Готові списки джерел за темами / Military helicopters Testing

Добірка наукової літератури з теми "Military helicopters Testing"

Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 29 січня 2023

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Статті в журналах з теми "Military helicopters Testing"

Davidson, Gary, Tim Roberts, and Darren Savoye. "Skid Helicopters on High-Speed Craft." Journal of Ship Production 21, no. 02 (May 1, 2005): 108–25. http://dx.doi.org/10.5957/jsp.2005.21.2.108.

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Helicopter decks are common throughout the commercial and military shipping industries and also the offshore industry. Construction in steel and aluminum is common. Helicopter decks on high-speed craft are not common. The first known helicopter deck installed on a high-speed craft was on an Incat wave-piercing catamaran, HSV X1, Joint Venture, which saw service during the recent Gulf war and is currently still in service with the US Army. Following successful construction and NAVAIR certification of Joint Venture, a more advanced aluminum deck, certified also by NAVAIR and Naval Sea Systems Command (NAVSEA), has been fitted to HSV 2 Swift, which is the latest Incat 98 meter "SeaFrame" HSC. HSV 2 Swift is in service with the US Navy. This paper will focus on the design challenge that came about on HSV 2 Swift in the design of the deck to land and park skid type helicopters as opposed to a helicopter with pneumatic tires. High-speed craft are by their nature innovative, and new solutions to old problems are constantly being experimented with to ensure that the tenets of high speed and high efficiency are optimized. Weight minimization is the most critical performance aspect of a high-speed craft, and conservative or simplified analysis is not practical or economic. A high-speed craft relies on accelerating through hump or critical speed to obtain the high operating speeds of around 40 knots and greater. The ability to operate above hump speed is absolutely reliant on the weight of the vessel. Unnecessary weight on the vessel that does not have absolute mission or operation justification adversely affects the ability to operate above hump speed. Aluminum creates additional and very different challenges compared to a design in traditional steel. Alternative details and construction techniques are required for successful design in aluminum in terms of fatigue and ultimate strength. One innovation common in high-speed craft is aluminum extrusion of a top hat form. The top hat offers big savings in terms of ultimate strength and reduction in mass while keeping weight to a minimum. To aid in verifying the design of the Helo deck extrusion on HSV 2 Swift (Incat Yard 061) for the AH-1 and UH-1 helicopters (H-1 series skid type helicopters), analysis and physical testing were carried out. There had been some doubt that conventional hand calculations were suitable for a top hat style extrusion. The analysis and testing proved that extruded aluminum sections of top hat design are suitable for the H-1 series helicopter skid loading and that permanent deformation was negligible at the design load and even at significantly above the design load. The physical test is also further evidence to support the use of welded 6000 series extrusion in high-speed military vessels. Original design of the deck extrusion revolved around class rules, linear static finite element analysis (FEA), and military codes. Later analysis involved nonlinear FEA, further military code calculations, first principles hand calculations based on available text, and physical testing.

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Kulba, P., V. Fedenko, O. Cherednikov, V. Chupryna, and O. Pankul. "TAKING INTO ACCOUNT THE REQUIREMENTS OF EUROPEAN CRITERIA FOR CERTIFICATION OF AIRWORTHINESS OF AIRCRAFT IN TECHNIQUES FOR TESTING THE FLIGHT-TECHNICAL CHARACTERISTICS OF HELICOPTERS." Наукові праці Державного науково-дослідного інституту випробувань і сертифікації озброєння та військової техніки, no. 10 (December 30, 2021): 108–16. http://dx.doi.org/10.37701/dndivsovt.10.2021.12.

