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Viewing 61 to 90 of 19997
2017-09-19
Technical Paper
2017-01-2141
Fengmei Li, Peng Ke
Abstract For the ice protection of the engine air induction part manufactured with low thermal conductivity composite material, the combined heating method using interior impingement and exterior air film has certain advantages. To study the influence of the external jet air film on the impingement characteristics of droplets, the numerical simulation method of three dimensional water droplet impingement based on Eulerian method was developed and verified by experimental data from references. The droplets impingement characteristics under three different blowing ratios and two different velocities were then investigated based on the configuration of 3D cylinder with two parallel jet holes.
2017-09-19
Journal Article
2017-01-2018
Won Il Jung, Larry Lowe, Luis Rabelo, Gene Lee, Ojeong Kwon
Operator training using a real weapon in a real-world environment is risky, expensive, time-consuming, and restricted to the given environment. The simulator, or a virtual simulation, is usually employed to solve these limitations. As the operator is trained to maximize weapon effectiveness, the effectiveness-focused training can be completed. However, the training was completed in limited scenarios without guidelines to optimize the weapon effectiveness for an individual operator, thus the training will not be effective with a bias. For overcoming this problem, we suggest a methodology on guiding effectiveness-focused training of the weapon operator using big data and Virtual and Constructive (VC) simulations. Big data, which includes structured, unstructured, and semi-structured types, are generated by VC simulations under a variety of scenarios.
2017-09-19
Technical Paper
2017-01-2019
Rakshath G Poojary, Mohammed Ali Jouhar, Abubakar K
Human Powered Helicopter which uses man power to operate. The main aim of this paper is to design commercially available vehicle for an Adventure Sporting under 5-6 lakh Indian Rupees. This structural design is extremely lightweight and strong. The product is designed in such a way that it can be easily assembled and dismantled for transportability and storage. We developed an aero-structural optimization scheme for rotor design, including an aerodynamic model with included ground effect prediction, finite-element analysis and integrated composite failure analysis, and a detailed weight estimation scheme. This was solely build on computer CAD models. This design includes the use of gear box to increase the output. The Aerodynamic analysis was done using CFD and BET (blade element theory-Bhramwell) in MATLAB.
2017-09-19
Journal Article
2017-01-2024
Natasha L. Schatzman, Narayanan Komerath, Ethan A. Romander
The blade crossing event of a coaxial counter-rotating rotor is a potential source of noise and impulsive blade loads. Blade crossings occur many times during each rotor revolution. In previous research by the authors, this phenomenon was analyzed by simulating two airfoils passing each other at specified speeds and vertical separation distances, using the compressible Navier-Stokes solver OVERFLOW. The simulations explored mutual aerodynamic interactions associated with thickness, circulation, and compressibility effects. Results revealed the complex nature of the aerodynamic impulses generated by upper/lower airfoil interactions. In this paper, the coaxial rotor system is simulated using two trains of airfoils, vertically offset, and traveling in opposite directions. The simulation represents multiple blade crossings in a rotor revolution by specifying horizontal distances between each airfoil in the train based on the circumferential distance between blade tips.
2017-09-19
Technical Paper
2017-01-2026
Narayanan Komerath, Shravan Hariharan, Dhwanil Shukla, Sahaj Patel, Vishnu Rajendran, Emily Hale
Our concept studies have indicated that a set of reflectors floated at high altitudes and supported by aerodynamic lift, can reduce radiant forcing into the atmosphere. The cost of reducing the radiant forcing sufficiently to reverse the current rate of global warming, is well within the financial abilities of the world. This paper describes one of the concepts for such reflectors. The basic element of a reflector array is a rigidized reflector sheet towed behind and above a solar-powered, distributed electric-propelled fixed flying wing aircraft. The altitude rises above 30,480 meters (100,000 feet) in the daytime and does not sink below 28,288 meters (60,000 feet or Flight Level FL60) at night. While the reflector sheet easily supports its own weight with very small lift coefficient, the skin friction and induced drag components are large.
