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2017-08-29
Journal Article
2017-01-9000
Teresa Donateo, Antonio Ficarella
Abstract The design of a hybrid electric powertrain requires a complex optimization procedure because its performance will strongly depend on both the size of the components and the energy management strategy. The problem is particular critical in the aircraft field because of the strong constraints to be fulfilled (in particular in terms of weight and volume). The problem was addressed in the present investigation by linking an in-house simulation code for hybrid electric aircraft with a commercial many-objective optimization software. The design variables include the size of engine and electric motor, the specification of the battery (typology, nominal capacity, bus voltage), the cooling method of the motor and the battery management strategy. Several key performance indexes were suggested by the industrial partner. The four most important indexes were used as fitness functions: electric endurance, fuel consumption, take-off distance and powertrain volume.
2017-07-10
Technical Paper
2017-28-1949
Johnson Jose, Ramesh M, G Venkatesan, M Khader Basha
Abstract Unmanned Aerial Vehicles (UAV) are being deployed in military, law enforcement, search & rescue, scientific research, environmental & climate studies, reconnaissance and other commercial and non-commercial applications on a large scale. A design and development of landing gear system has been taken up for a UAV. This paper presents the design optimization of structural components of Wheel-Brake & Fork assembly pertaining to the Main Landing Gear (MLG) for a UAV. The wheel, fork, axle and brake unit constitute the wheel assembly. The wheel-brake assembly is assembled with the strut assembly and forms the Landing gear system. The Fork is the connecting member between the shock strut and the axle containing the wheel-brake assembly. As the fork and axle are subjected to shock loads while landing, the strength of these components are very much essential to withstand the dynamic loads.
2017-06-05
Technical Paper
2017-01-1764
Himanshu Amol Dande, Tongan Wang, John Maxon, Joffrey Bouriez
Abstract The demand for quieter interior cabin spaces among business jet customers has created an increased need for more accurate prediction tools. In this paper, the authors will discuss a collaborative effort between Jet Aviation and Gulfstream Aerospace Corporation to develop a Statistical Energy Analysis (SEA) model of a large commercial business jet. To have an accurate prediction, it is critical to accurately model the structural and acoustic subsystems, critical noise transmission paths, and dominant noise sources for the aircraft. The geometry in the SEA model was developed using 3D CAD models of major airframe and interior cabin components. The noise transmission path was characterized through extensive testing of various aircraft components in the Gulfstream Acoustic Test Facility. Material definitions developed from these tests became input parameters in the SEA model.
2017-03-28
Journal Article
2017-01-1528
Levon Larson, Ronald Gin, Robert Lietz
Abstract Cooling drag is a metric that measures the influence of air flow travelling through the open grille of a ground vehicle on overall vehicle drag, both internally (engine air flow) and externally (interference air flow). With the interference effects considered, a vehicles cooling drag can be influenced by various air flow fields around the vehicle, not just the air flow directly entering or leaving the engine bay. For this reason, computational fluid dynamics (CFD) simulations are particularly difficult. With insights gained from a previously conducted set of experimental studies, a CFD validation effort was undergone to understand which air flow field characteristics contribute to CFD/test discrepancies. A Lattice-Boltzmann Large Eddy Simulation (LES) method was used to validate several test points. Comparison using integral force values, surface pressures, and cooling pack air mass flows was presented.
2017-03-28
Journal Article
2017-01-1525
Kosuke Nakasato, Makoto Tsubokura, Jun Ikeda, Keiji Onishi, Shoya Ota, Hiroki Takase, Kei Akasaka, Hisashi Ihara, Munehiko Oshima, Toshihiro Araki
Abstract Because of rising demands to improve aerodynamic performance owing to its impact on vehicle dynamics, efforts were previously made to reduce aerodynamic lift and yawing moment based on steady-state measurements of aerodynamic forces. In recent years, increased research on dynamic aerodynamics has partially explained the impact of aerodynamic forces on vehicle dynamics. However, it is difficult to measure aerodynamic forces while a vehicle is in motion, and also analyzing the effect on vehicle dynamics requires measurement of vehicle behavior, amount of steering and other quantities noiselessly, as well as an explanation of the mutual influence with aerodynamic forces. Consequently, the related phenomena occurring in the real world are still not fully understood.
