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Viewing 91 to 120 of 4645
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
2016-01-8030
Dai Quoc Vo, Hormoz Marzbani, Mohammad Fard, Reza N. Jazar
Abstract As long as a tire steers about a titled kingpin pivot, the point coming in contact with the road moves along its perimeter. This movement affects the determination of kingpin moments caused by the tire forces, especially for large steering angles. The movement, however, has been neglected in the literature on the steerable-tire-kinematics-related topics. In this investigation, the homogeneous transformation is employed to develop a kinematic model of a steering tire in which the instantaneous ground-contact point on the tire is considered. The moments about the kingpin axis caused by tire forces are then computed based on the kinematics. A four-wheel-car model is constructed for determining the kingpin moment of steering system during the low-speed cornering maneuver. The result shows that the displacement of the ground-contact point along the tire perimeter is significant for large steering angles.
2016-09-27
Technical Paper
2016-01-8049
Keith Friedman, Khanh Bui, John Hutchinson, Matthew Stephens, Francisco Gonzalez
Abstract Frame rail design advances for the heavy truck industry provide numerous opportunities for enhanced protection of fuel storage systems. One aspect of the advanced frame technology now available is the ability to vary the frame rail separation along the length of the truck, as well as the depth of the frame. In this study, the effect of incorporating the fuel storage system within advanced technology tapered frame rails was evaluated using virtual testing under impact conditions. The impact performance was evaluated under a range of horizontal impacts conditions. The performance observed was quantified and then compared with previous testing of baseline diesel tank systems. Fuel storage system impact performance metrics over the range of crash conditions considered were quantified using virtual testing methods. The results obtained from the application of the impact performance evaluation methodology were then described.
2016-09-20
Technical Paper
2016-01-1979
William D. Bertelsen
Abstract Technology to create a VTOL for general aviation that is fast, efficient, easy to fly, and affordable, has proven elusive. Bertelsen Design LLC has built a large research model to investigate the potential of the arc wing VTOL to fulfill these attributes. The aircraft that is the subject of this paper weighs approximately 145 kg (320 lbs) and features coaxial, dual-rotating propellers, diameter 1.91 m (75 inches). Power is from an MZ 202 two-cycle, two-cylinder engine. Wingspan is 1.82 m (72 inches). The arc wing differentiates this aircraft from previous deflected-slipstream prototypes, which suffered from pitch-trim issues during transition. This paper will present configuration details of the Bertelsen model, showing how it is possible to generate high lift from a short-span wing system. The Bertelsen model can hover out of ground effect using just two arc-wing elements: a main wing and a “slat”.
2016-09-20
Technical Paper
2016-01-2019
Richard P. Johnston
Abstract An advanced composite Blended Wing Body (BWB) air frame previously used as a study aircraft to transport a 75-ton military cargo halfway around the world and back unrefueled has been modified and evaluated as a 150-ton heavy lifter. The modifications include enlarging the forward trim canard, reducing fuel load by 151,850 lbs, increasing the high-mach NASA-type counter-rotating propellers from 12 feet to 13 feet diameter, extending the propeller support pylons' height by 6 inches and modifying cruise flight and prop control strategies. Due to structural and propulsion system changes, the air frame Operational Empty Weight (OEW) was increased by 1,850 lbs. but the maximum Take Off Gross Weight (TOGW) was held to 800,000 lbs. Brief descriptions of the major propulsion system components are provided. In addition, a comparison of three different counter-rotating propeller systems is presented. The first is a Standard configuration.
2016-09-20
Technical Paper
2016-01-2046
Neno Novakovic
Abstract A Landing Gear Control and Actuation System (LGCAS) is one of the most complex aircraft systems. Due to the large landing gear masses and high performance requirements, aircraft hydraulic power with multiple hydraulic actuators and valves is used to provide system dynamic. LGCAS also requires a electrical source of energy for the electro-mechanical components, sensors and electronic control unit. For many years, correct fault isolation in a complex kinematic system, such as an aircraft landing gear actuation system, has been a great challenge with limited success. The fault isolation design challenge rests on the fact that landing gear control and actuation system has many so called “passive” components, whose basic function cannot be continuously monitored without additional sensors, transducers, and designated health monitoring equipment.