2017-09-19
Technical Paper
2017-01-2047
Tyler Vincent, Joseph Schetz, K. Lowe
Analysis and design of total temperature probes for accurate measurements in hot, high-speed flows remains a topic of great interest in aerospace propulsion and a number of other engineering areas. Despite an extensive prior literature on the subject, prediction of error sources from convection, conduction and radiation is still an area of great concern. For hot-flow conditions, the probe is normally mounted in a cooled support, leading to substantial axial conduction along the length of the probe. Also, radiation plays a very important role in most hot, high-speed conditions. One can apply detailed computational methods for simultaneous convection, conduction and radiation heat transfer, but such approaches are not suitable for rapid, routine analysis and design studies. So, there is still a place for approximate methods, and that is the subject of this paper.
2017-09-19
Technical Paper
2017-01-2052
K Friedman, G Mattos, K Bui, J Hutchinson, A Jafri, J Paver PhD
Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropometric dummies such as those outlined in 14 CFR part 25. An example would be a dummy seated in an upright position held with a two point belt decelerated from an impact speed and allowed to engage components that are in front of the dummy. Examples of head contact surfaces would include video monitors, a wide range of seat back materials, and airbags from which the HIC and other injury measures can be calculated. Other injury measures, such as Nij, are also of interest and can be measured with the Hybrid III dummy as well. A minimum deceleration pulse is defined as part of the regulations for a frontal impact. In this study the effect of variations in decelerations that meet the requirements is considered.
2017-09-19
Technical Paper
2017-01-2054
K Friedman, G Mattos, K Bui, J Hutchinson, A Jafri, J Paver
Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropometric dummies such as those outlined in 14 CFR part 25. An example would be a dummy seated in an upright position held with a two point belt decelerated from an impact speed and allowed to engage components that are in front of the dummy. Examples of head contact surfaces would include video monitors, a wide range of seat back materials, and airbags from which the HIC and other injury measures can be calculated. Other injury measures, such as Nij, are also of interest and can be measured with the Hybrid III dummy as well. It has been shown that the friction between the head form and contact surfaces can affect the test results obtained in other safety applications.
2017-09-19
Technical Paper
2017-01-2115
Gilberto Burgio, Leonardo Mangeruca, Alberto Ferrari, Marco Carloni, Virgilio Valdivia-Guerrero, Laura Albiol-Tendillo, Parithi Govindaraju, Marcel Gottschall, Olaf Oelsner, Sören Reglitz, Jann-Eve Stavesand, Andreas Himmler, Lionel Yapi
This paper presents a demonstrator implemented in the project MISSION (Modelling and Simulation Tools for Systems Integration on Aircraft). This is a collaborative project being developed under the European Union Clean Sky 2 Program, a public-private partnership bringing together aeronautics industrial leaders and public research organizations based in Europe. The provision of integrated modelling, simulation, and optimization tools to effectively support all stages of aircraft design remains a critical challenge in the aerospace industry. In particular the high level of system integration that is characteristic of new aircraft designs is dramatically increasing the complexity of both design and verification. Simultaneously, the multiphysics interactions between structural, electrical, thermal, and hydraulic components have become more significant as the systems become increasingly interconnected.
2017-09-19
Technical Paper
2017-01-2096
Rainer Mueller, Matthias Vette, Aaron Geenen, Tobias Masiak
Abstract Assembly processes in aircraft production are difficult to automate due to technical risks. Examples of such technical challenges include small batch sizes and large product dimensions as well as limited work space for complex joining processes and organization of the assembly tasks. A fully automated system can be expensive and requires a large amount of programming knowledge. For these reasons, ZeMA believes a semi-automated approach is the most effective means of success for optimizing aircraft production. Many methods can be considered semi automation, one of which is Human-Robot-Collaboration. ZeMA will use the example of a riveting process to measure the advantages of Human-Robot-Collaboration systems in aircraft structure assembly. In the assembly of the aircraft aft section the pressure bulkhead is mounted with a barrel section using hundreds of rivets. This assembly process is a non-ergonomic and burdensome task in which two humans must work cooperatively.