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The article considers the problem of improving the methods of testing to determine the flight characteristics of helicopters, taking into account the requirements of European criteria for certification of airworthiness of military aircraft. To ensure interoperability with NATO standards, new standard methods for obtaining and evaluating the flight performance of helicopters have been developed. On the example of determining fuel consumption in assessing the range and duration of the flight considered the basic principles of development of advanced standard techniques. The test methods are based on the use of experimental planning theory using first- and second-order plans. Based on the mathematical theory of experimental planning, regression models of flight technical characteristics of helicopters are compiled and all coefficients of these models are determined. On the basis of the received regression models flight technical characteristics in all range of the used parameters of flights of helicopters of various categories, types and models are calculated. For example, the results of nomogram calculations for determining the kilometer fuel consumption of a helicopter while flying at different speeds in different altitude and climatic conditions are presented. The use of modeling provides increased reliability and accuracy in determining the flight characteristics of helicopters and significantly reduces the cost of testing. Developed advanced techniques, which are adapted to European standards, allow to cover all customer requirements, ie to determine and assess the flight characteristics of helicopters according to the requirements of both national and foreign customers.

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Televnyi, I. "INVESTIGATION OF THE INFLUENCE OF THE INSTALLATION OF THE EXHAUST DEVICE ON THE FLIGHT AND TECHNICAL CHARACTERISTICS OF THE HELICOPTER МИ-24". Наукові праці Державного науково-дослідного інституту випробувань і сертифікації озброєння та військової техніки, № 10 (30 грудня 2021): 172–79. http://dx.doi.org/10.37701/dndivsovt.10.2021.18.

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The article considers the results of installation of exhaust devices on the helicopter. According to the test results, the installation of screen and exhaust devices on the helicopter reduces its thermal visibility, but at the time affects the change in its flight and technical characteristics. Thus, conducting the test of the helicopter Ми-24 with the installed “Adros” screen and exhaust devices АШ-01В the characteristics of the load capacity, height gain of the practical ceiling, maximum flight speeds, stability and handling of the helicopter are investigated. When performing flight tests, most of them are occupied by flight studies for the study of flight and technical characteristics (LTC) of helicopters. Since the installation of screen and exhaust devices on the helicopter affects the change in its flight and technical characteristics, the assessment of the change of the LTC helicopter is mandatory. Methods and methods of flight studies on the evaluation of LTD were based on the works of V.S.Vedrov, A.P.P roskuryakov, M.L.Milya, G.S.Kalachov, L.M.Berestov, A.I.Akimov. Flight research is the main scientific activity of the State Scientific Research Institute for Testing and Certification of Weapons and Military Equipment and during modernizations, the development of various new weapons and equipment is an important scientific problem.

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Lisiecki, Janusz, Dominik Nowakowski, and Piotr Reymer. "Fatigue Properties of Polyurethane Foams, with Special Emphasis on Auxetic Foams, Used for Helicopter Pilot Seat Cushion Inserts." Fatigue of Aircraft Structures 2014, no. 6 (June 1, 2014): 72–78. http://dx.doi.org/10.1515/fas-2014-0006.

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Abstract Seat cushion inserts in military helicopters crew seats, as suggested by the helicopters manufacturers, are made of traditional polyurethane foams. Elastic polyurethane auxetic foams are materials that exhibit different utility properties compared to traditionally used polyurethane foams, such as polyether or polystyrene foams. All the differences result from the primary physical property of elastic polyurethane auxetic foams which is a negative Poisson’s ratio. Auxetic materials are characterized by better utility properties than conventional foam materials – they can potentially increase safety in the event of a crash and offer higher comfort during regular use. Application of auxetic materials as seat cushion inserts would also decrease harmful health effects of vibrations. This paper presents the results of the fatigue tests carried out on different foam samples by pressing an indenter into the foams' surface that was much larger than the indenter’s surface. A maximum value of the load used during the test was within a defined range in every fatigue cycle. In order to test 150×150×50 mm foam samples a special indenter was designed and manufactured according to the PN-EN ISO 3385 and PN-EN ISO 2439 standards. The indenter’s dimensions were consistent with the standards in relation to the tested foams' size. The fatigue tests of both conventional and auxetic foams were carried out according to the above given standards by applying 80,000 load cycles at 70 cycle/min frequency. Tests of viscoelastic foam and multilayer foam specimens, for which the upper layer was made of viscoelastic foam, were carried out according to the ASTM D 3574 standard applying 12,000 load cycles at 10 cycle/min frequency. All the tests were carried out using the MTS 370.10 strength testing machine. Changes in thickness and density were determined throughout the tests. Moreover, the influence of the volumetric compression ratio on the fatigue properties of auxetic foam samples and the dependence of foam deflection on the number of cycles were examined. Finally, the test results obtained for conventional and auxetic foams were compared and discussed.