2016-09-20
Technical Paper
2016-01-2055
Koji Muraoka, Daisuke Hirabayashi, Masayuki Sato, Yoshihisa Aoki
Abstract JAXA (Japan Aerospace Exploration Agency) has been conducting a research on a future commercial tilt wing VTOL (Vertical TakeOff and Landing) transport under JAXA's "Sky Frontier" Program aiming to develop technologies for aircraft innovation. The research focuses on QTW (Quad Tilt Wing) civil VTOL transport, which features tandem tilt wings with propellers mounted at the mid-span of each wing. The goals of the research in the present phase are to propose a concept of a QTW business VTOL transport system and to pursue the essential technologies development such as OEI (One-Engine-Inoperative) safe recovery, transition flight control and cruise efficient aerodynamic design. Nine passengers business QTW concept was designed and trade-off analysis of the propulsion system architecture for OEI safety was conducted.
2016-09-20
Journal Article
2016-01-2013
Evgeni Ganev, Chiyuan Chiang, Leroy Fizer, Ed Johnson
Abstract This paper addresses the implementation of electric taxiing without the use of main engines by using electric propulsion of the landing gears. Substantial progress in this area has been achieved by Honeywell Aerospace and Safran in a joint initiative for developing an electric green taxiing system (eTaxi). Considerable analysis, design, fabrication, and testing have already been completed, which culminated in a demonstration at the Paris Air Show (PAS) in 2013. The eTaxi system has been installed on an A320 airplane that uses the auxiliary power unit (APU) to generate electric power to provide propulsion to two wheels of the main landing gear. The main advantages of such a system are reduction of fuel consumption and audio noise, reduction of CO2 , carbon and nitrous emissions, reduced engine foreign object damage (FOD) exposure and fast-turn time savings by elimination of the ground tractor for pushback operation.
2016-09-18
Technical Paper
2016-01-1917
Bongho Kim, Jeongkyu Kim, Kwang Yun Kim, Jung Hoon Woo
Abstract Creep groan noise occurs in a just moving vehicle by the simultaneous application of torque to the wheel and the gradual release of brake pressure in-vehicle. It is the low frequency noise giving the driver a very uncomfortable feeling. Recently, the field claims regarding the creep groan noise are increasing. So far, creep groan noise has been improved by means of chassis modification the transfer system. But vehicle body the response system does not. In this paper, the effect between vibration characteristics of vehicle body, creep groan noise was analyzed. Then presented analysis method for vehicle body effect regarding creep groan noise.
2016-06-15
Technical Paper
2016-01-1806
Sumon Sinha, Farokh Kavarana, Dan Williams, Kazuya Asao
Abstract A high performance rigid airfoil profile sunroof wind deflector has been developed for high speed freeway driving with the sunroof open. This deflector is clearly superior to the conventional bar type deflector and less expensive compared to tall flexible fabric mesh deflectors applied on high end vehicles today. It provides superior speech intelligibility under high speed driving with sunroof open. The criterion for designing this deflector was to get the highest airspeed possible to span the sunroof opening under all conditions. The customized shape also utilizes flow unsteadiness, including those at the onset of buffeting, in order to condition the shear layer. The airfoil profiled deflector yielded superior mid and high frequency acoustic performance with acceptable low frequency performance. A shorter airfoil deflector was sufficient to keep the external airflow from entering the forward tilted sunroof opening on a mid-size SUV under test.
2016-06-15
Technical Paper
2016-01-1849
Arnaud Caillet, Luca Alimonti, Anton Golota
Abstract The need for the industry to simulate and optimize the acoustic trim parts has increased during the last decade. There are many approaches to integrate the effect of an acoustic trim in a finite element model. These approaches can be very simple and empirical like the classical non-structural mass (NSM) combined to a high acoustic damping value in the receiver cavity to much more detailed and complex approach like the Poro-Elastic Materials (PEM) method using the Biot parameters. The objective of this paper is to identify which approach is the most appropriate in given situations. This article will first make a review of the theory behind the different methods (NSM, Impedances, Transfer Matrix Method, PEM). Each of them will be investigated for the different typical trim families used in the automotive industry: absorber, spring/mass, spring/mass/absorber.
