations for Optimizing the Wheel Bearing Outer Ring Bolt-Mounting Pattern for Reduced Drag2026-01-08309/14/2026
Electric vehicles (EVs) impose more demanding operating conditions on wheel bearing systems due to increased vehicle mass, higher drive torque, and the need to maximize energy efficiency and driving range. These factors elevate the loads transmitted through the bearing to knuckle joint and often require higher clamp loads to ensure joint integrity. However, higher clamp loads amplify distortion of the wheel bearing outer ring, increasing rotational drag and reducing bearing durability. Controlling outer ring distortion is therefore critical for EV wheel bearing design, as well as for high performance vehicles that experience severe lateral loads at the hub to knuckle interface. This paper investigates key design considerations for optimizing the wheel bearing outer ring and its mounting interface to minimize distortion under elevated clamp loads. A comprehensive CAE-based Design of Experiments (DOE) is used to evaluate the influence of multiple bolt-mounting patterns including rectangular, square, and trapezoidal configurations and the relative alignment of the bolt pattern between the outer ring and knuckle. The study also compares the performance of M12 and M14 fastener variants across loading conditions representative of EV and high-performance applications. The results identify geometric and interface design parameters that significantly reduce outer ring out of roundness, thereby lowering drag torque and improving long-term bearing life.
Mandhadi, Chaitanya Reddy, Lee, Seungpyo, Bovee, Benjamin, Callaghan, Kevin
Mechanical Properties and Freeze-Thaw Resistance of Modified Portland Cement-Stabilized Soil for Road Engineering2026-99-15809/11/2026
Subgrade soil is related to the load on the upper part of the road, and its properties will affect the road surface conditions. Frost-thaw action will damage the soil in cold regions. This study focuses on the fine-grained sand in Jilin affected by seasonal frost-thaw, and explores the effects of mixing amount (0% - 6%), curing time (7 days, 28 days), and frost-thaw cycle times (0, 5, 10, 20 times) on the DRM (dynamic resilient modulus) and UCS (unconfined compressive strength) of Portland cement-stabilized soil. The results are: the increase of mixing amount and the extension of curing time will both increase the UCS and DRM; frost-thaw cycles will reduce the UCS and DRM. Roads in cold regions need to use 4% modifier mixture for maintenance for 28 days to achieve strength stability. Heavy subgrades use 6% modifier to obtain the best stiffness load - bearing. This study has insightful guidance for subgrade material improvement in seasonal frozen soil regions.
Wang, Shujuan, Duan, Yonggang, Qin, Weijun, Shen, Ruoting, Jin, Chenguang
Rolling Element Bearing No-Load Torque TestARP5483/1B (Current)9/9/2026
This test method outlines the recommended procedure for performing the no-load rotational starting torque test on airframe rolling bearings. Bearings covered by this test method shall be antifriction ball bearings and spherical roller bearings.
ACBG Rolling Element Bearing Committee
BEARING, BALL, AIRFRAME, ANTIFRICTION, HEAVY DUTYAS27640F (Current)9/9/2026
ACBG Rolling Element Bearing Committee
Dynamic Characteristics Analysis of Needle Roller Bearings in Planetary Gear Trains with Consideration of Inner Bore Spalling Defects of Planet Gears2026-99-12799/4/2026
Driven by the growing demand for higher efficiency and load-bearing capacity in fields such as new energy vehicles and heavy-duty engineering machinery, planetary gear sets are increasingly operating at elevated rotational speeds, coupled with a corresponding expansion of their revolution radii. This dual trend directly induces a substantial surge in centrifugal acceleration acting on the internal needle roller bearings. Under the cyclic stress inherent to transmission operations, such enhanced acceleration not only accelerates the initiation of spalling faults on the inner bores of planet gears but also exacerbates the propagation and deterioration of these faults throughout the service life. To elucidate the influence mechanism of inner bore spalling on the dynamic response of planetary gear bearings, this study develops a specialized dynamic model. This model explicitly incorporates the compound kinematic effects of simultaneous rotation and revolution, thereby ensuring a high-fidelity reconstruction of actual operating scenarios. The research systematically investigates how different spalling types and dimensional parameters affect the system’s dynamic behavior. Numerical results demonstrate a positive correlation between the severity of the spalling defect and the dynamic response intensity. Specifically, the expansion of defect dimensions under harsh operating regimes markedly exacerbates both the contact impulses at the needle-roller interface and the overall vibration acceleration amplitudes. Notably, the amplitude increment of the needle rollers is far more pronounced than that of other components. These findings enrich the theoretical understanding of fault-induced dynamic responses in planetary gear systems and provide a solid theoretical and model-based foundation for optimizing the fault diagnosis, condition monitoring, and maintenance strategies of the associated needle roller bearings.
