Browse Topic: Maintenance and Aftermarket
The gearbox is a key component of the mechanical transmission system, and its fault diagnosis is essential to the reliability of the equipment. However, obtaining fault samples under actual working conditions for gearbox fault diagnosis is challenging. In this paper, the rigid-flexible coupling dynamic simulation model of the gearbox is established, and the co-simulation of gear normal, crack, and breakage is carried out in the ADAMS and MATLAB environments. The comparison between the simulated and measured signals shows that the simulation method can accurately reflect the key characteristics, such as rotation frequency and meshing frequency, and verify its reliability and accuracy. The research results can provide effective data support for gearbox fault diagnosis and improve the operational safety of mechanical systems.
Current lithium-ion batteries should generally only be charged above 0 °C, as charging below this temperature can promote lithium plating and irreversible degradation. However, conventional pack-level heating elements increase system mass and design complexity. In addition, heat is transferred from outside into the cell, causing the temperature inside the cell to rise slowly. This study evaluates internal Joule heating of cylindrical Li-ion cells using a zero-mean square-wave current excitation and quantifies the associated aging impact. LG INR21700-M50L cells were tested at 0 °C, −10 °C, and −20 °C with three excitation frequencies (50 Hz, 1 Hz, 10 mHz) at 5 A amplitude. Each cycle consisted of 30 min heating followed by 60 min cooling; reference capacity-based state of health (SOH) was assessed every 50 cycles up to 400 cycles. A maximum surface temperature rise of 14.3 K was achieved, with larger temperature rise at lower ambient temperature and lower excitation frequency. Capacity
This SAE Surface Vehicle Technical Information Report, SAE J2836/4, establishes diagnostic use cases between plug-in electric vehicles (PEV) and the electric vehicle supply equipment (EVSE). As PEVs are deployed and include both plug-in hybrid electric (PHEV) and battery electric (BEV) vehicle variations, failures of the charging session between the EVSE and PEV may include diagnostics particular to the vehicle variations. This document describes the general information required for diagnostics and SAE J2847/4 will include the detail messages to provide accurate information to the customer and/or service personnel to identify the source of the issue and assist in resolution. Existing vehicle diagnostics can also be added and included during this charging session regarding issues that have occurred or are imminent to the EVSE or PEV, to assist in resolution of these items.
The automotive air-conditioning service ports task force conducted a field survey with MACS (Mobile Air Climate Systems Association) in June 2021. The scope of this survey was to determine the types of failures reported primarily at member service shops related to automotive air-conditioning service ports.
Researchers discover texts, phone calls, military communication, internal corporate networks all easily eavesdropped on using off-the-shelf equipment. University of California San Diego, La Jolla, CA With $800 of off-the-shelf equipment and months' worth of patience, a team of U.S. computer scientists set out to find out how well geostationary satellite communications are encrypted. And what they found was shocking. Close to half of the communications beamed from satellites to the ground that the researchers were able to listen in on were not encrypted. This included sensitive data including cellular text messages, voice calls, as well as sensitive military information, data from internal corporate and bank networks, and the in-flight online activity of airline passengers.
Researchers from CompPair and the European Space Agency have developed a new composite material for spacecraft with an embedded healing agent. European Space Agency, Paris, France Healable spacecraft structures could soon be possible thanks to cutting-edge composite technology. Swiss companies CompPair and CSEM, and Belgian company Com&Sens have partnered with the European Space Agency (ESA) to modify their self-healing carbon fiber product for use in space transportation. Project Cassandra - an abbreviation for Composite Autonomous Sensing and Repair - includes sensors and a heating element within a composite carbon-fiber material, allowing spacecraft to autonomously repair initial stages of damage.
Static electricity is an electrical imbalance on the surface of a material which can interact with other components having same or different materials. Fluid flow within the hose assembly generates static voltage due to friction caused by fluid flow in pipes, that needs to be appropriately quantified and dissipated. Accumulation of such static charge may lead to sudden discharge leading to spark generation. Spark generation around fuel flow might lead to system failure and failure in aircraft engines. Test experiments were conducted to analyze static voltage generated in hose assembly due to fuel flow with the objective that voltage achieved is within the acceptable range to avoid ESD (Electrostatic Discharge) failure. Procedure includes flow rate monitoring and voltage measurement using fuel as test fluid. The testing revealed that the curvature of the hose affects the readings, highlighting the importance of consistent meter alignment. Using a grounding strap is essential to prevent
This document establishes the minimum training and qualification requirements for ground-based aircraft deicing methods and procedures. All guidelines referred to herein are applicable only in conjunction with the applicable documents. Due to aerodynamic and other concerns, the application of deicing fluids shall be carried out in compliance with engine and aircraft manufacturers’ recommendations. The scope of training should be adjusted according to local demands. There are a wide variety of winter seasons and differences of the involvement between deicing operators, and therefore, the level and length of training should be adjusted accordingly. However, the minimum level of training shall be covered in all cases. As a rule of thumb, the amount of time spent in practical training should equal or exceed the amount of time spent in classroom training.