2017-03-28
Journal Article
2017-01-1512
Fuliang Wang, Zhangshun Yin, Shi Yan, Jia Zhan, Heinz Friz, Bo Li, Weiliang Xie
Abstract The validation of vehicle aerodynamic simulation results to wind tunnel test results and simulation accuracy improvement attract considerable attention of many automotive manufacturers. In order to improve the simulation accuracy, a simulation model of the ground effects simulation system of the aerodynamic wind tunnel of the Shanghai Automotive Wind Tunnel Center was built. The model includes the scoop, the distributed suction, the tangential blowing, the moving belt and the wheel belts. The simulated boundary layer profile and the pressure distribution agree well with test results. The baseline model and multiple design changes of the new Buick Excelle GT are simulated. The simulation results agree very well with test results.
2017-03-28
Journal Article
2017-01-1521
Levon Larson, Sudesh Woodiga, Ronald Gin, Robert Lietz
Abstract The airflow that enters the front grille of a ground vehicle for the purpose of component cooling has a significant effect on aerodynamic drag (engine airflow drag). Furthermore, engine airflow is known to be capable of influencing upstream external airflow (interference drag). The combined effect of these phenomena is commonly referred to as cooling drag, which generally contributes up to 10% of total vehicle drag. Due to this coupled nature, cooling drag is difficult to understand as it contains influences from multiple locations around the vehicle. A good understanding of the sources of cooling drag is paramount to drive vehicle design to a low cooling drag configuration. In this work, a production level Lincoln MKZ was modified so that a number of variables could be tested in both static ground and moving ground wind tunnel conditions. All tests were conducted at 80 MPH.
2017-03-28
Journal Article
2017-01-1546
Joshua Newbon, David Sims-Williams, Robert Dominy
Abstract The effect of the upstream wake of a Formula 1 car on a following vehicle has been investigated using experimental and computational methods. Multiple vehicle studies in conventional length wind tunnels pose challenges in achieving a realistic vehicle separation and the use of a short axial length wake generator provides an advantage here. Aerodynamic downforce and drag were seen to reduce, with greater force reductions experienced at shorter axial spacings. With lateral offsets, downforce recovers at a greater rate than drag, returning to the level for a vehicle in isolation for offsets greater than half a car width. The effect of the wake was investigated in CFD using multiple vehicle simulations and non-uniform inlet boundary conditions to recreate the wake. Results closely matched those for a full two-vehicle simulation provided the inlet condition included unsteady components of the onset wake.
2017-03-28
Journal Article
2017-01-1549
Taro Yamashita, Takafumi Makihara, Kazuhiro Maeda, Kenji Tadakuma
Abstract In recent years, the automotive manufacturers have been working to reduce fuel consumption in order to cut down on CO2 emissions, promoting weight reduction as one of the fuel saving countermeasures. On the other hand, this trend of weight reduction is well known to reduce vehicle stability in response to disturbances. Thus, automotive aerodynamic development is required not only to reduce aerodynamic drag, which contributes directly to lower fuel consumption, but also to develop technology for controlling unstable vehicle behavior caused by natural wind. In order to control the unstable vehicle motion changed by external contour modification, it is necessary to understand unsteady aerodynamic forces that fluctuating natural wind in real-world environments exerts on vehicles. In the past, some studies have reported the characteristics of unsteady aerodynamic forces induced by natural winds, comparing to steady aerodynamic forces obtained from conventional wind tunnel tests.
2017-03-28
Technical Paper
2017-01-1592
Jingdong Cai, Saurabh Kapoor, Tushita Sikder, Yuping He
Abstract In this research, active aerodynamic wings are investigated using numerical simulation in order to improve vehicle handling performance under emergency scenarios, such as tight cornering maneuvers at high speeds. Air foils are selected and analyzed to determine the basic geometric features of aerodynamic wings. Built upon the airfoil analysis, the 3-D aerodynamic wing model is developed. Then, the virtual aerodynamic wings are assembled with the 3-D vehicle model. The resulting 3-D geometry model is used for aerodynamic analysis based on numerical simulation using a computational fluid dynamics (CFD) software package. The CFD-based simulation data and the vehicle dynamic model generated are combined to study the effects of active aerodynamic wings on handling performance of high-speed vehicles. The systematic numerical simulation method and achieved results may provide design guidance for the development of active aerodynamic wings for high-speed road vehicles.