2016-06-15
Technical Paper
2016-01-1830
Denis Blanchet, Luca Alimonti, Anton Golota
Abstract This paper presents new advances in predicting wind noise contribution to interior SPL in the framework of the Wind Noise German Working Group composed of Audi, Daimler, Porsche and VW. In particular, a new approach was developed that allows to fully describe the wind noise source using CFD generated surface pressure distribution and its cross-correlation function and apply this source on an SEA side glass. This new method removes the need to use a diffuse acoustic field or several plane waves with various incidence angle to approximate the correct acoustics source character to apply on the SEA side glass. This new approach results are compared with results previously published which use more deterministic methods to represent the side glass and the interior of a vehicle.
2016-06-15
Technical Paper
2016-01-1803
Hannes Frank, Claus-Dieter Munz
Avoiding narrowband components in the acoustic spectrum is one of the most critical objectives in the automotive aeroacoustic optimization process. The underlying physical mechanisms are not completely understood. In a preceding numerical and experimental investigation, we performed large eddy simulations of an early-development stage realistic side-view mirror, where tonal noise was captured and the principle mechanisms were identified. In this contribution, we present simulations on a simplified two-dimensional geometry that is based on these findings. It is shown that the basic flow topology relevant for tonal noise generation on the original side-view mirror as well as the tonal noise source is reproduced in the 2D case. Furthermore, we present comparisons with measurements and the necessity and influence of a splitter plate downstream of the 2D body to avoid large scale vortex shedding.
2016-06-15
Journal Article
2016-01-1801
Jonathan Vaudelle, Florian Godard, Florian Odelot, Anne Sanon
Abstract Acoustic comfort inside the vehicle is required whenever a wiper system is in function: front wiper motor noise is of great influence on the global comfort and its perception inside the car is 100% due to transmission of vibrations through wiper system fixation points on the vehicle. As any active source, both car manufacturer and system supplier need to be involved, at early stages of project development, in order to master the vibroacoustic integration of the system into the vehicle. This paper presents an experimental methodology dedicated to the front wiper system that offers the possibility to estimate the acoustic comfort inside the vehicle during project deployment phase, when modifications can still be proposed. Based on the XP-R-19701 standard, the procedure allows to measure, on a bench, the dynamic forces transmitted via the fixation points and details how to transpose them to the vehicle, taking into account the different specificities of the wiper system.
2016-06-15
Journal Article
2016-01-1809
Alexander Schell, Vincent Cotoni
Abstract Prediction of flow induced noise in the interior of a passenger car requires accurate representations of both fluctuating surface pressures across the exterior of the vehicle and efficient models of the vibro-acoustic transmission of these surface pressures to the driver’s ear. In this paper, aeroacoustic and vibro-acoustic methods are combined in order to perform an aero-vibro-acoustic analysis of a Mercedes-Benz A-class. The exterior aero-acoustic method consists of a time domain incompressible Detached Eddy Simulation (DES) and an acoustic wave equation. The method is extended in this paper to account for convection effects when modelling the exterior sound propagation. The interior vibro-acoustic model consists of a frequency domain Finite Element (FE) model of the side glass combined with a generalized Statistical Energy Analysis (SEA) model of the interior cabin.
2016-06-15
Journal Article
2016-01-1795
Charly Faure, Charles Pezerat, Frédéric Ablitzer, Jérôme Antoni
In this paper, a local method of structure-borne noise source characterization is presented. It is based on measurements of transverse displacement and local structural operator knowledge and allows to localize and quantify sources without any need of boundary condition information. To fix the instability caused by measurement noise, the regularization step inherent to inverse problem is realized with a probabilistic approach, within the Bayesian framework. When a priori distributions about noise and sources are considered as Gaussian, the Bayesian regularization is equivalent to the well-known Tikhonov regularization. The optimization of the regularization is then performed by the Gibbs Sampling (GS) algorithm, which is part of Markov Chain Monte Carlo (MCMC) techniques. The whole probability of the regularized solution is inferred, providing access to confidence intervals.