Zou, Desheng, Lai, Junbin, Guo, Wei, Dong, Peng, Xu, Xiangyang, Sun, Qiang
A Simultaneous Impulse and Oscillatory Component Decomposition Method for Fault Diagnosis of Rolling Bearings2026-99-12049/4/2026
Due to the interference of oscillatory components and noise, the periodic impulses associated with localized bearing faults become difficult to extract, leading to unreliable diagnostic performance. To solve this problem, the study proposes a simultaneous impulse and oscillatory component decomposition method (SIOCD). The method designs and solves a novel optimization model to decompose oscillatory components and fault impulse components from noisy vibration signals. To achieve component separation in the optimization model, distinct penalty functions are introduced for oscillatory and impulse components. For oscillatory components, a regularization term is applied to achieve their extraction by minimizing the component bandwidth in the frequency domain. For impulse components, a penalty function is designed to achieve their decomposition by enhancing both sparsity within groups (SWG) and sparsity across groups (SAG) in the time domain. Then, an iterative solver is derived using an alternating minimization framework and the majorization-minimization (MM) algorithm. Finally, the proposed method’s effectiveness is demonstrated through comprehensive simulation and experimental analyses, and the results demonstrate that it achieves superior performance over existing approaches in fault feature extraction and enhancement.
Sun, Haoran, Zhang, Jinduo, Han, Tianyu, Shi, Xi
Study on the Effect of NaNO 3 +NaClO 3 Electrolyte on the Corrosion Resistance of the Oxide Layer on M50 Aviation Bearing Raceway2026-99-12839/4/2026
In the electrochemical machining (ECM) process of the M50 bearing raceway, the oxide layer’s corrosion resistance exerts a notable impact on the machining efficiency. To achieve high-efficiency ECM of M50 bearing raceways, the electrochemical impedance spectroscopy (EIS) testing technique was adopted to conduct systematic research on the anti-corrosion performance of the oxide layer on M50 bearing raceways under different ECM processing parameters (polarization voltage, polarization time, inter-electrode gap). Then, the impact of different processing parameters on the oxide layer’s corrosion resistance was revealed. The results show that the corrosion resistance of the oxide layer decreases with the increase of the polarization voltage and polarization time, and increases with the increase of the interelectrode gap. Based on this law, in the actual ECM process, the rapid formation of oxide layer can be promoted by adjusting the polarization time, increasing the polarization voltage and reducing the interelectrode gap, and finally, the efficiency of ECM can be improved.
Wu, Jianxing
BEARING, BALL, AIRFRAME, ANTIFRICTION, DOUBLE ROW, HEAVY DUTY, CORROSION-RESISTANT NITROGEN STEEL (CREN)AS27644/1B (Current)8/24/2026
ACBG Rolling Element Bearing Committee
BEARING, ROLLER, NEEDLE-SINGLE ROW, HEAVY DUTY, SELF-ALIGNING, TYPE III, ANTIFRICTION, INCHAS24463F (Current)8/24/2026
ACBG Rolling Element Bearing Committee
Plain Bearing Radial Limit and Ultimate Load TestsARP5448/1B (Current)8/18/2026
This test method outlines the recommended procedure for performing radial limit load and ultimate load tests on low-speed airframe and high-speed helicopter rotor head bearings.
ACBG Plain Bearing Committee
Analysis of the Influence of the Centroid Distribution of the Raft on the Shafting Alignment2026-99-03048/14/2026
Aiming at the problem of shaft alignment disturbed by the centroid distribution of the raft in the ship propulsion system, the quantitative influence of centroid offset on bearing load distribution and axis deformation is revealed. Based on the theory of an elastically supported continuous beam, the finite element model of the raft-shaft coupling system is established. By adjusting the position of the raft counterweight mass point (longitudinal offset range ±0.5 m) to simulate the centroid change, the static solution algorithm is used to analyze the key parameters, such as bearing load and axis alignment accuracy, under multiple groups of centroid offset conditions. It is concluded that when the centroid of the raft moves to the propeller end, the load of the 1# and 2# bearing near the propeller end increases, and the load of the 3# and 6# bearing near the thrust plate end decreases. The lateral offset of the center of mass increases, the axial offset at the stern bearing increases, the maximum deflection of the shafting increases, and the deformation of the raft structure increases. The centroid distribution of the raft is a disturbance source of the shafting alignment state, and its offset will reconstruct the bearing load distribution and cause the axis deformation. It is recommended to control the lateral offset of the center of mass at the design stage and reserve the dynamic compensation margin for the shafting alignment.
