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Journal Article

Numerical Analysis of Armored Fighting Vehicle Escape Hatch Subjected to Mine Blast Loading Using Coupled Eulerian-Lagrangian Technique

2023-03-30
Abstract This article describes the research work taken to compare the effect of air blast and surface-buried mine blast loading on an armored fighting vehicle (AFV) escape hatch, using the coupled Eulerian-Lagrangian (CEL) technique. Two types of escape hatch were considered for the study, namely, the flat plate version and double-side curved-plate version. To evaluate the research methodology used in this investigation, initially, a published experimental work on a circular plate subjected to air blast was chosen and a benchmark simulation was carried out using the CEL technique to establish the simulation procedure. Then the established procedure was utilized for further analysis. It was observed that the variation in the deformation between the published literature and the simulation work was well within the acceptable engineering limits.
Journal Article

Infrared Signature of Fixed and Variable Area C-D Nozzle of Aircraft Engine

2023-01-02
Abstract The use of converging-diverging (C-D) variable area nozzle (VAN) in military aeroengines is now common, as it can give optimal expansion and control over engine back pressure, for a wide range of engine operations. At higher main combustion temperatures (desired for supercruise), an increase in the nozzle expansion ratio is needed for optimum performance. But changes in the nozzle throat and exit areas affect the visibility of engine hot parts as the diverging section of the nozzle is visible for a full range of view angle from the rear aspect. The solid angle subtended by engine hot parts varies with change in visibility, which affects the aircraft infrared (IR) signature from the rear aspect. This study compares the performances of fixed and variable area nozzles (FAN and VAN) in terms of engine thrust and IR signature of the engine exhaust system in the boresight for the same increase in combustion temperature.
Standard

Automotive Gear Lubricants for Commercial and Military Use

2022-05-20
CURRENT
J2360_202205
The gear lubricants covered by this standard exceed American Petroleum Institute (API) Service Classification API GL-5 and are intended for hypoid-type, automotive gear units, operating under conditions of high-speed/shock load and low-speed/high-torque. These lubricants may be appropriate for other gear applications where the position of the shafts relative to each other and the type of gear flank contact involve a large percentage of sliding contact. Such applications typically require extreme pressure (EP) additives to prevent the adhesion and subsequent tearing away of material from the loaded gear flanks. These lubricants are not appropriate for the lubrication of worm gears. Appendix A is a mandatory part of this standard. The information contained in Appendix A is intended for the demonstration of compliance with the requirements of this standard and for listing on the Qualified Products List (QPL) administered by the Lubricant Review Institute (LRI).
Article

Quality management experts provide guidance on AS9100 standard

2021-11-04
Quality management professionals across the global aerospace and defense community are convening for one hour – Wednesday, October 27th, starting at 10 am Pacific Daylight Time (PDT) – to discuss the AS9100 international standard. Register to take part in the free AeroTech webinar, hosted by SAE International and Tektronix, designed to help manufacturers, contractors, and subcontractors throughout the global aviation, space, and defense supply chain keep pace with and meet the requirements of AS9100 international quality management system standard.
Article

Turn growing complexity into competitive advantage through digitalization

2021-03-10
While the pandemic continues, aerospace companies are rising to embrace new and emerging challenges at a time when there’s so much innovation. This innovation can be seen in the emergence of urban air mobility (UAM), the rebirth of supersonic flight, the drive towards a “zero emission” aircraft, and the continued use of autonomous drones for delivery, freight, search & rescue, and defense. There are exciting new developments in space as companies are developing products for commercial exploration and space tourism, and new ways to launch satellites. A new generation of engineering is also emerging in the defense sector and its development of not only aircraft, but also ships, tankers, and even flight trainers.
Standard

Automotive Gear Lubricants for Commercial and Military Use

2021-01-27
HISTORICAL
J2360_202101
The gear lubricants covered by this standard exceed American Petroleum Institute (API) Service Classification API GL-5 and are intended for hypoid-type, automotive gear units, operating under conditions of high-speed/shock load and low-speed/high-torque. These lubricants may be appropriate for other gear applications where the position of the shafts relative to each other and the type of gear flank contact involve a large percentage of sliding contact. Such applications typically require extreme pressure (EP) additives to prevent the adhesion and subsequent tearing away of material from the loaded gear flanks. These lubricants are not appropriate for the lubrication of worm gears. Appendix A is a mandatory part of this standard. The information contained in Appendix A is intended for the demonstration of compliance with the requirements of this standard and for listing on the Qualified Products List (QPL) administered by the Lubricant Review Institute (LRI).
Training / Education

Fundamentals of Fatigue Analysis

Fatigue is a structural failure mode that must be recognized and understood to develop products that meet life cycle durability requirements. In the age of lightweighting, fatigue strength is an important vehicle design requirement as engineers struggle to meet stringent weight constraints without adversely impacting durability. This technical concept course introduces the fatigue failure mode and analysis methods. It explains the physics of material fatigue, including damage accumulation that may progress to product failure over time, and it provides the needed foundation to develop effective fatigue prediction capabilities.
Training / Education

Fluids for Aerospace Hydraulic Systems

This four-hour short course provides an introduction to fluids for aerospace hydraulic systems. Topics covered include an introduction to basics fluid properties, rheology, tribology, and fluid product development. In addition, the history and performance of different classes of fluids are discussed in detail, and specific failure modes such as erosion and sludge formation will be described. Along with an introduction to fluid degradation, information on used oil analysis test methods and interpretation will be provided.
Standard