2016-06-15
Journal Article
2016-01-1825
Jung-Han Woo, Da-Young Kim, Jeong-Guon Ih
Abstract To hear the powerful and spectrally rich sound in a car is costly, because the usual car audio system adopts small loudspeakers. Also, the available positions of the loudspeakers are limited, that may cause the reactive effect from the backing cavity and the sound distortion. In this work, a part of the roof panel of a passenger car is controlled by array actuators to convert the specified large area to be a woofer. An analogous concept of the acoustic holography is employed to be projected as the basic concept of an inverse rendering for achieving a desired vibration field. The vibration of the radiating zone is controlled to be in a uniform phase, and the other parts outside it are to be made a no-change zone in vibration. The latter becomes a baffle for the woofer, and the backing cavity is virtually infinite if the sound radiation into the passenger cabin is only of concern.
2016-04-05
Technical Paper
2016-01-0240
Ruobing Zhan, Gangfeng Tan, Bo Yang, Zhiwei Zhang, Tie Wang, Cenyi Liu, Xintong Wu, Yanjun Ren, Haobo Xu
Abstract The Organic Rankine Cycle System (ORC) is an effective means to use the solar energy. The system adopts the solar energy on the car roof as the heat source to make the ORC work and drive the thermoelectric air-conditioner. It can improve the entering comfort on the parking condition and the vehicle energy utilization efficiency. In this research, the system comprehensively applied the principle of sunshine concentration, heat collection and photo electricity. Then considering the working condition and performance features of ORC system, the car roof was designed to have a compact structure, through which the efficiency of the solar vehicle system could be improved. Firstly, the research analyzed the heat source temperature and the heat flux impact on the output power of the ORC system. After that, the performance of heat collection was identified according to the given thermoelectric air-condition’s power requirements.
2016-04-05
Technical Paper
2016-01-0276
Mahalingesh Burkul, Hemant Bhatkar, Mahesh Badireddy, Narayanan Vijayakumar
Abstract In an automotive product development environment, identifying the premature structural failures is one of the important tasks for Body-In-White (BIW), sub-assemblies and components. The integrated car body structure i.e. monocoque structure, is widely used in passenger cars and SUVs. This structure is subjected to bending and torsional vibrations, due to dynamic loads. Normally the stresses due to bending are relatively small compared to stresses due to torsion in Body-In-White under actual road conditions [1]. This paper focuses on evaluating the life of Body-In-White structures subjected to torsional loading. An accelerated test method was evolved for identifying failure modes of monocoque BIW by applying torsion fatigue. The observation of the crack generation and propagation was made with respect to a number of torsion fatigue cycles.
2016-04-05
Technical Paper
2016-01-0351
Yuki Kudo, Akinori Sato, Kazutaka Kimura, Shoichi Iwamoto, Hiroyuki Ohba, Motoya Sakabe, Yasuhiro Shirai
Abstract Replacing the metal car roof with conventional solar modules results in the increase of total car weight and change of center of mass, which is not preferable for car designing. Therefore, weight reduction is required for solar modules to be equipped on vehicles. Exchanging glass to plastic for the cover plate of solar module is one of the major approaches to reduce weight; however, load bearing property, impact resistance, thermal deformation, and weatherability become new challenges. In this paper a new solar module structure that weighs as light as conventional steel car roofs, resolving these challenges is proposed.
2016-04-05
Technical Paper
2016-01-0511
Na Qiu, Yunkai Gao, Jianguang Fang, Shanshan Wang
Abstract As a potential material for lightweight vehicle, polymethyl methacrylate (PMMA) has proven to perform well in optical behavior and weather resistance. However, the application in automotive glazing has seldom been studied. This paper investigates the defrost performance of PMMA rear window using both numerical and experimental methods. The finite element analysis (FEA) results were found to be in good agreement with the experimental data. Based on the validated finite element model, we further optimized the defrost efficiency by changing the arrangement of heating lines. The results demonstrated the frost layer on the vision-related region of PMMA rear window can melt within 30 minutes, which meets the requirement of defrost efficiency.