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Wang, J., and A. Baker. "Aspects of battle damage repair of helicopter structures." Aeronautical Journal 114, no. 1155 (May 2010): 321–32. http://dx.doi.org/10.1017/s0001924000003778.

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Abstract This paper summarises recent research conducted at the Defence Science and Technology Organisation in the area of aircraft battle damage repair, covering aspects such as ballistic testing, ballistic damage prediction, non-destructive damage inspection, structure residual-strength assessment, repair materials and techniques, repair design approaches, repair implementation and demonstration. The research has been focused on military helicopter composite structures. This paper provides an overview of a wide range of research conducted and detailed information in selected areas. Considerations for future research directions are also briefly discussed.

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Wang, J., A. A. Baker, and D. Bitton. "Riveted patch repairs for helicopter tail drive shafts with battle damage." Aeronautical Journal 118, no. 1205 (July 2014): 811–27. http://dx.doi.org/10.1017/s0001924000009556.

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Abstract The ability to repair battle damage in a helicopter tail drive shaft (TDS) caused by small arms fire is a very important capability. A successful repair will enable the helicopter to continue its mission or at least allow it to return safely to base. This paper describes assessment of conventional and novel repair techniques using riveted metallic patches to restore the balance and strength of a damaged TDS. Analytical approaches are provided for the design of the repair. Modal analyses indicated that the effect of repair on change of the natural frequency of the TDS was negligible. An experimental testing program was conducted to validate the proposed repair methods. It has been demonstrated that the proposed repair methods achieved sufficient balance restoration by a defined repair procedure, assuming the unbalance could not be measured during a repair in the field. The conventional thin, single aluminium sheet, riveted repair significantly restored static strength. However, it only gave a fatigue life of 15hrs, and thus the repaired shaft may only be used for limited time for a military mission. The improved thick, two-half aluminium shell, riveted repair had sufficient static strength and met the 100-hour fatigue requirement.

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Norii, T., Y. Terasaka, M. Miura, T. Nishinaka, R. Lueken, H. Sasaki, and A. Alseidi. "(P1-9) Multinational Disaster Response Exercise: Critical Look and Lessons Learned." Prehospital and Disaster Medicine 26, S1 (May 2011): s101. http://dx.doi.org/10.1017/s1049023x11003414.

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IntroductionInternational collaboration for disaster response is an increasing phenomenon. Japan-United States joint field exercises have been conducted annually since 2004, triggered by an incident in which a US helicopter crashed into a university campus in Okinawa, Japan. The fifth Japan-US disaster field exercise was conducted testing the disaster response of the Okinawa government and US military.MethodsThe simulated exercise involved a US Navy aircraft that crashed into a city center in Okinawa, Japan. There were 16 simulated casualties that included US military members and Japanese citizens. The participants in this exercise were US military members, including the Disaster Assistance Response Team (DART) and local rescue and medical teams including the Okinawa Disaster Medical Assistance Team (DMAT). Data were gathered from the joint debriefing session held by both medical teams. Furthermore, interviews with team leaders from both nations were conducted and feedback obtained.ResultsLack of communication and inaccurate communication remained the root of most problems encountered. There were several miscommunications at the scene due to the language barrier and ignorance of different medical teams' capability and method of practice. Due to the unclear signage of the initial triage zone, another triage zone was developed later by a second medical team. Confusion regarding gathering information and order of transport also was witnessed. The capabilities of team members were not well known between teams, resulting in inappropriate expectations and difficulty in effective cooperation.ConclusionsUnderstanding the systems and backgrounds of each medical team is essential. Signs or symbols of key elements including triage areas should be clear, universal, and multilingual. Communication remains the Achilles' heel of multi-national disaster response activities.

