Browse Topic: Lubricating greases
For brake and clutch components of aircraft vehicles which require higher mechanical strength and wear resilient, light-weight aluminium composites were developed infusing solid lubricant. In this study, hybrid composites were developed using powder metallurgy route with aluminum alloy AA356 and various amounts of zirconium oxide (ZrO2) (0, 5, 10, 15, and 20 wt.%) as reinforcements. A solid lubricant hexagonal boron nitride (hBN) at a fixed 5 wt.% is considered. Following the appropriate ASTM guidelines, the specimens were mechanically characterized by measuring their density, porosity, micro-hardness, compression strength, impact strength, and flexural strength, among other properties. The findings showed that the composites' mechanical and physical behaviour were greatly affected by the inclusion of ZrO2. Porosity increased as a result of particle clustering and interfacial voids, while density increased gradually as ceramic content increased. Consistently increasing ZrO2 addition led to micro-hardness improvements; at 20 wt.% reinforcement, values reached their maximum, indicating that the hard ceramic phase contributed to better surface resistance. The best balance between particle reinforcement and matrix continuity was suggested by the compression and flexural strengths peaking at 15 wt.% ZrO2. However, when the addition was raised to 20 wt.%, brittleness and porosity began to marginally deteriorate. Unreinforced and lower ZrO2 composites had superior toughness in impact, whereas materials with a higher content had a poorer energy absorption capacity. The 5 wt.% hBN improved fracture arresting capabilities and helped load transmission over the interface. Inclusion of hBN provides solid-lubricating tribofilm formation that enhances the tribological performance. This study reveals that AA356/ZrO2-hBN hybrid composites have good hardness and compressive strength improvements, with 15 wt.% ZrO2 being the best composition with good strength, toughness, and wear resistance.
Rolling-element bearings in rotorcraft dynamic systems are critical components susceptible to rolling contact fatigue (RCF), a dominant degradation mechanism manifesting through subsurface-initiated spalling, surface micropitting, and fatigue fractures. Robust inspection strategies compliant with EASA and FAA requirements are therefore essential. Traditional methods are often invasive, requiring disassembly, and are susceptible to human-factor errors. Smart Duplex introduces a design-for-monitoring architecture integrating in-situ videoscopic and coherence scanning interferometry (CSI) for high-resolution 3D surface mapping, including under partial grease coverage. This paper details a repeatability and reproducibility (R&R) framework ensuring metric consistency; a maintainability assessment projecting significant man-hour reductions and high availability; certification rationale emphasizing airworthiness improvements via enhanced detectability, workload reduction, and digitized inspection records; and an airworthiness mapping supporting threat assessments, Airworthiness Limitations Section (ALS) entries, and usage-based maintenance credits. By embedding sensing capability and digitizing inspection records, Smart Duplex minimizes downtime, mitigates human-factor errors, and facilitates predictive maintenance, optimizing cost, enhancing performance, and ultimately improving safety.
In the commercial and off-highway sectors, equipment reliability isn't just a maintenance target but a business imperative. Whether it's a long-haul truck on the interstate or a dozer working through dust and rock, these machines operate in some of the most demanding environments on Earth. And while engine design and fuel choice often dominate conversations about performance, the role of grease is just as critical, particularly as equipment is pushed harder and longer under more variable conditions. Over the last decade, heavy-duty grease development has undergone a quiet evolution. Performance expectations have risen sharply. So have the environmental and regulatory considerations that influence formulation decisions.
Using a Defense University Research Instrumentation Program (DURIP) award bestowed last year and plenty of elbow grease, Dr. Frank Narducci, Chair of the NPS Department of Physics, and his Ph.D. student U.S. Navy Cmdr. Jens Berdahl, a former Navy pilot currently pursuing his doctorate through the service’s Permanent Military Professor program, are nearing completion of the first phase of construction in what will be a superlatively precise atomic-based instrument.
The foundation specification (AMS3050) and this category specification (AMS3050/1) cover anti-seize greases conforming to the requirements but using the anti-seize ingredient Copper only.