Yin, Hong, Jin, Yong, Wang, Jun, Tian, Jiabing
Influence of Roundness and Geometric Errors on Lubrication Performance of Engine Journal Bearings2026-99-03218/14/2026
This paper focuses on the critical issue of lubrication performance in journal bearing manufacturing, employing numerical simulation techniques to investigate how manufacturing errors from processing accuracy impact lubrication behaviors. As core components in mechanical systems—especially diesel engine crankshaft bearings operating under complex conditions—journal bearings’ lubrication performance directly determines equipment stability, energy efficiency, and service life. Manufacturing deviations-induced poor lubrication can cause increased friction, severe wear, or even failures, underscoring the research’s practical value. The study constructs a refined numerical model based on the Navier-Stokes equations within the Computational Fluid Dynamics (CFD) framework, ensuring it reliably depicts fluid flow in bearing clearances. It then systematically analyzes the lubrication responses of diesel engine crankshaft bearings under diverse operational scenarios, varying key manufacturing-related parameters: roundness degrees and clearance dimensions, which mimic real production discrepancies like tool wear or machining vibration. Additionally, the research explores shaft center trajectory variations under two extreme operating conditions, as shaft movement reflects the lubrication film’s loadbearing and stability capacities. Surface roundness and clearance are identified as pivotal to journal bearing performance: they significantly alter oil film thickness distribution—critical for avoiding metal contact—and determine the maximum fluid pressure within bearings, a key load-bearing indicator. Moreover, the amplitude and phase angle of roundness fluctuations (often overlooked) exert substantial impacts on lubrication stability and load-bearing properties, offering insights for optimizing manufacturing processes to mitigate such adverse effects: -Journal bearings. -hydrodynamic lubrication. -Form error.
Liu, Jun, Liu, Deliang
Bearing, Ball, Bellcrank, Antifriction, AirframeAS6038B (Current)8/10/2026
ACBG Rolling Element Bearing Committee
Research on Corrosion and Friction Behaviors of 8Cr4Mo4V Bearing Steels in Corrosive Medium Environments2026-99-10068/7/2026
Corrosion-wear damage behavior affects the bearing life and reliability seriously in a corrosive environment. The accurate evaluation of the tribocorrosion behavior of 8Cr4Mo4V bearing steel samples is critical for the application and protection of bearings. The present work seeks to establish the relationship between laboratory salt spray accelerated experiments and the corrosion of 8Cr4Mo4V steel samples in real outdoor marine atmosphere exposure, and investigate the tribological behavior in the corrosion-wear process under artificial seawater. Results show that salt spray corrosion tests can well simulate the corrosion of 8Cr4Mo4V steels in marine atmospheric exposure. The tribocorrosion performance of 8Cr4Mo4V steels under artificial seawater conditions is affected by the temperature effect of the corrosive liquid and the working conditions. Increased normal load and reduced rotational speed can improve the anti-friction performance. This work offers the possibility and reference of precise control of corrosion-wear-coupled damage failures for bearings.
Zhao, Chao, Ying, Lixia, Nie, Chongyang, Zhu, Tianlin, Sun, Dong
Dynamic Response Analysis of RV Reducers with Time-Varying Stiffness2026-99-09088/7/2026
As a high-precision transmission core component, the RV reducer’s performance depends on the time-varying stiffness of its core components. Building a time-varying stiffness model is essential for studying its dynamic characteristics. This paper addresses the lack of key factors in existing dynamic studies by creating a multi-factor coupled dynamic model. It analyzes the time-varying stiffness of the crankshaft bearing, involute gear, and cycloid gear-pin gear. The study also focuses on building a dynamic analysis model for the crankshaft bearing. By measuring changes in oil film thickness and initial assembly clearance caused by temperature rise, it explains how combined clearance affects bearing performance. To verify the model, a domestic RV reducer is modeled and assembled in SolidWorks. The simplified model is imported into ADAMS for simulation. Under set load and speed conditions, dynamic parameters like angular velocity and acceleration of core components are obtained. This provides a more scientific analysis method and data support for understanding the dynamic characteristics and improving the transmission performance of RV reducers.