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Kim, Tae-Uk, JeongWoo Shin, and Sang Wook Lee. "Design and Testing of a Crashworthy Landing Gear." ASCE-ASME J Risk and Uncert in Engrg Sys Part B Mech Engrg 3, no. 4 (June 22, 2017). http://dx.doi.org/10.1115/1.4036663.

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The development of a crashworthy landing gear is presented based on the civil regulations and the military specifications. For this, two representative crashworthy requirements are applied to helicopter landing gear design: the nose gear is designed to collapse in a controlled manner so that it does not penetrate the cabin and cause secondary hazards, and the main gear has to absorb energy as much as possible in crash case to decelerate the aircraft. To satisfy the requirements, the collapse mechanism triggered by shear-pin failure and the shock absorber using blow-off valve (BOV) is implemented in the nose and main gear, respectively. The crash performance of landing gear is demonstrated by drop tests. In the tests, performance data such as ground reaction loads and shock absorber stroke are measured and crash behaviors are recorded by high-speed camera. The test data show a good agreement with the prediction by simulation model, which proves the validity of the design and analysis.

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McMurray, Haana, Laura S. Kraemer, Edward Jaffe, Sorana Raiciulescu, Julia M. Switzer, Gerardo Capo Dosal, Rachael Dampman, Theepica Jeyarajah, Joseph Lopreiato, and Mark W. Bowyer. "Development of a Simulation Surgical Cricothyroidotomy Curriculum for Novice Providers: A Learning Curve Study." Military Medicine, December 24, 2021. http://dx.doi.org/10.1093/milmed/usab520.

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ABSTRACT Introduction Airway obstruction is the third most common cause of preventable death on the battlefield, accounting for 1%–2% of total combat fatalities. No previous surgical cricothyroidotomy (SC) studies have analyzed the learning curve required to obtain proficiency despite being studied in numerous other surgical technique training experiments. The aims of this study were to establish expert SC performance criteria, develop a novel standardized SC curriculum, and determine the necessary number of practice iterations required by a novice to reach this pre-determined performance goal. Materials and Methods A standardized checklist and SC performance standards were established based on the performance of 12 board certified Military Health System surgeons with prior experience on performing a SC using a simulated trauma mannequin. Expert-level criteria were defined as a SC time to completion of 40 s or less and checklist score of at least 9/10, including all critical steps. Study subjects included 89 novice providers (54 active-duty first- and second-year medical students and 35 Navy corpsmen). Subjects received instruction on performing a SC using the principles of mastery learning and performed a final test of SC proficiency on a trauma mannequin within a realistic simulated MEDEVAC helicopter. The total number of subject practice attempts, checklist scores, and time to completion were measured and/or blindly scored. Learning curve and exponential plateau equations were used to characterize their improvement in mean time to SC completion and checklist scores. Results Mean pre-test knowledge scores for the entire group were 11.8 ± 3.1 out of 24 points. Total mean practice learning plateaued at checklist scores of 9.9/10 after 7 iterations and at a mean completion time of 30.4 s after 10 iterations. During the final test performance in the helicopter, 67.4% of subjects achieved expert-level performance on the first attempt. All subjects achieved expert-level performance by the end of two additional attempts. While a significantly larger proportion of medical students (79.9%) successfully completed the helicopter test on the first attempt compared to corpsmen (54.3%), there were no statistically significant differences in mean SC completion times and checklist scores between both groups (P > 0.05). Medical students performed a SC only 1.3 s faster and scored only 0.16 points higher than corpsmen. The effect size for differences were small to negligible (Cohen’s d range 0.18–0.33 for SC completion time; Cohen’s d range 0.45–0.46 for checklist scores). Conclusion This study successfully defined SC checklist scores and completion times based on the performance of experienced surgeons on a simulator. Using these criteria and the principles of mastery learning, novices with little knowledge and experience in SC were successfully trained to the level of experienced providers. All subjects met performance targets after training and overall performance plateaued after approximately seven iterations. Over two-thirds of subjects achieved the performance target on the first testing attempt in a simulated helicopter environment. Performance was comparable between medical student and corpsmen subgroups. Further research will assess the durability of maintaining SC skills and the timing for introducing refresher courses after initial skill acquisition.

