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Viewing 1 to 30 of 649
2011-04-12
Technical Paper
2011-01-0170
Ashok D. Khondge, Sandeep Sovani, Gunjan Verma
Thorough design exploration is essential for improving vehicle performance in various aspects such as aerodynamic drag. Shape optimization algorithms in combination with computational tools such as Computational Fluid Dynamics (CFD) play an important role in design exploration. The present work describes a Free-Form Deformation (FFD) approach implemented within a general purpose CFD code for parameterization and modification of the aerodynamic shape of real-life vehicle models. Various vehicle shape parameters are constructed and utilized to change the shape of a vehicle using a mesh morphing technique based on the FFD algorithm. Based on input and output parameters, a design of experiments (DOE) matrix is created. CFD simulations are run and a response surface is constructed to study the sensitivity of the output parameter (aerodynamic drag) to variations in each input parameter.
2011-04-12
Technical Paper
2011-01-0169
Robert Louis Lietz
Recent advances in morphing, simulation, and optimization technologies have enabled analytically driven aerodynamic shape optimization to become a reality. This paper will discuss the integration of these technologies into a single process which enables the aerodynamicist to optimize vehicle shape as well as gain a much deeper understanding of the design space around a given exterior theme.
2011-04-12
Journal Article
2011-01-0151
Taeyoung Han, Chris Hill, Shailesh Jindal
Understanding the flow characteristics and, especially, how the aerodynamic forces are influenced by the changes in the vehicle body shape, are very important in order to improve vehicle aerodynamics. One specific goal of aerodynamic shape optimization is to predict the local shape sensitivities for aerodynamic forces. The availability of a reliable and efficient sensitivity analysis method will help to reduce the number of design iterations and the aerodynamic development costs. Among various shape optimization methods, the Adjoint Method has received much attention as an efficient sensitivity analysis method for aerodynamic shape optimization because it allows the computation of sensitivity information for a large number of shape parameters simultaneously.
2011-04-12
Journal Article
2011-01-0509
Megumu Oshima, Kanya Nara
This paper describes the development of a design method and process for quality variation control. Conventional approaches utilizing Taguchi method [6,7,8] can quantify the sensitivities of parts characteristics on a system characteristic from both viewpoints of nominal value and variation. But the interpretation of the sensitivities depends on engineers' judgments. At the new process, function deployment has been introduced as the tool for breaking down hierarchically vehicle performance to the level of parts characteristics. And the relation between vehicle performance and parts characteristics is formulated based on a physical model in order to interpret the sensitivities more technically. The methodology combining the formulated function deployment and Taguchi method is referred to as design response analysis and variation effect analysis. These approaches can facilitate the interpretation of the quantified sensitivities considering the mechanism.
2011-04-12
Technical Paper
2011-01-0510
Megumu Oshima, Kanya Nara, Tatsuhiko Yoshimura
We have constructed a design review system in which Full Process and Quick Design Review processes are selectively used according to the degree of newness in a design change. The Full Process Design Review is conducted for a review of system or part designs having a high level of newness and the tools and process used in this review were standardized. The Quick Design Review is newly developed design review process that could be conducted in a quicker and simpler manner for designs involving a medium level of newness in order to effectively prevent design-related problems. The Quick Design Review uses a changes list and Design Review Based on Failure Mode (DRBFM) [1] worksheets to focus on the changed points. This method enables the engineers involved to identify problems and to devise solutions efficiently and effectively through discussions.
2011-04-12
Technical Paper
2011-01-0594
Silviu Pala, Thomas Schnell, Nicole Lynn Becklinger, Carolina Giannotti, Bo Sun, Hiroaki Tanaka, Ifushi Shimonomoto
DENSO International America, Inc. and the University of Iowa-Operator Performance Laboratory (OPL) have developed a series of new Multi-Modal Interface for Drivers (MMID) in order to improve driver safety, comfort, convenience and connectivity. Three MMID concepts were developed: GUI 1, GUI 2 and GUI 1-HUD. All three of the MMIDs used a new Reconfigurable Haptic Joystick (RHJ) on the steering wheel and new concept HMI Dual Touch Function Switches (DTFS) device. The DTFS use capacitive and mechanic sensing located on the back of the steering wheel as input operation devices. Inputs from the new controls were combined with a large TFT LCD display in the instrument cluster, a Head Up Display (HUD) and Sound as output devices. The new MMID system was installed in a Lexus LS-430. The climate control panel and radio panels of the LS-430 were used as a baseline condition to which the new designs were compared.