Xuan, Liang, Teng, Shaowei, Huang, Ruizhe, Wan, Zefu, Shao, Mengqi, Yu, Zhishen, Wang, Ziyue
Analysis of the Impact on Ride Comfort from Splitting the Unsprung Mass in Vehicle Modeling2026-01-50578/6/2026
The study was conducted to investigate the differences in ride comfort analysis between treating the unsprung mass as a whole and modeling it separately. A classical two-degrees-of-freedom single-wheel vehicle vibration model and a three-degrees-of-freedom single-wheel vehicle vibration model with split unsprung mass were established, with their state-space descriptions determined. The fundamental vibration response quantities of both models were identified, and time-domain simulations under random road excitation were performed using MATLAB/Simulink. The results indicate that the two modeling approaches exhibit minimal differences in ride comfort analysis for the sprung mass, but there are certain differences for the unsprung mass. Additionally, for the three-degrees-of-freedom single-wheel vehicle vibration model with split unsprung mass, the axle-to-wheel mass ratio was introduced to analyze the changes in the fundamental vibration response quantities when the unsprung mass increases by a fixed value and is distributed differently between the axle and the wheel. The results show that variations in the axle-to-wheel mass ratio have no significant impact on the vibration characteristics of the sprung mass. Reducing the mass ratio, i.e., transferring part of the unsprung mass to the wheel, can somewhat reduce the vertical acceleration of the unsprung mass, but it will slightly increase the relative dynamic load on the wheel. Finally, the other two models were simplified by combining the two masses connected by the bearings.
Jie, Li, Wei, Deng, Chengyu, Li
Plain Bearing Test MethodsARP5448C (Current)8/3/2026
This SAE Aerospace Recommended Practice (ARP) establishes methods for testing airframe plain bearings. The purpose of ARP5448 and its associated slash sheets is to document test methods commonly used to evaluate airframe bearings. These test methods may be referenced in specifications, part standards, purchase orders, etc., when the test is deemed appropriate to the intended use of the bearing by the end user of the bearing. These test methods are not intended to encompass every conceivable requirement for an airframe bearing. The end user of the bearing must exercise engineering judgment to determine the most appropriate standard and/or nonstandard tests for the application.
ACBG Plain Bearing Committee
Why your bearing isn't enough: A guide to designing a maintenance-free pivot26TOFHP08_068/1/2026
Engineers designing pivot points for outdoor and heavy-duty equipment have long accepted the familiar routine: grease it, run it, regrease it and repeat. This approach may work well enough. But as equipment pushes into harsher environments and tighter service windows, “well enough” is no longer the standard. Maintenance-free pivots - pivots that run dry, resist corrosion and hold their tolerances through seasons of hard use - offer an increasingly compelling alternative. Designing one requires rethinking what a pivot point actually is, with most engineers focusing only on the bearing itself. While this instinct is understandable, it's also incomplete. A pivot consists of a bearing, shaft and housing working together, requiring a systems-level approach. Optimize only one element and you may still end up with a failure.
Prokopec, John
Pseudo-Label-Guided Dual-Supervised Alignment for Bearing Fault Diagnosis2026-99-02337/31/2026
The inconsistency in bearing data distributions under diverse conditions often affects the representations of the faulty data and leads to indistinct decision boundaries and even negative transfer resulted from overlapping class distributions, greatly limiting the accuracy of the diagnosis model. To cope with the challenge, a pseudo-label-guided dual-supervised alignment (PDSA) method is developed for bearing fault diagnosis across diverse operating scenarios in this paper. To address the fixed alignment strategy issue, an adaptive distribution alignment layer is incorporated to ResNet18 to achieve dynamic data distribution alignment under varying condition, To enhance classification performances, a dual-supervised mechanism, comprising shallow-layer supervised contrastive learning is introduced through target domain pseudo-labels in target domain and deep-layer regularization class consistency. Experiments on two publicly available bearing datasets demonstrated this model realizes refined class-level alignment, strengthens fault states representation, and shows notable superiority in both accuracy and robustness.
Sun, Hao, Ren, Shijin, Gu, Zhangqing
Development and Experiment of Rolling Friction and Wear Testing Machine Based on LabVIEW2026-99-02457/31/2026
To investigate the friction and wear characteristics of rolling bearings under various operating conditions, this paper develops a ring-block type rolling bearing friction and wear testing machine based on LabVIEW. The device achieves rotational friction by regulating the speed with a motor and applies the test load using a lever and weight loading method to simulate the actual working conditions of rolling bearings. The testing machine integrates a high-frequency response force sensor with a high-sampling rate data acquisition system, and combines with the LabVIEW platform to achieve real-time collection, processing, and display of friction force. Using a rolling bearing with a diameter of 50mm as the test object, continuous testing was conducted for 100 s under the conditions of a speed of 500r/min and a load of 50N. The experimental results show that the friction coefficient fluctuated significantly in the early stage of the test (the first 20s), and then stabilized. After stabilization, the average friction coefficient measured was approximately 0.005, which is highly consistent with the theoretical value, verifying the accuracy and reliability of this machine. The testing machine has a compact structure and is easy to operate. It is suitable for friction performance testing of various types of rolling bearings and provides an effective experimental means for the tribological research of rolling bearings.