2016-04-05
Technical Paper
2016-01-0391
Tanmay Sushant Santra, Vikas Kumar Agarwal, Mihir Bhambri
This paper depict the difference in the endurance factor of safety with usage of static and quasi static FE analysis and corrective measures take to solve the problem. The importance of the dynamic loading and subsequent effect of it on the multi axial fatigue analysis. Considering the modern trend prevailing among the vehicle manufacturers and specifically talking about two wheeler industry, it is clear that while the engine remains the same but the frame is changed to cater the market with new models to cut down on the development time. Initially the crankcase was designed for a double cradle frame where the crankcase was mounted on the frame. Later, the frame design was changed to single cradle where engine acts as a stress member link. This kind of arrangement makes the crankcase mountings participate in the chassis loads. Therefore, the crankcase mounting experiences road loads when the vehicle encounter the road irregularities.
2016-04-05
Technical Paper
2016-01-0406
Akihiko Asami, Tomoyuki Imanishi, Yukio Okazaki, Tomohiro Ono, Kenichi Tetsuka
Abstract High-tensile steel plates and lightweight aluminum are being employed as materials in order to achieve weight savings in automotive subframe. Closed-section structures are also in general use today in order to efficiently increase parts stiffness in comparison to open sections. Aluminum hollow-cast subframe have also been brought into practical use. Hollow-cast subframe are manufactured using sand cores in gravity die casting (GDC) or low-pressure die casting (LPDC) processes. Using these manufacturing methods, it is difficult to reduce product thickness, and the limitations of the methods therefore make the achievement of weight reductions a challenge. The research discussed in this paper developed a lightweight, hollow subframe technology employing high-pressure die casting (HPDC), a method well-suited to reducing wall thickness, as the manufacturing method. Hollow-casting using HPDC was developed as a method of forming water jackets for water-cooled automotive engines.
2016-04-05
Technical Paper
2016-01-0397
Wenxin Qin, Sandip Datta, Weidong Zhang
Abstract In automotive FEA analysis, there are many components or assemblies which can be simplified to two-dimensional (2D) plane or axisymmetric analytical problems instead of three-dimensional (3D) simulation models for quick modeling and efficient analysis to meet the timing in the design development process, especially in the advanced design phase and iteration studies. Even though some situations are not perfectly planar or axisymmetric problems, they may still be approximated in 2D planar or axisymmetric models, achieving results accurate enough to meet engineering requirements. In this paper, the authors have presented and summarized several complex 3D analytical situations which can be replaced by simplified plane axisymmetric models or 2D plane strain analytical models.
2016-04-05
Technical Paper
2016-01-0350
Andre Camboa, Bernardo Ribeiro, Miguel Vaz, Luis Pinheiro, Ricardo Malta
The development of an automotive hood for an electric vehicle based on a polymer-metal hybrid configuration is described in this paper. Here, special focus is given only to the engineering design and prototyping phases which are the initial stages of a much bigger project. A project that aims to evaluate the cost efficiency, weight penalty and structural integrity of adopting polydicyclopentadiene as an exterior body material in low production volume vehicles, among them the electric ones. For the engineering design and prototyping phases, three different reinforcement geometries were developed and six mechanical simulations were done through finite element analysis to aid best frame geometry selection and optimization. The entire hood was then prototyped containing the optimized geometry. The fabrication of the frame was made through metal stamping and the exterior panel through reaction injection moulding. Adhesive bonding was used for its assembly.