The overarching objective of the present study is to apply a quasi-two-dimensional approach to analyze the laminar flow of lubricating oil. Lubricating oils are non-Newtonian by nature. For these types of oils, the Sisko fluid model is the most suitable model of the nonlinear stress–strain relationship for these types of oils. It is hoped that by omitting the dependence of flow quantities in one direction, more qualitative information can be obtained on the characteristics of the purely three-dimensional boundary layer flow of lubricating oils. Some of the most familiar flow geometries discussed are steady flow over a flat plate, a corner of a wedge, and a stagnation region; steady flow in a convergent and divergent channel; and impulsively started flow over an infinite flat plate and semi-infinite flat plate. The governing equations of all flow geometries are transformed into nonlinear ordinary differential equations (ODE) using the free parameter transformation. The results are discussed briefly in the graphical presentation.
The foundation specification (AMS3050) and this category specification (AMS3050/9) cover anti-seize greases conforming to the requirements, but using the anti-seize ingredient Graphite+Calcium Fluoride only.
The foundation specification (AMS3050) and this category specification (AMS3050/8) cover anti-seize greases conforming to the requirements but using the anti-seize ingredient Graphite+Aluminum only.
The foundation specification (AMS3050) and this category specification (AMS3050/3) cover anti-seize greases conforming to the requirements but using the anti-seize ingredient Nickel only.
The foundation specification (AMS3050) and this category specification (AMS3050/7) cover anti-seize greases conforming to the requirements, but using the anti-seize ingredient Copper+Graphite+Aluminum only.
The foundation specification (AMS3050) and this category specification (AMS3050/2) cover anti-seize greases conforming to the requirements, but using the anti-seize ingredient Aluminum only.
The foundation specification (AMS3050) and this category specification (AMS3050/5) cover anti-seize greases conforming to the requirements but using the anti-seize ingredient PTFE only. For use only below 600 °F / 315 °C.
The foundation specification (AMS3050) and this category specification (AMS3050/4) cover anti-seize greases conforming to the requirements but using the anti-seize ingredient Molybdenum Disulphide; Graphite only.
The foundation specification (AMS3050) and this category specification (AMS3050/6) cover anti-seize greases conforming to the requirements but using the anti-seize ingredient Nickel and Graphite only.
Engineers, managers, technicians and other automation professionals at most manufacturers understand the value of pretreating metal surfaces of parts to remove corrosion, grease, residue, old coatings, or to roughen the surface of metals prior to coating. By ensuring the items are cleaned down to bare metal, manufacturers can avoid costly warranty issues that result when coatings peel, flake, bubble, or otherwise fail prematurely.
This study reports a simulation model to predict the coating thickness during the Electric Discharge Coating (EDC) process and validates it with experimental analysis. Solid lubricant coating was developed on the mild steel substrate using WS2, and Cu (50:50) based green compact electrodes. The simulation model developed by using COMSOL Multiphysics (5.5) software and the accumulated growth height from the heavy species transport calculated as coating thickness. Experiments with the same input parameters and coating thickness were measured, compared with simulation result and the results show with error fraction of 3% to 12%. Therefore, the present developed simulation model can be employed to predict the thickness of solid lubricant coating by EDC process with minimum error.
The automotive sector has always been closely connected with the lubricants industry, with the latter continuously developing new technologies, specs and products in order to address the evolution in this segment. Electrification represents a significant change in the major powertrains and, thus, it will inevitably affect the selection, development and market share of several types of lubricants, such as lubricating greases. The evolution of the EV/HV segment will increase the demand and the importance of lubricating greases for electric motors. New challenges for grease formulation may arise from the neighboring electric currents and electromagnetic fields and higher energy efficiency requirements. In this paper, the perspectives and the projected evolution of automotive e-mobility is reported and the subsequent influence on the main grease performance requirements are analyzed. Moreover, the alteration in the applications are examined. A series of lubricating grease formulations are prepared, based on polyurea thickener type without additives, and a number of technical properties and parameters are determined in order to evaluate their performance with regards to current requirements and future development trends for greases intended for lubrication in vehicles with electric and/or hybrid powertrains.