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Дисертації з теми "Military helicopters Testing"

Revor, Mark S. "An analysis of the integrated mechanical diagnostics health and usage management system on rotor track and balance." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FRevor.pdf.

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Thesis (M.S. in Operations Research)--Naval Postgraduate School, June 2004.
Thesis advisor(s): Lyn R. Whitaker, Arnold H. Buss. Includes bibliographical references (p. 77-78). Also available online.

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Книги з теми "Military helicopters Testing"

Office, General Accounting. Comanche helicopter: Testing needs to be completed prior to production decisions : report to congressional committees. Washington, D.C: The Office, 1995.

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Office, General Accounting. Weapon systems: Shortfalls in automatic fault diagnosis : report to the Secretary of the Army. Washington, D.C: The Office, 1987.

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Office, General Accounting. Weapon systems: Effects of Army decision to reduce helicopter procurement : briefing report to the Honorable Dennis DeConcini, United States Senate. Washington, D.C: The Office, 1987.

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Office, General Accounting. Electronic warfare: Most Air Force ALQ-135 jammers procured without operational testing : report to congressional requesters. Washington, D.C: The Office, 1994.

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Office, General Accounting. Electronic warfare: Phased approach to infrared upgrades would reduce risk to helicopters : report to the chairman, Subcommittee on Military Research and Development, Committee on Armed Services, House of Representatives. Washington, D.C. (P.O. Box 37050, Washington, D.C. 20013): The Office, 2000.

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Office, General Accounting. Electronic warfare: Need to strengthen controls over Air Force jammer programs : report to the chairman, Committee on Armed Services, House of Representatives. Washington, D.C: The Office, 1990.

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Office, General Accounting. Electronic warfare: Comprehensive strategy needed for suppressing enemy air defenses : report to congressional requesters. Washington, D.C. (P.O. Box 37050, Washington 20013): U.S. General Accounting Office, 2001.

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Office, General Accounting. Electronic warfare: The Army can reduce its risks in developing new radar countermeasures system : report to the Secretary of Defense. Washington, D.C. (P.O. Box 37050, Washington 20013): U.S. General Accounting Office, 2001.

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Більше джерел

Частини книг з теми "Military helicopters Testing"

M. Skip Scheifele, Peter, Devan Marshall, Stephen Lee, Paul Reid, Thomas McCreery, and David Byrne. "Canine Hearing Management." In Veterinary Medicine and Science. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105515.

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The United States military employs multipurpose canines as force multipliers. A newly developed baseline audiology program applicable to noise effects on the hearing threshold for these dogs has just been developed by the University of Cincinnati FETCHLAB using brainstem auditory evoked potentials to detect estimated threshold shifts in this population. Dogs that are routinely deployed are subject to consistent exposure to noise in the field. Few investigations have focused on the effects of transport noise on the auditory system in multipurpose dogs. The consequence of these dogs having a significant hearing threshold shift is a failure of the dog to properly respond to voice commands and to miss critical acoustic cues while on target. This chapter specifically discusses the baseline protocol for audiological testing of special operations’ multipurpose canines related to helicopter transport.

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Тези доповідей конференцій з теми "Military helicopters Testing"

Bartie, Kenneth. "History of the Vertol Aircraft Corporation, 1956 to 1960." In Vertical Flight Society 77th Annual Forum & Technology Display. The Vertical Flight Society, 2021. http://dx.doi.org/10.4050/f-0077-2021-16811.

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With an overall company lifespan of only four years, Vertol Aircraft Corporation continued the tandem-rotor helicopter legacy of its predecessor, Piasecki Helicopter Corp., as well as research, development and testing of other V/STOL aircraft and technologies while concurrently designing two medium-lift transport helicopters that are still in worldwide use and/or production today. During this short timeframe, the company finalized production and deliveries of the H-21C Shawnee/V-44 for the US Army and international customers. The company designed and flew the world’s first tilt-wing VTOL, the NACA/Army/Navy/Vertol VZ-2A. Application of T53 and T58 turbine powerplants led to twin-turbine engine trials and flight tests with experimental H-21 variants. With Vertol’s in-theater customer support, the French Army and Navy introduced the H-21 into combat in Algeria which included the early use of armed, troop-carrying helicopters. The design, test and successful US and worldwide demonstrations of the privately-funded Vertol 107 led to development and certification of the 107-II airliner version and follow-on military transports as the Boeing H-46 Sea Knight. The contract to design and build the YHC-1B was won by Vertol in 1959 and led to the enduring Boeing H-47 Chinook.