2017-03-28
Journal Article
2017-01-1352
David Gardiner
Abstract This paper presents an experimental study of the vapour space flammability of Fuel Ethanol (a high-ethanol fuel for Flexible Fuel Vehicles, commonly known as “E85”) and gasoline containing up to 10% ethanol (commonly known as “E10”). The seasonal minimum vapour pressure limits in specifications for automotive spark ignition fuels are intended, in part, to minimize the formation of flammable mixtures in the headspace of vehicle fuel tanks. This is particularly important at subzero temperatures, where the headspace mixture may not be rich enough to prevent combustion in the presence of an ignition source such as a faulty electrical fuel pump. In the current study, the upper temperature limits of flammability were measured for field samples of “E85” and “E10”, and a series of laboratory-prepared blends of denatured ethanol, Before Oxygenate Blending (BOB) gasoline, and n-butane.
2017-03-28
Technical Paper
2017-01-1304
Alejandro Rosas Vazquez, Fernando Paisano, Diego Santillan Gutierrez
Abstract For many years, the use of in-mold fasteners has been avoided for various reasons including: not fully understanding the load cases in the part, the fear of quality issues occurring, the need for servicing, or the lack of understanding the complexity of all failure modes. The most common solution has been the use of secondary operations to provide attachments, such as, screws, metal clips, heat staking, sonic welding or other methods which are ultimately a waste in the process and an increase in manufacturing costs. The purpose of this paper is to take the reader through the design process followed to design an in-molded attachment clip on plastic parts. The paper explores the design process for in-molded attachment clips beginning with a design concept idea, followed by basic concept testing using a desktop 3D printer, optimizing the design with physical tests and CAE analysis, and finally producing high resolution 3D prototypes for validation and tuning.
2017-03-14
Journal Article
2017-01-9276
Joseph K. Ausserer, Marc D. Polanka, Jacob A. Baranski, Keith D. Grinstead, Paul J. Litke
Abstract The rapid expansion of the market for remotely piloted aircraft (RPA) includes a particular interest in 10-25 kg vehicles for monitoring, surveillance, and reconnaissance. Power-plant options for these aircraft are often 10-100 cm3 internal combustion engines. Both power and fuel conversion efficiency decrease with increasing rapidity in the aforementioned size range. Fuel conversion efficiency decreases from ∼30% for conventional-scale engines (>100 cm3 displacement) to <5% for micro glow-fuel engines (<10 cm3 displacement), while brake mean effective pressure decreases from >10 bar (>100 cm3) to <4 bar (<10 cm3). Based on research documented in the literature, the losses responsible for the increase in the rate of decreasing performance cannot be clearly defined.
2017-01-10
Technical Paper
2017-26-0336
Ganesh Liladhar Yewale, Abhishek Tapkire, D Radhakrishna, Popat Shejwal, Kaushal Singh, Gaurav Panchal
Abstract VRDE has developed Wankel type rotary engine to achieve high power output & fuel efficiency for indigenization programme of UAVs. This engine is meeting all performance parameters needed for intended aerial vehicle. This paper describes the testing methodology followed by development engineers to prove the endurance and reliability of UAV engine for airworthiness certification. This paper gives the brief about testing carried out on the Wankel engine, failures faced during endurance testing and their rectification to enhance the life of the engine to achieve hundred test cycle mark. This paper also briefs about the test set up, endurance test cycles simulating the practical operating conditions.
2016-11-08
Technical Paper
2016-32-0045
Joseph K. Ausserer, Marc D. Polanka, Jacob Baranski, Paul Litke
Abstract Small remotely piloted aircraft (10-25 kg) powered by internal combustion engines typically operate on motor gasoline, which has an anti-knock index (AKI) of >80. To comply with the single-battlefield-fuel initiative in DoD Directive 4140.25, interest has been increasing in converting the 1-10 kW power plants in the aforementioned size class to run on lower AKI fuels such as diesel and JP-8, which have AKIs of ∼20. It has been speculated that the higher losses (short circuiting, incomplete combustion, heat transfer) that cause these engines to have lower efficiencies than their conventional-scale counterparts may also relax the fuel-AKI requirements of the engines. To investigate that idea, the fuel-AKI requirement of a 3W-55i engine was mapped and compared to that of the engine on the manufacturer-recommended 98 (octane number) ON fuel.