2017-09-19
Technical Paper
2017-01-2030
Benjamin Cheong, Paolo Giangrande, Patrick Wheeler, Pericle Zanchetta, Michael Galea
In effort to reduce environmental impact of the aerospace industry, More Electric Aircraft (MEA) concepts with electrical systems for fuel pumping, wing ice protection, environmental control systems and aircraft actuation are becoming more and more widely researched. The replacement of hydraulic actuators by motor drives for flight control surfaces is particularly attractive for maintainability, reduction in operating costs and to eliminate the hydraulic fluid. High power density of aerospace motor drives is a key factor in the successful realization of these concepts. An integrated system design approach offer optimization opportunities for further improvements in power density however the challenge lies in its multi-disciplinary modelling and the handling of numerous optimization variables or constraints that are discrete and non-linear in nature. A 4-level modelling paradigm has been proposed by multiple authors to represent a motor drive.
2017-09-19
Technical Paper
2017-01-2059
Enrico Cestino, Giacomo Frulla, Renzo Duella, Paolo Piana, Francesco Pennella, Francesco Danzi
Future generations of civil aircrafts and unconventional unmanned configurations demand for innovative structural concepts to obtain the structural performance, and thus reduce the structural weight. For instance, one of the method to improve structural component is the material coupling used to alter static and dynamic aeroelastic stabilities. It is therefore useful to use an accurate and computationally efficient beam model during the preliminary design phase. In the present work, a numerical validation of equivalent homogeneous orthotropic material procedure, described in [1] and [2], is performed by the application of structural topology optimization technique [3] on a box beam made of isotropic material. The overall equivalent bending, torsional and coupled stiffness is derived by means of homogenization of the shell skin and of the stiffener plate stiffness. The optimum theoretical conditions of bending-torsion coupling was obtained when stiffeners were oriented at about 27°.
2017-09-19
Technical Paper
2017-01-2064
Parvez Alam M, Dinesh Manoharan, Satheesh Chandramohan, Sabarish Chakkath, Sunil MAURYA
In the present market, multiple sophisticate and expensive Thrust Test Rigs for Brushless Motors (BLDC Motor) are available making it impossible to conduct such thrust analysis on a regular and cost effective basis. Moreover the present test rigs are incapable to measure high Thrust values. This needs specialized thrust testing rig which is more expensive. This paper aims at Design & Development of the Small Scale Test Rig Setup for measurement of the thrust of any Brushless DC motor and helps in refining the Selection of motor and propeller. This is a set up based on cost efficiency factor to implement such rigs, test and for comparing the static thrust produced by the BLDC motor. The fairly simple construction contains a weighing machine, a Tachometer and a Wattmeter to measure the Thrust, RPM and the Current Drawn respectively, and provide comprehensive, accurate and efficient data coming from the BLDC Motor including the Propeller and Electronic Speed Control (ESC).
2017-09-19
Technical Paper
2017-01-2063
Patrick Browning, Bryan Shambaugh, Joseph Dygert
The dielectric barrier discharge (DBD) has been studied significantly in the past 2 decades for its applications to various aerodynamic problems. The most common aerodynamic applications have been stall/separation control and boundary layer modification. Recently several researchers have proposed utilizing the DBD in various configurations to act as viable propulsion systems for micro and nano aerial vehicles. The DBD produces stable atmospheric-pressure non-thermal plasma in a thin sheet with a preferred direction of flow. The plasma flow, driven by electrohydrodynamic body forces, entrains the quiescent air around it and thus develops into a low speed jet on the order of 10-1 to 101 m/s. Several researchers have utilized DBDs in an annular geometric setup as a propulsion device. Other researchers have used them to alter rectangular duct flows and directional jet devices. This study investigates 2-D duct flows for applications in micro plasma thrusters.
2017-09-19
Technical Paper
2017-01-2062
Tushar Choudhary, Mithilesh Sahu, Shreya KRISHNA
Solid oxide fuel cell (SOFC) is the most promising candidate for utilization of waste generated from the GT based power system. By coupling SOFC with gas turbine (GT) based power system, a hybrid SOFC–GT power system has been developed and the thermal efficiency of the system can be enhanced upto 70-85%. This paper focuses of thermodynamic analysis of an internal reformed solid oxide fuel cell which is integrated with the gas turbine cycle to form a hybrid power generation system for an unmanned aerial vehicle (UAV) with a long range. Thermodynamic 1st and 2nd law, parametric analysis has been carried out and the effect of various parameters such as compressor pressure ratio, turbine inlet temperature, air flow rate has been examined. In order to validate the results, present work has been compared with the available literature and it shows good agreement.