Xiao, Supeng, Hu, Rui, Xu, Chunxia, Liu, Yang, Chen, Binhua
Fatigue Life Prediction and Improvement of Supporting Structures under Cyclic Highpressure Impact2026-99-01157/31/2026
Under cyclic ultra-high-pressure impact loads, structures often experience local fractures due to insufficient initial fatigue life (low-cycle fatigue). This article focused on a certain ultra-high-pressure support structure and established a dynamic model based on load transfer characteristics to simulate the transient stress-strain response under impact loads. On this basis, a low-cycle fatigue life evaluation method was used to predict the fatigue life of the structure about 362 times, which was significantly different from the required indicators for structural fatigue life. In response to the problem of high loadbearing capacity on the structural support surface and significant stress concentration at the root, the structural load-bearing method has been optimized. Calculation analysis showed that after optimization, the structural stress was greatly improved, the bearing capacity of the support surface was reduced by 25 %, and the fatigue life of the structure was increased from 362 times to 4208 times, an increase of about 10 times. The optimized structure has been verified through 2000 tests without any fracture, meeting the requirements for the service life of the structure.
Wang, Shuman, Ning, Bianfang, Ma, Amin, Zhang, Fanfan
Study on Stiffness Model of Bump Foil in Bump Foil Gas Bearings Based on Ansys Simulation Considering Axial Variable Loads2026-99-01747/31/2026
To address the inaccuracy of existing models in describing the stiffness distribution along the axial direction of bump foils, this study first establishes a simulation model applicable to bump foils based on Ansys Workbench. Specifically, by applying axial variable load at a node that matches the distribution of actual operating conditions, the deformation and stiffness characteristics of the bump foil are investigated. The research results show that, compared with the classic Heshmat model, the bump foil stiffness is not uniformly distributed in the axial direction; instead, it exhibits a trend of being higher in the middle and lower at both ends. Notably, when the nominal stiffness values are similar, the axial end displacement obtained from the Ansys simulation differs significantly from the result calculated by the Heshmat model, with the deviation reaching up to 17.7% of the peak displacement from the latter. Furthermore, this study also systematically analyzes the influence of the laws of the bump foil’s curvature radius, length, and friction coefficient on its stiffness.
Wu, Yixuan, Shi, Yiming, Zhu, Jianjun, Liu, Jiajie
Study on the Contact Stress Distribution and Calculation Method of Cylindrical Roller Bearings Considering Clearance Changes2026-99-01247/31/2026
The distribution of contact stress in roller bearings has a significant impact on operational performance and safety. Firstly, we established a bearing clearance change model that combines interference fit and thermal expansion effects. Then, we studied the clearance changes of key parameters’ influence under different operating conditions. Using Hertz contact theory, we analyze the nonlinear coupling relationship between clearance changes, load distribution, and contact stress. Through MATLAB analytical calculations, load and stress distribution contour maps were obtained under typical operating conditions, which provided theoretical support for bearing optimization design and reliability analysis. The result depicts that an increase in interference fit and temperature difference leads to clearance decrease, triggering a redistribution of contact stress. As clearance decreases, the maximum contact stress exhibits a nonlinear growth trend. To further enhance engineering practicality, this paper uses the MATLAB platform to develop a visualization of digital image processing software. The software enables interactive analysis throughout the entire process of clearance input, stress calculation, and graphical display.