2016-11-08
Technical Paper
2016-32-0078
Mark R. Mataczynski, Paul Litke, Benjamin Naguy, Jacob Baranski
Abstract Aircraft engine power is degraded with increasing altitude according to the resultant reduction in air pressure, temperature, and density. One way to mitigate this problem is through turbo-normalization of the air being supplied to the engine. Supercharger and turbocharger components suffer from a well-recognized loss in efficiency as they are scaled down in order to match the reduced mass flow demands of small-scale Internal Combustion Engines. This is due in large part to problems related to machining tolerance limitations, such as the increase in relative operating clearances, and increased blade thickness relative to the flow area. As Internal Combustion Engines decrease in size, they also suffer from efficiency losses owing primarily to thermal loss. This amplifies the importance of maximizing the efficiency of all sub-systems in order to minimize specific fuel consumption and enhance overall aircraft performance.
2016-11-07
Technical Paper
2016-22-0006
John R. Humm, Narayan Yoganandan, Frank A. Pintar, Richard L. DeWeese, David M. Moorcroft, Amanda M. Taylor, Brian Peterson
The objective of the present exploratory study is to understand occupant responses in oblique and side-facing seats in the aviation environment, which are increasingly installed in modern aircrafts. Sled tests were conducted using intact Post Mortem Human Surrogates (PMHS) seated in custom seats approximating standard aircraft geometry. End conditions were selected to represent candidate aviation seat and restraint configurations. Three-dimensional head center-of-gravity linear accelerations, head angular velocities, and linear accelerations of the T1, T6, and T12 spinous processes, and sacrum were obtained. Three-dimensional kinematics relative to the seat were obtained from retroreflective targets attached to the head, T1, T6, T12, and sacrum. All specimens sustained spinal injuries, although variations existed by vertebral level.
2016-10-25
Technical Paper
2016-36-0377
Alain Giacobini Souza, Luiz Carlos Gadelha Souza
Abstract In designing of the Attitude Control System (ACS) is important take into account the influence of the structure’s flexibility, since they can interact with the satellite rigid motion, mainly, during translational and/or rotational maneuver, damaging the ACS pointing accuracy. In the linearization and reduction of the rigid-flexible satellite mathematic model, usually one loses some important information associated with the satellite true dynamical behavior. One way to recovery this information is include to the ACS design parametric and not parametric uncertainties of the system. The H infinity control method is able to take into account the parametric uncertainty in the control law design, so the controller becomes more robust. This paper presents the design of a robust controller using the H infinity control technique to control the attitude of a rigid-flexible satellite.
2016-10-25
Technical Paper
2016-36-0437
Gustavo de Carvalho Bertoli, Geraldo José Adabo, Gefeson Mendes Pacheco
Abstract A method for conceptual design of Solar Powered Unmanned Aircraft System (UAS) is presented. This method is based on traditional design methodology - wing loading estimation for preliminary sizing - modified for Solar Powered UAS case. Based on past works on Solar Powered UAS design, proposes a method that considers payload power consumption and therefore its impact on battery sizing. This battery sizing composes vehicle conceptual sizing equation. This method is useful for an assessment of Solar Powered UAS use in specific missions and serving as a start point for a more detailed design. A user interface was developed to automate the design process based on this method proposed.
2016-09-27
Technical Paper
2016-01-2109
Michael Morgan, Caroline McClory, Colm Higgins, Yan Jin, Adrian Murphy
Aerospace structures are typically joined to form larger assemblies using screw lock or swage lock fasteners or rivets. Countersunk fasteners are used widely in the aerospace industry on flying surfaces to reduce excrescence drag and increase aircraft performance. These fasteners are typically installed to a nominal countersink value which leaves them flush to the surface before being locked into position. The Northern Ireland Technology Centre (NITC) at Queen’s University Belfast has developed and demonstrated two processes which enable high tolerance flush fastening of countersunk fasteners: The ‘Flush Install’ process produces countersunk holes based on the specific geometry of each individual fastener; The ‘Fettle Flush’ process accurately machines fasteners to match the surrounding surface. Flushness values well within the allowable tolerances have been demonstrated for both Flush Install and Fettle Flush processes.