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Colvin, David P., and Richard A. McKinney. "Reduction in Body Vibration and Spinal Impact With HACS Cushioning." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-82911.

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High vibration and impact injuries continue to cause problems for military and civilian personnel in aircraft, trucks and armored vehicles. Crashes in helicopters and fixed wing aircraft as well as repetitive impacts in armored vehicles and trucks over rough terrain can pose serious problems and potential injuries for their occupants. Protective seat cushions can be engineered to absorb or mitigate a significant fraction of the mechanical energy before it is transmitted to the body. It has been shown, however, that conventional foam seat cushions can actually increase the potential for injury by allowing the body accelerations to overshoot. On the other hand, new and novel designs for cushioning materials can significantly reduce the potential for injuries from whole body vibration as well as spinal impact by extending and altering the duration of the high energy mechanical pulse. Based on unique computer models and subsequent CAD/CAM designs, prototype HACS seat cushions were fabricated from elastomers of three different durometers that incorporated precision, lateral choked airflow passages molded into the cushioning material. Subsequent testing with the NAVY Crew System Horizontal Accelerator at Patuxent River Naval Air Station, MD showed that the novel HACS seat cushion was 40% more effective than any other conventional aircraft seat cushion for the reduction of lumbar spinal load transmission to crash test dummies of all sizes during 23g impact tests. In more recent testing for the AAAV armored vehicle program, HACS seat cushioning has been shown to reduce whole body vibration by 36%.

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Kim, Tae-Uk, JeongWoo Shin, and Sang Wook Lee. "Design and Testing of a Crashworthy Landing Gear." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-52474.

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The development of a crashworthy landing gear is presented based on the civil regulations and the military specifications. For this, two representative crashworthy requirements are applied to helicopter landing gear design; the nose gear is designed to collapse in a controlled manner so that it does not penetrate the cabin and cause secondary hazards, and the main gear has to absorb energy as much as possible in crash case to decelerate the aircraft. To satisfy the requirements, the collapse mechanism triggered by shear-pin failure and the shock absorber using blow-off valve are implemented in the nose and main gear, respectively. The crash performance of landing gear is demonstrated by drop tests. In the tests, performance data such as ground reaction loads and shock absorber stroke are measured and crash behaviors are recorded by high-speed camera. The test data shows a good agreement with the prediction by simulation model, which proves the validity of the design and analysis.

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Stemper, Brian D., Narayan Yoganandan, Jamie L. Baisden, Frank A. Pintar, and Barry S. Shender. "Rate-Dependent Failure Characteristics of Thoraco-Lumbar Vertebrae: Application to the Military Environment." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80139.

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Quantification of lumbar spine vertebral body tolerance to axial compressive loads is important to understand the biomechanics of injury and for the development of safety enhancements. While fracture tolerance for isolated lumbar vertebral bodies has been outlined in multiple experimental studies, compressive rates were generally in the quasi-static range (e.g., 5 mm/min) [1–4]. However, vertebral body fractures most commonly occur under dynamic mechanisms such as falls from height. In the military environment, lumbar fractures were demonstrated following aviator ejection, helicopter crashes, and underbody blast events involving improvised explosive devices. Vertebral body compression during those events is likely to be orders of magnitude greater than quasi-static rates used previously [5]. Due to the loading rate dependence demonstrated for other tissues, including thoracic vertebrae [6], arteries [7], ligaments [8], and isolated spines [9], tolerance limits obtained from quasi-static testing are not likely applicable for the dynamic loading environment. Therefore, this study was conducted to quantify dynamic fracture biomechanics of lumbar vertebrae.