Pang, Yiqing, Cai, Hongbin, Ren, Siyang
Cross-Condition Bearing Multistage Degradation Identification Based on Health Indicator Matrix and Transition Sample Enhanced Network with Multi-Branch Encoding2026-99-08587/30/2026
Precisely detecting multi-stage degradation (MD) in rolling bearings is crucial for keeping equipment in good shape. Yet, health indicator (HI) crafted with current single-method strategies often can't balance degradation sensitivity and monotonicity across different operating conditions. Also, common MD detection methods struggle to spotransitional samples between degradation stages in cross-condition settings. To tackle these challenges, this paper introduces a new cross-condition MD detection approach for bearings, which relies on a health indicator matrix (HIM) and a transition sample enhanced network with multi-branch encoding (TSEN-MBE). First, a degradation-sensitive health indicator (DSHI) is constructed by integrating the least absolute shrinkage and selection operator (LASSO) algorithm — with comprehensive fault frequency energy (CFFE) as the regression target — and the grey wolf optimizer (GWO), capturing intrinsic degradation characteristics of bearings. Meanwhile, to enhance the monotonicity of unsupervised HIs, a time-weighted Wasserstein distance (TWWD) metric is proposed by incorporating temporal degradation features into the Wasserstein distance-based HI construction. The DSHI and TWWD are subsequently combined to generate the HIM. This HIM serves as the driving force for the Gath-Geva (GG) fuzzy clustering algorithm, enabling it to adaptively allocate MD labels according to varying operating conditions. Ultimately, the TSEN-MBE model is constructed, employing multi-branch Transformer encoders integrated with multi-head attention mechanisms to encode and combine heterogeneous features. A joint loss (JL) function — comprising transition sample enhancement (TSE), local maximum mean discrepancy (LMMD), and cross-entropy (CE) losses — is designed to enhance the recognition of transitional samples and improve cross-condition MD identification accuracy. Experimental results on the XJTU-SY dataset validate the effectiveness and superiority of the proposed method, showing that DSHI achieves the highest average degradation angles, TWWD obtains optimal monotonicity, and TSEN-MBE outperforms comparative methods in cross-condition recognition tasks.
Ma, Jinghua, Wei, Lai, Hu, Guangqiao, Yu, Xiaoxia
BEARING, BALL, ANTI-FRICTION, AIRFRAMEAS20218C (Current)7/24/2026
SCOPE IS UNAVAILABLE.
ACBG Rolling Element Bearing Committee
Plain Bearing No-Load Rotational Breakaway Torque MeasurementARP5448/5C (Current)7/24/2026
This test method provides a procedure for measuring no-load rotational breakaway torque of self-lubricating spherical bearings.
ACBG Plain Bearing Committee
Analysis of the Cause of Knocking Noise in a Marine Dual-Power Dual-Branch Transmission Gear System2026-99-16507/24/2026
This study investigates the knocking noise phenomenon in a marine dual-power dual-branch transmission gear system. Vibration mechanisms are analyzed, and potential failure modes are assessed. System vibration data were evaluated using time-domain and frequency-domain methods. Results show that overall vibration levels remained within acceptable limits, with no indication of imminent failure. Physical inspection confirmed that the shaft, gears, bearings, housing, and installation met specifications, with no observed performance degradation or structural damage. By correlating noise occurrence with vessel loading conditions, a strong relationship was identified among gear transmission torque, the power distribution ratio between high-and low-pressure turbines, and the onset of knocking. Specifically, under low-load conditions, uneven power and torque distribution among the four gear branches led to insufficient loading on the low-pressure side. This light-load state induced instability in the low-pressure gears, resulting in periodic tooth disengagement or back-side tooth contact, which is established as the root cause of the knocking noise.
Gu, Chengzhong, Xu, Hanwei, Luo, Rirong, Ren, Fushan
Evaluation of Structural Service Performance of Low-temperature Modified Asphalt Pavement based on Peavy-Duty traffic Engineering2026-99-16457/24/2026
Relying on the reconstruction project, the low-temperature modified asphalt pavement significantly reduces the construction temperature of the asphalt mixture by 40 °C compared with the traditional asphalt pavement, and improves the road performance of the material. By comparing the two mixture rolling schemes, the compaction effect of scheme 2 is better. For AC-13 mixture, the flexural tensile strength of USP-SBS composite modified asphalt mixture is 0.67 MPa higher than that of SBS modified asphalt mixture, and compared with SBS modified asphalt mixture, the final rut depth of USP-SBS composite modified asphalt mixture is 2.68 mm shallower than that of SBS modified asphalt mixture, and the total deformation rate is 43.8% lower than that of the latter. The post-construction quality evaluation shows that the stability of the low-temperature modified asphalt pavement test section under the bearing capacity and high-temperature-water coupling is better than that of the conventional road section, and the low-temperature stability is comparable to that of the two. This innovative application not only achieves energy saving and emission reduction but also provides a new solution for road construction under heavy traffic conditions.
Liu, Chuanfeng, Xu, Ke, Shi, Zheng, Hao, Jidong, Zhao, Liandi, Xianwei, Wang
BEARINGS, PLAIN, SELF-LUBRICATING SELF-ALIGNING, HIGH SPEED OSCILLATION -65 TO +160 °FAS81819/1B (Current)7/21/2026
SCOPE IS UNAVAILABLE.