2013-04-08
Technical Paper
2013-01-1233
Sreegururaj Jayachander
The current trend of going “green” in emerging automotive markets is, by the conversion of internal combustion engine based vehicle platforms into electrified vehicle platforms. While this method of electrification reduces the product development life cycle drastically due to the availability of a readymade platform, there are certain areas that are always overlooked. While focus is given on obvious and necessary elements like power train & battery packaging, weight reduction, high voltage safety, thermal management etc., electro-magnetic compatibility is neglected in the conversion process. This paper shall describe, in detail and in particular, the effect of electrical transients created by legacy elements, already existing in the baseline platform. This is an outcome of electro-magnetic compatibility challenges faced during the conversion of an internal combustion engine powered vehicle into an electric vehicle.
2013-10-07
Technical Paper
2013-36-0353
Luciano Magno Frágola Barbosa, José Eduardo Mautone de Barros
The aim of this work is to present the preliminary configuration design studies for an unmanned, lightweight (less than 15 kg), supersonic research aircraft. The studies comprise the aircraft typical mission, the aerodynamic and structural arrangement, preliminary performance, as well as mass distribution. The aircraft, an Unmanned Air Vehicle, or “UAV”, is named as Pohox (“arrow” in Maxakali indian language). It is intended to be the flying test bed for a multicycle engine capable to provide thrust in subsonic, transonic and supersonic regimes. In order to provide validation of the analysis tools, flight performance characteristics of a known, high speed aircraft - North American X-15 - have been also evaluated and compared with the available flight test data. The present analysis is an important step towards the aircraft detailed definition. And the features associated with the configuration obtained are good indications of the technical feasibility of this supersonic UAV.
2013-10-07
Technical Paper
2013-36-0541
Eloy Martins de Oliveira Junior, Marcelo Lopes de Oliveira e Souza
Current systems such as satellites, aircrafts, automobiles, turbines, power controls and traffic controls are becoming increasingly complex and/or highly integrated as prescribed by the SAE-ARP-4754a Standard. Such systems operate in a real time distributed environment which frequently requires a common knowledge of time among different devices, levels and granularities. So, temporal correctness is mostly needed, besides logical correctness. It can be achieved by hardware clocks and devices, software clocks and algorithms, or both, to avoid or tolerate, within appropriate margins, the time faults or failures that may occur in aerospace and automotive systems. This paper presents an overview of clock synchronization algorithms and their uses in aerospace and automotive systems. It is based on a review of the literature, discussion and comparison of some clock synchronization algorithms with different policies.
2011-04-12
Journal Article
2011-01-1080
Vijitashwa Pandey, Efstratios Nikolaidis, Zissimos Mourelatos
Multi-attribute decision making and multi-objective optimization complement each other. Often, while making design decisions involving multiple attributes, a Pareto front is generated using a multi-objective optimizer. The end user then chooses the optimal design from the Pareto front based on his/her preferences. This seemingly simple methodology requires sufficient modification if uncertainty is present. We explore two kinds of uncertainties in this paper: uncertainty in the decision variables which we call inherent design problem (IDP) uncertainty and that in knowledge of the preferences of the decision maker which we refer to as preference assessment (PA) uncertainty. From a purely utility theory perspective a rational decision maker maximizes his or her expected multi attribute utility.
1999-10-19
Technical Paper
1999-01-5629
Martin Kraus, Rudolf Heinzinger, Hans-Christoph Oelker
Integration of ground-based testing into the airborne testing process is presented in terms of an advanced test and analysis concept. Based on the discussion, that running a simulator is less expensive than performing a test flight, means of combining both methodologies are being presented and discussed. The idea is to perform selected tests on ground-based facilities under test flight conditions. This is called Virtual Flight Testing. For explanation of this idea an example is given and a representative result is presented. Another main pillar of this advanced test and analysis concept is on-line analysis. A recent tool for this purpose is on-line simulation, which is introduced with a brief overview together with an illustrative example. The paper gives an introduction into DASA’s efforts to increase efficiency of the testing process. The main goal is an early feedback of test information into the design process in order to improve this process.