2017-09-19
Technical Paper
2017-01-2061
Andrea Cravana, Gerardo Manfreda, Enrico Cestino, Giacomo Frulla, Robert Carrese, Piergiovanni Marzocca
An accurate aeroelastic assessment of powered HALE aircraft is of paramount importance considering that their behaviour contrasts the one of conventional aircraft mainly due to the use of high aspect-ratio wings with distributed propulsion systems. This particular configuration shows strong dependency of the wing natural frequencies to the propulsion distribution and operating conditions. Numerical and experimental investigations are carried out to better understand the behaviour of flexible wings, focusing on the effect of distributed electric propulsion systems. Several configurations are investigated, including a single propulsion system (composed of the electric motor, propeller, and the wing-propulsion mounting POD) installed at selected spanwise positions, and configurations with two and three propellers. References: Amato, E.,Polsinelli, C.,Cestino, E.,Frulla, G.,Carrese, R.,Marzocca, P. (2016).
2017-09-19
Technical Paper
2017-01-2070
Nicholas Anderson, Joseph Gao, Eric Whitman, Srikanth Gururajan
Recent advances in Small Unmanned Aerial Systems (SUAS) or drone technologies has resulted in their widespread use in a number of civilian applications, such as aerial imaging, infrastructure inspection, precision agriculture, among others. While this technology is accessible for everyone, it still requires a highly skilled operator to be able to successfully operate these drones in a safe and efficient manner. At the same time, the developments in Virtual/Augmented Reality (V/AR) technologies present opportunities for combining the two into novel applications and use cases, while providing an intuitive interface for interacting with the drones – this opens up possibilities for effective use of the drones by relatively untrained operators for civilian and military use.
2017-09-19
Technical Paper
2017-01-2065
Sebastian Bandycki, Michele Trancossi, Jose Pascoa
This paper presents a comparison between different hypotheses of propulsion of a spherical UAS. Different architectures have been analyzed assessing their specific aerodynamic, energetic, and flight mechanics features. The comparison has been performed assuming the robustness of flight control in different wind conditions, defining for each the specific operative ranges, mission profiles, and energy assessment. An effective energy assessment and comparison against a commercial UAS has been produced. Even if the paper considers a preliminary simplified configuration, it demonstrates clearly to be competitive against traditional quadcopters in a predefined reference mission.
2017-09-17
Technical Paper
2017-01-2512
Matteo Corno, Federico Roselli, Luca Onesto, Sergio Savaresi, Frank Molinaro, Eric Graves, Andrew Doubek
Anti-lock braking systems are one of the most important safety systems for wheeled vehicles. They reduce the braking distance and, most importantly, help the user maintain controllability and steerability of the vehicle. This paper extends and adapts the concept of Anti-lock braking systems to tracked vehicles, in particular to snowmobiles. Snowmobiles are an interesting development platform for two main reasons: 1) track dynamics, despite being analogous to tyre dynamics, present important differences that help understanding the features of the control algorithm and 2) snowmobiles are simple and rugged vehicles with a limited set of sensors, making the design of an effective control system challenging. The paper designs a track-deceleration based ABS algorithm and tests it both in straight riding and cornering.
2017-09-17
Technical Paper
2017-01-2505
Mahesh Shridhare, Santosh Sonar, Manish Ranawat, Ajit Kumar Jindal
It is well established that one of the causes of brake pulling during straight ahead braking of the vehicle is torque difference between Left and Right wheel brakes. This paper explains a method to estimate and reduce brake pulling of a Light commercial vehicle (LCV) caused by such a brake torque difference during panic braking. It is challenging to eliminate this unwanted brake pulling in shorter wheelbase LCV having all drum brakes and high center of gravity. A mathematical model is developed to estimate extent of brake pulling from known parameters like brake torque at each wheel, tire properties, steering geometry, vehicle center of gravity location etc. With the help of this model the sensitivity of each parameter change on vehicle pulling derived & it supported for optimizing the DOE. Vehicle tests have been done to measure extent of brake pulling along with measurement of brake torque and speed etc.