S400 Copper Media Interface Characteristics Over Extended Distances

2019-07-09
CURRENT
AS5643/1A
This SAE Aerospace Standard (AS) establishes guidelines for the use of IEEE-1394-2008 Beta (formerly IEEE-1394b) as a data bus network in military and aerospace vehicles. It encompasses the data bus cable and its interface electronics for a system utilizing S400 over copper medium over extended lengths. This document contains extensions/restrictions to “off-the-shelf” IEEE-1394 standards, and assumes that the reader already has a working knowledge of IEEE-1394. This document does not identify specific environmental requirements (electromagnetic compatibility, temperature, vibration, etc.); such requirements will be vehicle-specific and even LRU-specific. However, the hardware requirements and examples contained herein do address many of the environmental conditions that military and aerospace vehicles may experience. One should refer to the appropriate sections of MIL-STD-461E for their particular LRU, and utilize handbooks such as MIL-HDBK-454A and MIL-HDBK-5400 for guidance.
Journal Article

Numerical Analysis of Blast Protection Improvement of an Armored Vehicle Cab by Composite Armors and Anti-Shock Seats

2018-12-05
Abstract The objective of this article is to evaluate the effects of different blast protective modules to military vehicle structures and occupants. The dynamic responses of the V-shape integral basic armor, the add-on honeycomb sandwich structure module, and the anti-shock seat-dummy system were simulated and analyzed. The improvements of occupant survivability by different protective modules were compared using occupant injury criteria. The integral armored cab can maintain the integrity of the cab body structure. The add-on honeycomb sandwich armor reduces the peak structural deformation and velocity of the cab floor by 34.9% and 47.4%, respectively, compared with the cab with integral armors only. The integral armored cab with the anti-shock seat or the honeycomb sandwich structures reduces the occupant shock responses below the injury criteria. For different blast threat intensities, the selection of appropriate protective modules can meet protection requirements.
Book

Counterfeit Parts and Their Impact on the Supply Chain, Second Edition

2018-11-15
Why should the supply chain be concerned if their buyers or subcontractors are purchasing counterfeit electronic parts or if their products contain counterfeit electronic parts? If these parts end up in items that are safety critical and security-risk sensitive such as aviation, space, and defense products, whole secure systems can be comprised. As organizations have become aware of counterfeit parts, one of their responses may be to test upon acceptance or prior to receipt. But testing alone may not detect all counterfeits. Possible sources of counterfeits include products that did not meet quality control requirements and were not destroyed, overruns sold into the market place, unauthorized production shifts, theft, and e-waste. The counterfeited electronic part ends up in the supply chain when ordered by an unsuspecting buyer, who does not confirm the originating source of the part.
Magazine

Tech Briefs: August 2018

2018-08-01
Designing a High-Speed Decoy Unmanned Aerial Vehicle (UAV) Using Thermoplastics in Aerospace Applications In-Flight Real-Time Avionics Adaptation Using Turbine Flow Meters for Aerospace Test and Measurement Applications Communicating from Space: The Front End of Multiscale Modeling Laser-Based System Could Expand Space-to-Ground Communication Hydraulic Testing of Polymer Matrix Composite 102mm Tube Section Research could lead to development of a composite material that can be processed at a low temperature and still be used at 1000°F. Permeation Tests on Polypropylene Fiber Materials Study attempts to determine if polypropylene nanofiber materials can be used in air filtration systems to remove toxic vapors. Inter-Laboratory Combat Helmet Blunt Impact Test Method Comparison Ensuring consistent test methods could reduce the risk of head injuries.
Magazine

Tech Briefs: May 2018

2018-05-01
New Technologies Tackle UAV Challenges Robotic Applique Kits Leverage Existing Assets Educating UGVs Implementing AI Advancements in Thermal Image Training Data Sets Protecting Critical Data on Unmanned Underwater Platforms Advancements Made to the Wingman Software-in-the-Loop (SIL) Simulation: How to Operate the SIL New features include the creation of virtual environments that match real-world gunnery test courses. Soldier-Robot Team Communication: An Investigation of Exogenous Orienting Visual Display Cues and Robot Reporting Preferences The effective use of robots to conduct dangerous missions depends on accurate man-machine communications. Soft Robotic Fish Swims Alongside Real Ones in Coral Reefs GPS Enabled Semi-Autonomous Robot Combining GPS signals with acoustic and encoder data gives a robot the ability to determine its location and orientation within a reference frame.
Technical Paper

Computing Remaining Fatigue Life Under Incrementally Updated Loading Histories

2018-04-03
2018-01-0623
After manufacture, every military vehicle experiences a unique history of dynamic loads, depending on loads carried, missions completed, etc. Damage accumulates in vehicle structures and components accordingly, leading eventually to failures that can be difficult to anticipate, and to unpredictable consequences for mission objectives. The advent of simulation-based fatigue life prediction tools opens a path to Digital Twin based solutions for tracking damage, and for gaining control over vehicle reliability. An incremental damage updating feature has now been implemented in the Endurica CL fatigue solver with the aim of supporting such applications for elastomer components. The incremental updating feature is demonstrated via the example of a simple transmission mount component. The damage state of the mount is computed as it progresses towards failure under a series of typical loading histories.
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