2016-09-27
Technical Paper
2016-01-2098
Christophe Vandaele, Didier Friot, Simon Marry, Etienne Gueydon
Abstract With more than 10 000 aircrafts in their order backlog Aircraft manufacturers focus on automated assembly is of critical importance for the future of efficient production assembly. Moreover to obtain maximum benefit from automation, it is necessary to achieve not only an automated assembly cell, but also a real breakthrough in fastener technology. The optimum solution, known as “One Side Assembly”, performs the whole assembly sequence from one side of the structure using an accurate robot arm equipped with a multifunction end effector and high performance fasteners. This configuration provides an efficient and flexible automated installation process, superior to current solutions which are typically, large scale, capital intensive systems, which still require operators to complete or control the fastener installation. The search for a technological breakthrough in this domain has been targeted for more than 15 years by many aircraft manufacturers.
2016-09-27
Technical Paper
2016-01-2095
Agata Suwala, Lucy Agyepong, Andrew Silcox
Abstract Reduction of overall drag to improve aircraft performance has always been one of the goals for aircraft manufacturers. One of the key contributors to decreasing drag is achieving laminar flow on a large proportion of the wing. Laminar flow requires parts to be manufactured and assembled within tighter tolerance bands than current build processes. Drilling of aircraft wings to the tolerances demanded by laminar flow requires machines with the stiffness and accuracy of a CNC machine while having the flexibility and envelope of an articulated arm. This paper describes the development and evaluation of high accuracy automated processes to enable the assembly of a one-off innovative laminar flow wing concept. This project is a continuation of a previously published SAE paper related to the development of advanced thermally stable and lightweight assembly fixture required to maintain laminar flow tolerances.
2016-09-27
Journal Article
2016-01-2112
Hilmar Apmann
Abstract As a new material FML, made by aluminum foils and Glasfiber-Prepreg, is a real alternative to common materials for fuselages of aircrafts like monolithic aluminum or CFRP. Since experiences within A380 this material has some really good advantages and develops to the status as alternative to aluminum and composite structures. To become FML as a real alternative to aluminum and carbon structures there are many things to improve: design, material, costs and process chain. So following one of the main goals for an industrial application for high production rates of aircrafts is the automation of production processes inside the process chain for FML-parts like skins and panels for fuselages. To reach this goal for high production rates first steps of automation inside this new process chain have been developed in the last two years. Main steps is the automated lay-up of metallic foils and Glasfiber-Prepreg.
2016-09-27
Journal Article
2016-01-2119
Gergis W. William, Samir N. Shoukry, Jacky C. Prucz, Mariana M. William
Abstract Air cargo containers are used to load freight on various types of aircrafts to expedite their handling. Fuel cost is the largest contributor to the total cost of ownership of an air cargo container. Therefore, a better fuel economy could be achieved by reducing the weight of such containers. This paper aims at developing innovative, lightweight design concepts for air cargo containers that would allow for weight reduction in the air cargo transportation industry. For this purpose, innovative design and assembly concepts of lightweight design configurations of air cargo containers have been developed through the applications of lightweight composites. A scaled model prototype of a typical air cargo container was built to assess the technical feasibility and economic viability of creating such a container from fiber-reinforced polymer (FRP) composite materials. The paper is the authoritative source for the abstract.
2016-09-27
Technical Paper
2016-01-2130
Enkhsaikhan Boldsaikhan, Shintaro fukada, Mitsuo Fujimoto, Kenichi Kamimuki, Hideki Okada, Brent Duncan, Phuonghanh Bui, Michael Yeshiambel, Brian Brown, Alan Handyside
Abstract The Refill Friction Spot Joining (RFSJ) is an emerging solid-state spot welding technology that thermo-mechanically creates a molecular-level bond between the work-pieces. RFSJ does not consume any filler or foreign materials so that no additional weight is introduced to the assembly. As the solid-to-liquid phase transition is not involved in RFSJ in general, there is no lack of fusion or material deterioration caused by liquefaction and solidification. Unlike the conventional friction stir spot welding, RFSJ produces a spot joint with a perfectly flush surface finish without a key or exit hole. Currently, the aerospace industry employs solid rivets for fastening the primary structures as they meet the baseline requirements and have well-established standards and specifications.