2017-09-17
Technical Paper
2017-01-2513
Haocheng Li, Zhuoping Yu, Lu Xiong, Wei Han
With the development of electric vehicles, electronic hydraulic brake system becomes a hot spot of present research. In this paper,a new type of integrated electronic hydraulic brake(I-EHB) system is introduced, which is mainly composed of a motor, a worm gear, a worm, a gear, a rack etc. Motor and mechanical structure can cause friction, which leads the system to the creeping phenomenon and the dead zone. These phenomenon seriously affect the response speed and the hydraulic pressure control .In order to realize the accurate hydraulic pressure control of I-EHB system, a new friction compensation control method is proposed based on LuGre dynamic friction model. Because of the external interference or the abrasion of the system, the main parameters will change over time. So the adaptive control is of great importance. The theoretical design of adaptive control method is designed based on the feedback of the master cylinder pressure and the operating state of the system.
2017-09-17
Technical Paper
2017-01-2491
Baskar Anthonysamy, Arun Kumar Prasad, Babasaheb Shinde
Fierce competition in India’s automotive industry has led to constant production innovation among manufacturers. This has resulted in the reduction of the life cycle of the design philosophies and design tools. One of the performance factors that have continues to challenge automotive designer is to design and fine tune the braking performance with low cost and short life cycle. Improvement in braking performance and vehicle stability can be achieved through the use of braking systems whose brake force distribution is variable. Braking force distribution has an important and serious role in the vehicle stopping distance and stability. In this paper a new approach will be presented to achieve the braking force distribution strategy for articulated vehicles. For this purpose, the virtual optimization process has been implemented. This strategy, defined as an innovative braking force distribution strategy, is based on the wheel slips.
2017-09-17
Technical Paper
2017-01-2494
Severin Huemer-Kals, Manuel Pürscher, Peter Fischer
Complex Eigenvalue Analysis (CEA) is widely established as a mid- to high-frequency squeal simulation tool for automobile brake development. As low-frequency phenomena like creep groan or moan become increasingly important and appropriate time-domain methods are presently immature and expensive, some related questions arise: Is it reasonable to apply a CEA method for low-frequency brake vibrations? Which conditions in general have to be fulfilled to evaluate a disk brake system’s noise, vibration and harshness (NVH) behavior by the use of CEA simulation methods? Therefore, a breakdown of the mathematical CEA basis is performed and its linear, quasi-static approach is analyzed. The mode coupling type of instability, a common explanation model for squeal, is compared with the expected real world behavior of creep groan and moan phenomena.
2017-09-17
Technical Paper
2017-01-2493
Sivakumar Palanivelu, Jeevan Patil, Ajit Kumar Jindal
Brake system represents an important aspect of the vehicle dynamics apart from being an active safety system. The vehicle retardation and stopping distance completely depend upon the performance of brake system and the functionality of all components. However, the performance prediction of the entire system is a challenging task especially for a complex configuration such as multi-axial vehicle applications. Furthermore, due to its complexity most often the performance prediction by some methods is limited to static condition. Hence, it is very important to have equivalent mathematical models to predict all performance parameters for a given configuration in all different conditions. This paper presents the adopted system modelling approach to model all the elements of the pneumatic brake system such as dual brake valve, relay valve, quick release valve, front and rear brake actuators, foundation brake etc.
2017-09-17
Technical Paper
2017-01-2535
Yongbing Xu, Binyu Mei, Longjie Xiao, Wanyang XIA, Gangfeng Tan
The continuous braking of the brake drum will cause the brake thermal decay when the heavy truck is driving down the long slope in the mountain areas. This reduces the braking performance and the braking safety. The engine braking and the retarder braking both consume the kinetic energy of the truck and can assist the truck driving in the mountain areas. This research proposes a combined braking strategy of the heavy truck in the mountain areas based on the mountain GIS information and the former recorded information of the slope gradient. The accelerator pedal is released in the middle of the uphill to assist the engine braking and access the shift between the kinetic energy and the potential energy. Different braking methods are allocated properly according to the slope length and gradient in the downhill. The vehicle dynamic model is established to analyze the speed variation and the truck’s braking characteristics on the long slope.