2016-04-05
Technical Paper
2016-01-1612
Francesco Mariani, Francesco Risi, Nicola Bartolini, Francesco Castellani, Lorenzo Scappaticci
Abstract Aerodynamics is one of the most important factors in the development of racing cars. At the speeds of formula cars reach the formula cars, the driver's neck can be subjected to stresses resulting from the aerodynamic forces acting on the helmet; developing an aerodynamic project that takes into account the comfort of the driver without affecting performance is certainly considered a challenging activity. The aim of the present work is to develop a low-pitching-momenthelmet for formula racing cars optimizing the shape and location, applying some aerodynamic appendices. This goal is pursued by adopting an approach based on both experimental and numerical activities. First, the aerodynamic configuration of an existing helmet was examined; through a testing campaign in the wind tunnel facilities of Perugia University, pressures acting on the helmet were scanned at various speeds and data about aerodynamic drag were collected.
2016-04-05
Technical Paper
2016-01-0256
Hideaki Nagano, Kenji Tomita, Yasuhiro Tanoue, Yuji Kobayashi, Itsuhei Kohri, Shinsuke Kato
Abstract In the winter, windshield glass fogging must be prevented through the intake of outdoor air into a vehicle. However, the corresponding energy loss via the ventilation system cannot be ignored. In the present study, the defogging pattern on the windshield is evaluated and the water vapor transportation in the flow field in the vehicle is analyzed in order to investigate the ventilation load by means of a numerical simulation. Some examined cases involve new outlet positions. Additionally, a new, energy-saving air supply method for defogging, with so-called “double-layer ventilator”, is proposed. In this method, one air jet layer is obtained via a conventional defogging opening in the vicinity of the windshield, supplying an outdoor air intake. The other jet consists of recirculated air that covers the outdoor air, preventing it from mixing with the surrounding air.
2016-04-05
Technical Paper
2016-01-0372
Thomas Thesing, Neil Bishop
Abstract Conventional approaches for the fatigue life evaluation of automotive parts like headlamps involves the evaluation of random stress conditions in either the time or frequency domain. If one is working in the frequency domain the fatigue life can be evaluated using one of the available methods like the Rayleigh (Narrow Band) approach or the more recent Dirlik method. Historically, the random stresses needed as input to these methods have been evaluated by the FEA solver (eg Abaqus, or Nastran) and these “in built” stress evaluations have limitations which relate to the fact that the stress conditions are complex and so the common “equivalents” for stress like von-Mises or Principal have not been available. There have also been limitations in the location and method of averaging for such stresses. In addition, the fatigue calculation approach for doing the evaluation has been constrained to the linear stress based (S-N) method.
2016-04-05
Technical Paper
2016-01-0526
Sumiran Manghani, Girish Kumar
Abstract Vehicle performance is highly dependent on the design and material used. Fairing of a Human Powered Vehicle (HPV) is responsible for the reduction in the aerodynamic drag force and its material determines the overall weight and the top speed of the vehicle. Selection of material for fairings depends on various physical, mechanical and manufacturing properties along with practical considerations like availability of material. Today, an ever-increasing variety of composite materials and polymers are available, each of them possessing their own characteristics, applications, advantages and limitations. Many automotive composites are used for manufacturing fairings. Materials like Carbon fiber, Glass fiber (E glass, S glass), Aramid fiber (Kevlar 29, Kevlar 49) are some of the viable options that have been used in the past for manufacturing fairing of HPVs.
2016-04-05
Technical Paper
2016-01-0246
Rupesh Sonu Kakade, Prashant Mer
Abstract Vehicle occupants, unlike building occupants, are exposed to continuously varying, non-uniform solar heat load. Automotive manufacturers use photovoltaic cells based solar sensor to measure intensity and direction of the direct-beam solar radiation. Use of the time of the day and the position - latitude and longitude - of a vehicle is also common to calculate direction of the direct-beam solar radiation. Two angles - azimuth and elevation - are used to completely define the direction of solar radiation with respect to the vehicle coordinate system. Although the use of solar sensor is common in today’s vehicles, the solar heat load on the occupants, because of their exposure to the direct-beam solar radiation remains the area of in-car subjective evaluation and tuning. Since the solar rays travel in parallel paths, application of the ray tracing method to determine solar insolation of the vehicle occupants is possible.
Viewing 91 to 120 of 4645