2016-09-27
Technical Paper
2016-01-8143
Jerry Syms, Theresia Manns, Björn Bergqvist
Abstract The noise generated by the flow of air past a transport truck is a key design factor for the manufacturers of these vehicles as the sound levels in the cabin are a significant component of driver comfort. This paper describes a collaboration between Volvo GTT and the National Research Council Canada to measure the in-cabin aeroacoustics of a full-scale cab-over tractor in the NRC 9 m Wind Tunnel. Acoustic instrumentation was installed inside the tractor to record cabin noise levels and externally to acquire tunnel background noise data. Using a microphone mounted on the driver’s-side tunnel wall as a reference to remove variations in background noise levels between data points, differences in cabin noise levels were able to be detected when comparing the tractor with different configurations. The good repeatability of the data allowed for differences of as little as 0.5 dB to be measured.
2016-09-20
Technical Paper
2016-01-2043
Richard C. Millar, Thomas Mazzuchi, Haflidi Jonsson
Abstract The SPA-10 project, sponsored by U.S. National Science Foundation, is to acquire and qualify a replacement for the retired T-28 “storm penetration” aircraft previously used to acquire meteorological data to enable understanding and modelling of mid-continent thunderstorms. The National Science Foundation selected the Fairchild A-10 (bailed from the U.S. Air Force) as the platform to be adapted to perform the storm penetration mission to altitudes of eleven kilometers, and funded Naval Postgraduate School’s Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) as prime contractor. An expert panel conducted a review of the SPA-10 project in 2014 and recommended a risk analysis addressing hazards to the aircraft and pilots, such as icing, hail, turbulence and lightning. This paper presents the results of the risk analysis performed in response to this need, including recommended mitigations.
2016-09-20
Technical Paper
2016-01-2035
Rudolf Neydorf, Anna Neydorf
Abstract The main difficulties of the mathematical models vehicles creation are defined by strongly nonlinearity of dependences which connect various variables their states and conditions of the movement environment. Most it belongs to aircrafts as aerodynamic interactions are characterized by essential nonlinearity up to discontinuity of variables and their derivatives. Creation process of these models is complicated by high-dimensionality, characteristic for the mechanical movement laws. Experimental creation of the mathematical models (MM) of such dependences is carried out by various mathematical methods of approximation of data. Universal remedies of the solution of the formulated task don't exist. Each of it possesses both benefits, and considerable shortcomings. In this regard the possibilities of a method creation of high-precision analytical approximations of the strongly nonlinear dependences using the analytical functions have been investigated.
2016-09-20
Technical Paper
2016-01-2034
Tobias Kreitz, Frank Thielecke
Abstract The aviation industry is facing major challenges due to increased environmental requirements that are driven by economic constraints. For this reason, guidelines like "Flightpath 2050", the official guide of European aviation, call for significant reductions in pollutant emissions. The concept of the More Electric Aircraft offers promising perspectives to meet these demands. A key-enabler for this concept is the integration of new technologies on board of the next generation of civil transportation aircraft. Examples are electro-mechanical actuators for primary and secondary flight controls or the fuel cell technology as innovative electrical energy supply system. Due to the high complexity and interdisciplinarity, the development of such systems is an equally challenging and time-consuming process.
2016-09-20
Technical Paper
2016-01-2031
Michal Sztykiel, Steven Fletcher, Patrick Norman, Stuart Galloway, Graeme Burt
Abstract There is a well-recognised need for robust simulation tools to support the design and evaluation of future More-Electric Engine and Aircraft (MEE/MEA) design concepts. Design options for these systems are increasingly complex, and normally include multiple power electronics converter topologies and machine drive units. In order to identify the most promising set of system configurations, a large number of technology variants need to be rapidly evaluated. This paper will describe a method of MEE/MEA system design with the use of a newly developed transient modeling, simulation and testing tool aimed at accelerating the identification process of optimal components, testing novel technologies and finding key solutions at an early development stage. The developed tool is a Matlab/Simulink library consisting of functional sub-system units, which can be rapidly integrated to build complex system architecture models.
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