This standard applies to the aerospace and defense industries and their supply chain.
This test method provides the capabilities, limitations, and suggested possible applications of TGA as it pertains to the detection of counterfeit electronic components. Additionally, this document outlines requirements associated with the application of TGA including: equipment requirements, test sample requirements, methodology, control and calibration, data analysis, reporting, and qualification and certification. If AS6171/10 is invoked in the contract, the base document, AS6171 General Requirements shall also apply.
Dual mass flywheel (DMF) is an excellent solution to improve the noise, vibration, and harshness (NVH) characteristic of any vehicle by isolating the driveline from the engine torsional vibrations. For the same reason, DMF’s are widely used in high power-density diesel and gasoline engines. However, the real-world usage conditions pose a lot of challenges to the robustness of the DMF. In the present work, by capturing the Real-World Usage Profile (RWUP) conditions, a new methodology is developed to evaluate the robustness of a DMF fitted in a Sports utility vehicle (SUV). Ventilation holes are provided on clutch housing to improve convective heat transfer. Improvement in convective heat transfer will increase the life and will reduce clutch burning concerns. Cities like Mumbai, Chennai, Bangalore, roads will have clogged waters during rainy season. When the vehicle was driven in such roads, water enters inside the clutch housing through ventilation holes. Prolonged usage of vehicle in this condition results in water entering inside the DMF. DMF has grease over the springs to reduce friction. Water entering inside the DMF will reduce the viscosity of grease and subsequently leads to erosion of grease from DMF. This will result in metallic noise concern in Engine ON condition. In the present work, author presents test methodology that shall be used to reproduce the metallic noise concern during development phase. The methodology is the combination of water wading test carried out at 500 mm of water level and subsequently subjecting the vehicle to city drive and high drive profile test of 1000 km. The co-relation was also established with real world failures. Authors also propose design alternatives that shall address metallic noise concern due to water entry. Based on the results of this proposed methodology, the robustness of the DMF could be improved. The paper explains the typical robustness measures needed inside the DMF to avoid real-world NVH failures and the test methodology to evaluate the same.
Rotorcraft, like most machines, require periodic lubrication tasks to ensure continued safe and reliable operation. Optimal lubrication intervals are desired to maintain system performance while minimizing aircraft downtime and maintenance labor. Boeing and AMRRI conducted a Lubrication Optimization Study (LOS) on the H-47 Chinook helicopter to establish the necessary engineering artifacts to define the grease lubrication intervals for selected Drive, Rotor, and Landing Gear components. Grease samples were collected from these components by H-47 operators from multiple nations and submitted for a laboratory analysis to characterize how wear, properties and contaminants change as time and aircraft hours accumulate. The LOS also revealed opportunities to further evaluate and leverage the data produced in this study, including determining superior performance of specific lubricants within the Mil-Spec designation, testing of greases for compatibility5 when mixed, and enhancing new grease cleanliness to extend component life.
The present work aims at investigating the tribological behavior of a newly developed friction materials and its performance is compared with the commercial brake pad under dry sliding conditions. The friction materials were made in the form of cylindrical pin from three different solid lubricants - graphite, molybdenum disulfide (MoS2) and graphene - keeping the other ingredients fixed. The prepared seven samples (BP01- Graphite, BP02- MoS2, BP03- Graphite &MoS2, BP04- Graphene, BP05- Graphene & Graphite, BP06 - Graphene & MoS2, BP07 - Graphene, Graphite & MoS2) were tested in pin and disc machine and compared to investigate the coefficient of friction, wear resistance followed by hardness test and thermal degradation analysis. The results showed that the wear loss and coefficient of friction of the developed friction materials were strongly influenced by the type and percentage of solid lubricants. The performance of the newly developed friction materials is better than the commercial brake pad which signifies that it could be used in commercial automotive applications.
Items per page:
50
1 – 50 of 729