ACBG Plain Bearing Committee
Plain Bearing Wear MeasurementARP5448/7A (Current)7/20/2026
This standard details two methods of inspecting PTFE lined spherical or journal bearing wear outside the test apparatus. The methods described herein are applicable only to bearings which were unidirectionally loaded and the area of sliding wear is known and held constant throughout the dynamic test. The two methods described are: a Destructive Inspection - Cut and measure (not applicable to molded liners) b Nondestructive Inspection - Radial play (gauge) measurement
ACBG Plain Bearing Committee
BEARING, BALL, AIRFRAME, ANTIFRICTION, DOUBLE ROW, HEAVY DUTYAS27644E (Current)7/13/2026
SCOPE IS UNAVAILABLE.
ACBG Rolling Element Bearing Committee
Adaptive Class-Incremental Learning Intelligent Fault Diagnosis Method for Unmanned Aerial Vehicle Rolling Bearings2026-99-05967/10/2026
As a key component of unmanned aerial vehicles (UAVs), the stable operation of motor bearings is of vital importance to the stability of UAVs. In view of the incomplete data set in the actual diagnosis process, samples not encountered during model training are highly likely to appear. This paper proposes an Adaptive Class-Incremental Learning(ACIL) intelligent fault diagnosis method. This method construct a ResNet framework embedded with Coordinate Attention as the base architecture for class-incremental learning. Furthermore, the Information Preservation Example Selection(IPES) method is utilized to alleviate catastrophic forgetting and update the model from the previous phase using knowledge distillation under coordinate attention. The effectiveness of this method is verified through experiments on the bearing test dataset. The results show that, both average incremental accuracy and average incremental forgetting rate achieve state-of-the-art performance, which means that the performance of the proposed method outperforms than those of other methods.
Song, Ziyang, Lu, Jiantao, Wu, Wei, Li, Shunming
A Novel Rotating Component Comprehensive Diagnostic Network Based on Stacked Auto Encoders and Sparse Filter Combined with Generative Adversarial Network2026-99-05347/10/2026
Nowadays, the majority of intelligent fault diagnosis approaches are still centered on individual faulty components, while only a limited number of models are capable of performing integrated diagnosis for rotating systems that consist of shafts, bearings, and gears. Under variable-speed operating conditions, the large scale of vibration data further complicates the process of effective feature extraction. To improve these challenges, this study develops a comprehensive diagnostic framework for rotating components, termed WGAN-SAFC. The proposed architecture integrates a Wasserstein Generative Adversarial Network (WGAN) with a hybrid structure of stacked autoencoders and sparse filtering (SAFC). SAFC integrates the feature-learning capability of SAE and the sparsity-driven representation of SF, while incorporating adversarial data generation to address sample imbalance and enhance fault diagnosis performance. Experimental verification on collected vibration datasets demonstrates that WGAN-SAFC achieves superior diagnostic accuracy and robustness compared with existing methods.
Li, Shunming, Feng, Mengqi
Vibroacoustic Analysis and Optimisation of an Electric Refrigerant Scroll Compressor2026-01-07226/20/2026
In electrified vehicles, auxiliary components can represent a dominant source of noise, one of which is the refrigerant scroll compressor. Compared with vehicles equipped with internal combustion engines, electrified vehicles require larger refrigerant compressors, as thermal management is needed not only for the passenger compartment but also for the battery and electric drive components. Excitation mechanisms within the compressor, arising from the cyclic compression process and the eccentric motion of the scroll, induce housing vibrations and result in airborne sound radiation. To investigate the vibroacoustic noise generation mechanisms of a scroll compressor, operational vibrations were analysed using accelerometers and three-dimensional laser scanning vibrometry. In addition, the radiated sound was characterised using microphones and near-field sound intensity measurements. The results demonstrate a strong correlation between surface vibrations and airborne sound radiation, with the vibroacoustic behaviour being dominated by speed-dependent tonal components. Pronounced vibration and sound radiation levels occur when excitation orders coincide with rigid-body modes of the mounting system or structural eigenmodes of the compressor housing. Based on these findings, a constrained-layer damping treatment was applied to selected, highly sound-radiating regions of the compressor housing. Although the overall reduction in sound power was limited due to the high stiffness and predominantly rigid-body behaviour of the housing, local vibration and sound radiation reductions were achieved for structurally flexible components, resulting in a perceptible improvement in subjective sound quality. These results highlight the importance of spatially resolved vibroacoustic analysis for understanding noise generation mechanisms and for guiding targeted optimisation measures for refrigerant compressors.