1999-10-19
Technical Paper
1999-01-5631
Michelle R. Kirby, Dimitri N. Mavris
An evolved version of the Technology Identification, Evaluation, and Selection (TIES) method is presented that provides techniques for quantifying technological uncertainty associated with immature technologies. Uncertainty in this context implies forecasting. Forecasting the impact of immature technologies on a system is needed to provide increased knowledge to a decision-maker in the conceptual and preliminary phases of aircraft design. The increased knowledge allows for proper allocation of company resources and program management. The TIES method addresses the milestones encountered during a technology development program, the sources of uncertainty during that development, a potential method for bounding and forecasting the uncertainty, and a means to quantify the impact of any emerging technology. A proof of concept application was performed on a High Speed Civil Transport concept due to its technically challenging customer requirements.
1999-10-19
Technical Paper
1999-01-5639
Mark A. Hale, Dimitri N. Mavris, Dennis L. Carter
The Conceptual Aerospace Systems Design and Analysis Toolkit (CASDAT) provides a baseline assessment capability for the Air Force Research Laboratory. The historical development of CASDAT is of benefit to the design research community because considerable effort was expended in the classification of the analysis tools. Its implementation proves to also be of importance because of the definition of assessment use cases. As a result, CASDAT is compatible with accepted analysis tools and can be used with state-of-the-art assessment methods, including technology forecasting and probabilistic design.
1999-10-19
Technical Paper
1999-01-5546
Archie E. Dillard
The rapid implementation of multifunction display (MFD) designs in new aircraft has increased the need for aerospace recommended practices (ARP) for use by manufacturers and users. The large amount of information available for display creates a number of human factors problems that must be addressed in the design phase in order to produce a safe and usable display system. Color, clutter, prioritization, switching, symbology, and compatibility are only a few of the areas that require guidance. This presentation will review the work to date by the SAE G-10 Multifunction Display Subcommittee on an ARP that will address these issues and others.
1999-10-19
Technical Paper
1999-01-5520
Mark S. Grahne, David P. Cadogan
The planned increase in satellite launches over the next decade will emphasize reduction of space hardware mass and launch costs. Inflatable structures present many benefits over current state-of-the-art +mechanical technologies and are principally attractive because they can be packaged into small volumes, thereby reducing program costs. Reduced costs are realized in development and production as well as in enabling smaller launch vehicle size. Inflatable structures will reduce total system mass and complexity, thereby increasing system reliability. This paper describes several types of inflatable structures and applications being developed for space flight. Rigidization methods and results from preflight test programs are also presented to support the viability of the technology.
1999-10-19
Technical Paper
1999-01-5515
James L. Hunt, Robert J. Pegg, Dennis H. Petley
This paper presents the status of the airbreathing hypersonic airplane and space-access vision-operational-vehicle design matrix, with emphasis on horizontal takeoff and landing systems being studied at Langley; it reflects the synergies and issues, and indicates the thrust of the effort to resolve the design matrix including Mach 5 to 10 airplanes with global-reach potential, pop-up and dual-role transatmospheric vehicles and airbreathing launch systems. The convergence of several critical systems/technologies across the vehicle matrix is indicated. This is particularly true for the low speed propulsion system for large unassisted horizontal takeoff vehicles which favor turbines and/or perhaps pulse detonation engines that do not require LOX which imposes loading concerns and mission flexibility restraints.
1999-10-19
Technical Paper
1999-01-5530
Ray Whitford
Different feasibility studies have been carried out over several years at the Royal Military College of Science (RMCS) into medium military airlifters aimed, in essence at replacing the C-130. The studies, each occupying a nominal 1,500 manhours (but probably 50% more) formed part of the final year of the AeroMechanical B.Eng degree at RMCS. The intention of this paper is to draw together their major findings and deals predominantly with the topics of: cargo hold sizing and body aerodynamics, powerplant selection, weight and performance.
2011-06-13
Technical Paper
2011-38-0055
Richard Moser, Roger Gent
The European Union (EU) ‘Clean Sky’ [1] Joint Technology Initiative (JTI) is a research programme aimed at developing breakthrough technologies which will minimise the impact of aviation on the environment. Within this, the System for Green Operations (SGO) Integrated Technology Demonstrator (ITD) looks to improve aircraft operation through management of energy and mission trajectory. As part of the SGO ITD, a series of environmental icing tests have been conducted on an ice protected, acoustically protected, electrically powered, scoop intake and channel. The range of conditions tested included in-flight icing (CS-25 Appendix C, same as 14 CFR 25), super-cooled large droplets (proposed 14 CFR 25 Appendix O, [2]), snow and ice crystal conditions as well as ground icing in freezing fog conditions.