2017-09-17
Technical Paper
2017-01-2533
Thomas J. Hall
As Pure Electric Vehicles have become a recent entrant to the higher end Passenger Vehicle Market, general interest in the overall technology has expanded beyond the environmental interest into the pure performance opportunities associated with electrically driven vehicles. Recently a new Racing Series has formed that is dedicated to Electric Vehicle Racing. Specifically the Formula-E® series has emerged as a venue for competition for Pure Electric open wheel race cars competing on Road Courses throughout the world. Success in the race series is influenced by the available energy that can be stored in the battery along with the applicable electrical efficiencies associated with the drive and control of the Propulsion Motors. The Race series also allows Regenerative Braking.
2017-09-17
Journal Article
2017-01-2532
David B. Antanaitis, Michael Shenberger, Max Votteler
The high performance brake systems of today are usually in a delicate balance - walking the fine line between being overpowered by some of the most potent powertrains, some of the grippiest tires, and some of the most demanding race tracks that the automotive world has ever seen - and saddling the vehicle with excess kilograms of unsprung mass with oversized brakes, forcing significant compromises in drivability with oversized tires and wheels. Brake system design for high performance vehicles has often relied on a very deep understanding of friction material performance (friction, wear, and compressibility) in race track conditions, with sufficient knowledge to enable this razor’s edge design.
2017-09-17
Technical Paper
2017-01-2508
Xianyao Ping, Shengguang Xiong, Gangfeng Tan, Jialiang Liu
Abstract Using friction brakes for long time can increase easily its temperature and lower vehicle brake performance in the downhill process. The drivers' hysteretic perception to future driving condition could mislead them to stop untimely the engine brake, and some other auxiliary braking devices are designed to increase the brake power for reduction of the friction brake torque. The decompression engine brake has complex structure and high cost, and the application of eddy current retarder or hydraulic retarder on the commercial vehicles is mainly limited to their cost and mass. In this paper, an innovative brake guidance system for commercial vehicles with coordinated friction brakes and engine brake is introduced to guide the drivers to minimize the use of the friction brakes on the downhill with consideration of future driving conditions, which is aimed at releasing the engine brake potential fully and controlling the friction brake temperature in safe range.
2017-09-17
Technical Paper
2017-01-2510
Shengguang Xiong, Gangfeng Tan, Bo Yang, Longjie Xiao, Yongbing Xu, Yishi Wang
Abstract Fluid auxiliary braking devices can provide braking torque through hydraulic damping, fluid auxiliary braking devices can also convert vehicular inertia energy into transmission fluid heat energy during the braking, which can effectively alleviate the work pressure of the main brake. Traditional hydraulic auxiliary braking devices use transmission fluids to transmit torque, however, there is a certain lag effect during the braking. The magnetorheological fluid (MR fluid) can also be used to transmit torque because it has the advantages of controlling braking torque linearly and responding fast to the magnetic field changed. The temperature of MR fluid will increase when the vehicle is engaged in continuous braking. MR fluid temperature changes will cause a bad influence on the efficiency stability of auxiliary braking.
2017-09-17
Technical Paper
2017-01-2515
Christian Riese, Armin Verhagen, Simon Schroeter, Frank Gauterin
Abstract The ongoing changes in the development of new power trains and the requirements due to driver assistance systems and autonomous driving could be the enabler for completely new brake system configurations. The shift in the brake load collective has to be included in the systems requirements for electric vehicles. Many alternative concepts for hydraulic brake systems, even for decentralized configurations, can be found in the literature. For a decentralized system with all state of the art safety functionalities included, four actuators are necessary. Therefore, the single brake module should be as cost-effective as possible. Previous papers introduced systems which are for example based on plunger-like concepts, which are very expensive and heavy due to the needed gearing and design. In this paper a comparison between a state of the art hydraulic brake system using an electromechanical brake booster, and a completely new decentralized hydraulic brake concept is presented.
Viewing 61 to 90 of 19997