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Kendall, Cory, and Greg R. Doud. "Characterizing Tensile Strength Properties in an E-Glass Composite With Fiber Waviness." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63631.

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This report investigates failure properties of a unidirectional fiber-reinforced E-glass epoxy resin matrix (CYCOM 5216). This material is used in military and commercial helicopter blades and structures and is commonly used in engine nacelles. Testing and failure analysis is critical for these structures, which undergo vibratory and complex aerodynamic loading. Defined manufacturing methods were modified to produce thick samples containing wrinkle defects. Wrinkles were added to simulate realistic marcelling, which commonly occurs within complex structures. All samples were validated using volume fraction experiments. Static uniaxial tension and five-point bending testing was performed as strain was measured using a multi-axis strain gage or an axial extensometer. Tensile and shear moduli, tensile strength, and shear strength were all determined. Shear modulus was determined through the use of a reinforced five point bending apparatus. The effects of fiber waviness on static strength were observed by testing samples with wrinkles of varying amplitude in both shear and tension. Fatigue analysis in this study differs from previous finite element crack growth studies due to the introduction of fiber waviness. For this reason, previous mixed mode bending tests and analytical methods were used with finite element techniques to improve failure prediction methods.

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Douglas, Laura M. "Development of a Lubrication System for the T800-LHT-800 Turboshaft Engine." In ASME 1991 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/91-gt-398.

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The T800-LHT-800 is a modern technology 1300 shp (975 kW) class turboshaft engine developed for the U.S. Army’s LH helicopter which has great potential for application in various civil air vehicles. As one of its significant features, the engine has a self-contained dry sump, pressure and temperature regulated, recirculating lubrication system. Contractually specified operational attitude and loss of oil requirements impose considerable complications on the design/development of the T800’s lubrication system. Characteristically, lubrication systems provide cooling and lubrication to all bearings, gears, seal rotors, and working splines at all engine operating conditions. The T800-LHT-800 lubrication system must provide continuous lubrication for an engine operational attitude envelope range of 120 deg noseup, 90 deg nosedown, and 48 deg rolls in either direction. Development of the lubrication system attitude capabilities has been accomplished via testing on a lubrication simulator rig and a series of both development and qualification engine attitude tests. A formal engine attitude qualification test, which will demonstrate both military qualification test (QT) and civil (FAA) certification requirements, will be conducted in 1991. Contractually required engine protection against loss of oil conditions lasting up to six min provided a significant design challenge for the T800 lubrication system and an emergency oil system was designed to meet this requirement. This emergency oil system was developed via multiple design iterations, bench testing on a lubrication simulator rig, and loss of oil development engine testing. As part of the qualification process, a formal qualification loss of oil engine test will be conducted in mid-1991 to verify this design capability. This paper describes the basic T800 engine and discusses the lubrication system requirements. It emphasizes the design evolution of the main oil tank attitude capabilities, the emergency oil system, and the planned qualification/certification testing.

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Ames, Eric C., and Raja V. Pulikollu. "Virtual Life and Performance Modeling of Aerospace Spiral Bevel Gears." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-12351.

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Spiral bevel gears are widely used in the tail rotor drive trains of most rotorcraft. The loads associated with the tail rotor drive train are generally much more variable than those in the main rotor drive train primarily resulting from maneuvers. Over the life of any particular military rotorcraft it is not uncommon for the aircraft’s operating gross weight to steadily increase, causing the aircraft to fly at higher mean power levels and thus increasing the operating load spectrum associated with the tail rotor drive train. Special missions and equipment such as pulling a mine sweeping sled or very high altitude high gross weight assaults can put severe load demands on the tail drive train. This paper details an effort conducted to evaluate the effects of short to moderate duration overloads on the spiral bevel gears of the UH-60 helicopter tail rotor drive train. The focus of the effort was on the Tail Take-off gear mesh (TTO). An initial analytical assessment of the effect of loads above the endurance limit was conducted using an American Gear Manufacturers Association (AGMA) based approach. To confirm the validity of this approach, overload testing of the TTO gear mesh was conducted by the U.S. Army’s Aviation Applied Technology Directorate at the Navy’s test facility in Paxtuent River MD. Following the testing, the gear tooth bending and surface fatigue lives were analyzed using a microstructure based probabilistic tool developed by Sentient Corporation. The tool, known as Digital Clone was able to run hundreds of virtual tests that closely simulated the actual testing thus providing a low cost method for increasing the confidence associated with the effects of short to moderate high transient loads.