2011-10-18
Technical Paper
2011-01-2713
Felix Jakob, Silvia Mazzini, Andreas Jung
This paper describes an approach for a SysML-based methodology, recently defined and applied at the European Space Agency (ESA). In 2009 a SysML-based methodology based on the European Cooperation for Space Standardization (ECSS) and International Organization for Standardization (ISO) standards was developed in the frame of the European Space Agency (ESA)/European Space Research and Technology Centre (ESTEC) study “System and Software Functional Requirements Techniques” (SSFRT).The SSFRT study investigated the feasibility of the application of model-based system engineering in spacecraft design to support the space system and software development processes, from mission level requirements to software implementation. The use of models to support the system requirements engineering process was aimed at improving the system requirements allocation process toward the software requirements engineering process.
2012-10-22
Technical Paper
2012-01-2137
Luc Marcil
This white paper explains the benefits of the Model-Based Design (MBD) approach and Object-Oriented Technology (OOT) that DO-178C provides. It also specifically focuses on the usage of Models and COTS Qualifiable tools that automate or facilitate the verification and validation of avionics applications constructed from Models in order to ensure that there is no unintended function. Software running in Aircraft cockpits has dramatically increased in complexity since DO-178B's revision in 1992. Furthermore, over the past 20 years, software development methods have made significant leaps forward and DO-178B has begun to show its age with respect to the new technology introduced to facilitate software development. This year the newly revamped DO-178C standard sets the certification process record straight by embracing modern technology.
2012-10-22
Technical Paper
2012-01-2132
Devesh Bhatt, Gabor Madl, David Oglesby
An approach is described for the static analysis of component models in an integrated context driven by system and software architecture configuration. This satisfies an important verification objective for the certification of avionics systems and can significantly reduce certification costs by identifying design problems early in the development cycle. The methodology is implemented in a toolset that performs the model-based integrated analysis of computing signal range, error bounds, and identifying design defects. Classes of design defects are described that are detected using this toolset and usage examples are presented.
2012-10-22
Technical Paper
2012-01-2133
Laurent Moss, Hubert Guerard, Gary Dare, Guy Bois
This paper presents an Electronic System-Level (ESL) methodology and framework for the system specification, design space exploration, performance analysis, and hardware/software implementation of aerospace electronic systems subject to Quality of Results (QoR) constraints such as execution time, communication rate, technology, as well as Size, Weight and Power (SWaP). In particular, we show how SWaP constraints could be converted into bounds on the target hardware platform, how several potential architectures could be devised for the system, how each potential architecture and mapping could be evaluated for performance, hardware resource usage and power taking into account the impact of Triple Modular Redundancy (TMR), and how a selected architecture could be exported as a hardware/software Register-Transfer Level (RTL) implementation.
2011-09-11
Technical Paper
2011-24-0163
V. K. Krastev, G. Bella
Computational Fluid Dynamics is nowadays largely employed as an effective optimization tool in the automotive industry, especially for what concerns aerodynamic design driven by critical factors such as the engine cooling system optimization and the reduction of drag forces, both limited by continuously changing stylistic constraints. The Ahmed reference model is a generic car-type bluff body with a slant back, which is frequently used as a benchmark test case by industrial as well as academic researchers, in order to investigate the performances of different turbulence modeling approaches. In spite of its relatively simple geometry, the Ahmed model possesses many of the typical aerodynamic features of a modern passenger car - a bluff body with separated boundary layers, recirculating flows and complex three-dimensional wake structures.
2015-09-22
Technical Paper
2015-36-0364
Everton Spuldaro, Justin Donoghue, Jacob Hough, Bruno Rocha
Abstract A long endurance high efficiency Unmanned Aerial Vehicle (UAV) is being developed by a group of researchers and students in the Mechanical Engineering Technology program at Algonquin College, Ottawa, ON, Canada. The design is based on a tailless, staggered tandem wing configuration, with a carbon fiber frame and electric propulsion. The developed aircraft has a maximum weight of 12.5 kg, well within the 25 kg limit outlined by Transport Canada for permission-free operation. The UAV was designed to fly missions exceeding 24 hours, performing surveillance and oil pipeline monitoring and inspection, either autonomously or under radio control from a ground station, with medium to high payload capacity. This paper describes the process of designing, manufacturing and testing the developed configuration. The operational requirements are delineated as conceptualized by the development team.