Saur, Lukas, Beer, Gabriel, Fritzsche, Marco, Becker, Stefan
Influence of Common-Mode Voltage Reduction Techniques on High-Frequency Sideband Vibrations in IPMSM Drives for EVs2026-01-06956/20/2026
Space vector pulse width modulation (SVPWM) induces common-mode voltage (CMV) in three-phase voltage-source inverters, producing steep voltage edges that can lead to high leakage currents. In electric drive applications, these currents accelerate motor bearing degradation and may cause winding insulation failure. Active-zero-state PWM (AZSPWM) and near-state PWM (NSPWM) have been proposed as alternative modulation strategies to mitigate CMV and reduce drive degradation. This paper investigates the noise, vibration, and harshness performance of AZSPWM and NSPWM in comparison with conventional SVPWM. The proposed CMV reduction schemes are evaluated in terms of both CMV mitigation and their impact on high-frequency sideband vibration harmonics. Experimental results demonstrate that the CMV reduction strategies are highly effective in lowering CMV levels relative to SVPWM; however, this benefit is accompanied by an increase in vibration levels, which may adversely affect the mechanical integrity of the drive system despite the reduction in bearing leakage currents.
Khamis, Mahmoud Aly, Tatar, Andrei Alexandru, Repecho, Victor, Doria-Cerezo, Arnau
BEARING, BALL, AIRFRAME, ANTI-FRICTION, SELF-ALIGNING, LIGHT AND HEAVY DUTYAS27645D (Current)6/18/2026
SCOPE IS UNAVAILABLE.
ACBG Rolling Element Bearing Committee
BEARING, BALL, AIRFRAME, ANTIFRICTION, EXTERNAL SELF-ALIGNING, EXTRA LIGHT DUTY CORROSION-RESISTANT NITROGEN STEEL (CREN)AS27648/1A (Current)6/15/2026
SCOPE IS UNAVAILABLE.
ACBG Rolling Element Bearing Committee
Rolling Element Bearing Axial and Radial Internal ClearanceARP5483/3B (Current)6/10/2026
This test method outlines the standard procedure for measuring the radial and axial internal clearance of rolling element bearings used in airframe controls.
ACBG Rolling Element Bearing Committee
BEARING, BALL, AIRFRAME, ANTIFRICTION, INTERMEDIATE DUTY CORROSION RESISTANT NITROGEN STEEL (CREN)AS27649/1A (Current)6/9/2026
SCOPE IS UNAVAILABLE.
ACBG Rolling Element Bearing Committee
Hybrid Digital Twin for Aero-Engine Bearing Prognostics: A Physics-Informed Machine Learning Approach to RUL Prediction2026-26-07186/1/2026
Unscheduled maintenance due to the failure of critical components, such as aero-engine rolling element bearings, is a leading cause of costly Aircraft-on-Ground (AOG) events; consequently, current time-based maintenance practices are inefficient and prone to risk. This paper develops a resource-efficient Hybrid Digital Twin (HDT) model for an engine bearing, focusing on the dynamic prediction of spall growth due to Rolling Contact Fatigue (RCF), thereby enabling a condition-based maintenance paradigm. The HDT architecture integrates two core models: (1) a physics-informed model that uses established life and fatigue theory to define initial degradation thresholds, and (2) a data-driven Recurrent Neural Network (RNN), specifically a Long Short-Term Memory (LSTM) network, for dynamic degradation rate modeling. The methodology utilizes a Monte Carlo simulation coupled with RCF progression equations to generate a large, high-fidelity synthetic run-to-failure dataset under varying operational loads, accurately simulating realistic mission profiles. This approach addresses the critical "data scarcity" challenge in aviation. To ensure operational reliability, the framework incorporates Uncertainty Quantification (UQ) using Monte Carlo Dropout and addresses the "Sim-to-Real" gap through Transfer Learning on the NASA IMS bearing dataset. The HDT demonstrates a significant improvement in prognostic accuracy, achieving a Root Mean Square Error (RMSE) reduction of over 71% compared to baseline models. Furthermore, a cost-benefit analysis suggests a potential fleet savings of $240,000 per 100 engines by avoiding false negatives. This computationally efficient approach supports the Digital Engineering Transformation theme by providing a scalable blueprint for the virtual qualification of critical mechanical components.
Mohamed, Abbas
Items per page:
1 – 50 of 3348