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Benson, Michael J., Bret P. Van Poppel, Daisie D. Boettner, and A. O¨zer Arnas. "A Virtual Gas Turbine Laboratory for an Undergraduate Thermodynamics Course." In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53489.

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Topics on gas turbine machinery have been successfully integrated into the thermodynamics course at the United States Military Academy (USMA). Because graduating cadets will encounter gas turbines throughout their service in the U.S. Army, it is important for all engineering students, not just mechanical engineering majors, to learn about gas turbines, their operation, and their applications. This is accomplished by four methods, one of which is an experimental analysis of an operational auxiliary power unit (APU) from an Army helicopter. Due to recent building issues, this gas turbine laboratory was improvised and offered as a fully digital virtual laboratory exercise. Since all undergraduate programs do not have the luxury of having a gas turbine laboratory, our experiences with the virtual laboratory are offered as an effective option. By digitally reproducing the laboratory setup, introduction, instrumentation, data collection and analysis, the virtual experience captures the essence of the laboratory. After viewing the web-based laboratory digital media files, students use one of two data sets, recorded from the data display panel in the real laboratory, in order to complete the laboratory report. While the tremendous advantage of actually seeing, testing, and analyzing the real engine cannot be denied, a well-planned and executed virtual laboratory adequately achieves learning objectives and provides students a unique opportunity to apply gas turbine fundamentals. An assessment of the virtual laboratory and results of student feedback are provided.

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Lee, Zachary, Shane Lowe, Bret P. Van Poppel, Michael J. Benson, and Aaron St. Leger. "Upgrading the Undergraduate Gas Turbine Lab." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25943.

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A study of gas turbine engines is an important component of an integrated thermodynamics and fluid mechanics two-course sequence at the United States Military Academy (USMA). Owing to the ubiquity of gas turbines in military use, graduating cadets will encounter a variety of these engines throughout their military careers. Especially for this unique population, it is important for engineering students to be familiar with the operation and applications of gas turbines. Experimental analysis of a functional auxiliary power unit (APU) from an Army utility helicopter has been a key component of this block of instruction for several decades. As with all laboratory equipment, the APU has experienced intermittent maintenance issues, which occasionally render it unusable for the gas turbine laboratory in the course. Because of this, a very basic virtual laboratory was implemented which integrated video of the physical laboratory with key parameters and behind-the-screen data collection for use in engine analysis. A revitalized version of both the physical and virtual gas turbine laboratory experiences offered in the thermal-fluids course will include substantial improvements over the existing setup. The physical laboratory, which is centered on a refurbished APU from a medium-sized commercial aircraft, will continue to incorporate measurements of temperature and pressure throughout the combustion process, as well as fuel flow rate. In an improvement over the original laboratory setup, an orifice plate will be used to measure the flow rate of bleed air exiting the turbine, which had not previously been open during engine testing. Additionally, the air flow through the anti-surge valve was not metered in the original version of the physical laboratory. However, the anti-surge air flow can account for nearly 25% of the total air flow, and performance calculations in the physical laboratory will now account for this loss. The turbine output shaft will run a water-brake dynamometer. All instrumentation will be converted to digital signals and projected on a large screen outside the test area through a LabVIEW front panel. The virtual laboratory will include the same metering options as the operational APU. In addition, the virtual laboratory will include the option to alter engine operating parameters, such as inlet temperature and pressure or exhaust temperatures, and students may conduct broad parameter sweeps across ranges of possible inputs or desired outputs. These improvements will enable students to gain a deeper understanding of gas turbine operation and capabilities in practical applications. The improved laboratory will be implemented in Spring, 2014.

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