2015-09-22
Technical Paper
2015-36-0445
Jairo Cavalcanti Amaral, Marcelo Lopes de Oliveira e Souza
Abstract Control systems that can switch between control or plant modes have the advantage of being simpler to design than an equivalent system with a single mode. However, the transition between these modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the system. This is can be of extreme importance in fields such as aerospace and automobilistic, as the switching between manual and autopilot modes or the switching of gears In this work, we will use integral criteria in original ways, to determine a coefficient on the system which should optimize the trajectory of the control signal, during the switching between two modes. Effectively, each transition will be done by a subsystem specific for it, according to the selected criterion. The simulations will be made in MATRIXx, MatLab or both, using models chosen from aerospace or automobilistic fields.
2007-09-17
Technical Paper
2007-01-3929
Ilhan Tuzcu
This paper concerns with control of Unmanned Aerial Vehicles (UAVs), which are expected to carry out very critical maneuvers, well in excess of what pilots are able to tolerate. Safety factors for these aircraft are not as high as those for manned aircraft and they are lighter than the manned aircraft. These imply that UAVs are considerably more flexible than the manned aircraft. A newly developed theory for the dynamics and control of maneuvering flexible aircraft is ideally suited for the analysis and design of such aircraft. The control input can be conceived as having two parts, one part designed to steer the aircraft to permit the realization of a desired flight trajectory and another part designed to reduce any deviations from the desired trajectory. Control design for steering the aircraft can be achieved by using the inverse dynamics of quasi-rigid aircraft (aircraft treated as rigid). On the other hand, control design for the deviations requires output feedback control.
2009-10-06
Technical Paper
2009-36-0160
Humberto Manelli Neto, Gustavo Bernardes Sousa, Marcelo Lopes de Oliveira e Souza
This paper aims at discussing the use of dissimilar hardware architecture to mitigate DESIGN ERRORS in a flight control system application, as one of the possible design techniques that, combined with the usage of development processes, will satisfy the safety objectives for airborne systems. To accomplish its purpose, the paper starts by understanding the origins of DESIGN ERRORS in micro-coded devices and the concerns of airworthiness certification authorities (or simply certification authorities from now on). After that, an overview of the aeronautical industry efforts in terms of development processes and certification requirements to mitigate DESIGN ERRORS will be presented. At this point, the dissimilar architecture is proposed as an effective mean to mitigate the problem of DESIGN ERRORS. Finally, a Flight Control System application using dissimilar architecture is proposed as a case study.
2009-07-12
Technical Paper
2009-01-2386
Robert Sompayrac, Bruce Conger, Mateo Chamberlain, Heather L. Paul
As development of the Constellation spacesuit element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges that are associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control; to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream; and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study, and also describes the conceptual designs that NASA developed to address these issues.
2009-07-12
Technical Paper
2009-01-2586
James Chartres, Brian Koss, Chad Brivkalns, Bruce Webbon, Barbara Romig, Charles Allton
This paper present a summary of the design studies for the suit port proof of concept. The Suit Port reduces the need for airlocks by docking the suits directly to a rover or habitat bulkhead. The benefits include reductions in cycle time and consumables traditionally used when transferring from a pressurized compartment to EVA and mitigation of planetary surface dust from entering into the cabin. The design focused on the development of an operational proof of concept evaluated against technical feasibility, level of confidence in design, robustness to environment and failure, and the manufacturability. A future paper will discuss the overall proof of concept and provide results from evaluation testing including gas leakage rates upon completion of the testing program.
2009-07-12
Technical Paper
2009-01-2457
John F. Lewis, Richard A. Barido, Robyn Carrasquillo, Cynthia D. Cross, Ed Rains, George C. Tuan
The Crew Exploration Vehicle (CEV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. The CEV is being developed to transport the crew safely from the Earth to the International Space Station and then later, from the Earth to the Moon . This year, the vehicle continued to go through design refinements to reduce weight, meet requirements, and operate reliably while preparing for Preliminary Design Review in the summer of 2009. The design of the Orion Environmental Control and Life Support (ECLS) system, which includes the life support and active thermal control systems, is progressing through the design stage. This paper covers the Orion ECLS development from April 2008 to April 2009.
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