This Surface Vehicle & Aerospace Recommended Practice offers best practices and a methodology by which IVHM functionality relating to components and subsystems should be integrated into vehicle or platform level applications. The intent of the document is to provide practitioners with a structured methodology for specifying, characterizing and exposing the inherent IVHM functionality of a component or subsystem using a common functional reference model, i.e., through the exchange of design-time data and the application of standard vehicle data communications interfaces. This document includes best practices and guidance related to the specification of the information that must be exchanged between the functional layers in the IVHM system or between lower-level components/subsystems and the higher-level control system to enable health monitoring and tracking of system degradation severity. The intent is to provide an IVHM system that can robustly report the degradation of a given
SAE JA6097 (“Using a System Reliability Model to Optimize Maintenance”) shows how to determine which maintenance to perform on a system when that system requires corrective maintenance to achieve the lowest long-term operating cost. While this document may focus on applications to Jet Engines and Aircraft, this methodology could be applied to nearly any type of system. However, it would be most effective for systems that are tightly integrated, where a failure in any part of the system causes the entire system to go off-line, and the process of accessing a failed component can require additional maintenance on other unrelated components.
This SAE Aerospace Recommended Practice (ARP) outlines the functional and design requirements for a self-propelled belt conveyor for handling baggage and cargo at aircraft bulk cargo holds. Additional considerations and requirements may legally apply in other countries. As an example, for operation in Europe (EU and EFTA), the applicable EN standards shall be complied with.
This SAE Aerospace Recommended Practice (ARP) describes standard methods of heat application to cure thermosetting resins for commercial aircraft composite repairs. The methods described in this document shall only be used when specified in an approved repair document or with the agreement of the Original Equipment Manufacturer (OEM) or regulatory authority.
This Aerospace Recommended Practice (ARP) describes methods of vacuum bagging, a process used to apply pressure in adhesive bonding and heat curing of thermosetting composite materials and metalbond for commercial aircraft parts. If this document is used for the vacuum bagging of other than thermosetting composite materials and metalbond, the fitness for this purpose must be determined by the user. The methods shall only be used when specified in an approved Repair Document or with the agreement of the Original Equipment Manufacturer (OEM).
This SAE Aerospace Information Report (AIR) provides information and guidance for the selection and use of technologies and methods for lubrication system monitoring of gas turbine aircraft engines. This AIR describes technologies and methods covering oil system performance monitoring, oil debris monitoring, and oil condition monitoring. Both on-aircraft and off-aircraft applications are presented. A higher-level view of lubrication system monitoring as part of an overall engine monitoring system (EMS) is discussed in ARP1587. The scope of this document is limited to those lubrication system monitoring, inspection, and analysis methods and devices that can be considered appropriate for health monitoring and routine maintenance. This AIR is intended to be used as a technical guide. It is not intended to be used as a legal document or standard.
This SAE Aerospace Recommended Practice (ARP) document establishes criteria and recommended practices for the use of airborne icing tankers to aid in design and certification of aircraft ice protection systems and components. Several icing tankers are described, along with their capabilities and suggested use. Sample data for these tanker spray systems are included, shown with 14 CFR Parts 25 and 29, Appendix C icing envelopes for continuous maximum and intermittent maximum icing conditions. (Note: In the remainder of this document, the phrase “Appendix C icing envelopes” will be used for brevity.) This ARP is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
This document applies to off-road forestry work machines defined in SAE J1116 or ISO 6814.
The impact of ship airwake on helicopter operations to rear flight decks has been a topic of much research over the past three decades. While generic ships have been developed over the years to enable analysis tool and knowledge development, actual ships can vary significantly, resulting in different airwake features. The study of variations in ship geometry is important both to understand how differences may impact operations, but also to understand the level of geometrical fidelity that is required on ship models undergoing analysis. In Canada, the newly launched (2018) Harry DeWolf-class Arctic Offshore Patrol Ships (AOPS) have unique features that have been studied for their impact on airwake characteristics. This paper explores different geometrical characteristics from the perspective of their operational impacts and also considering their importance for inclusion in simulation. The paper shows that turbulence level is the parameter most affected by the minor variations that were
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