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Viewing 1 to 30 of 4359
2016-09-27
Technical Paper
2016-01-2090
Sergey Lupuleac, Margarita Petukhova, Julia Shinder, Alexander Smirnov, Mariia Stefanova, Nadezhda Zaitseva, Tatiana Pogarskaia, Elodie Bonhomme
Perspective way of solving the problem of aircraft assembly optimization is global simulation of junction process using efficient numerical algorithms. Specialized software complex [1] was developed within the framework of cooperation between Airbus SAS and Saint Petersburg Polytechnic University. This tool allows engineers to simulate the aircraft assembly process and solve the number of tasks: • Calculation of resulting gap under given initial disposition of riveted parts and distribution of fastening elements; • Determination of fastening element pattern that provides sufficient quality of assembly; • Shimming prediction; • Evaluation of stresses caused by assembly. The tool is based on special approach that necessitates solving contact problem arising when aircraft parts are being joined. This problem can be described by several simplifying assumptions such as ommiting tangential displacements and friction from consideration and creating substructure for junction area.
2016-09-27
Technical Paper
2016-01-2105
Thomas G. Jefferson, Richard Crossley, Anthony Smith, Svetan Ratchev
This paper presents a novel reconfigurable assembly cell which can assemble multiple fuselage and wing variants. Most aerostructure assembly systems are designed to produce one variant only. For multiple variants, each assembly typically has a dedicated assembly cell, despite most assemblies requiring a process of drilling and fastening to similar tolerances. Assembly systems that produce more than one variant do exist but have long changeover or involve extensive retrofitting. Quick assembly of multiple products using one assembly system offers significant cost savings from reductions in NRC and lead time. Recent trends advocate Reconfigurable Assembly Systems (RAS) as a solution designed to have exactly the functionality necessary to produce a group of similar components. Components with similar geometries and processes are grouped into part families by iterating between design and manufacturing.
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
The Refill Friction Spot Joining (RFSJ) is an emerging solid-state spot welding technology that creates a molecular-level bond between the work-pieces through a thermo-mechanical processing. The RFSJ process 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 fusion lack 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
2016-01-2124
Sara Nilsson, Jonas Jensen, Mats Björkman, Erik Sundin
For the aerospace industry carbon fiber reinforced plastics (CFRP) is one of the fastest developing materials right now. The material has a strength-to-weight ratio that is several times higher than aluminium and steel, which makes it a great fit for applications where a low weight is crucial while maintaining strength and stiffness. It is specifically CFRP in pre-impregnated form, so called pre-preg, which has made its way into the aircrafts. Pre-preg is an anisotropic material that lets the designer control its properties to a high level of detail. Analogously to the material becoming used more widely in the aerospace industry the costs have decreased as the manufacturing methods have developed to follow the demands. However, how material and manufacturing method change the requirements and affect a product's design and performance can be hard to determine.
2016-09-27
Technical Paper
2016-01-2123
Matthias Busch
The integration of omega stringers to panels made of carbon fiber reinforced plastic (CFRP) by adhesive bonding, which are joined together in an autoclave, must be subject to high quality standards. Defects such as porosity, kissing bonds, voids or inclusion must be detected safely to guaranty the functionality of the component. Therefore, an inspection system is required to verify these bonds and detect different kinds of defects. In this contribution, the advantages of a robotic inspection system, which will be achieved through continuous testing, will be introduced. The testing method is the active thermography. The active thermography has major advantages compared with other non-destructive testing methods. Compared to testing with ultrasonic there is no coupling medium necessary, thus testing will be significantly enhanced.
2016-09-27
Technical Paper
2016-01-2112
Hilmar Apmann
As a new material FML made by aluminum foils and Glasfibre-Prepreg is a real alternative to common materials for fuselages of aircrafts. Since experiences within A380 this material has some really good advantages and becomes status as alternative to Aluminum and composite structures. Main goal for an industrial application for a higher production rates of aircrafts (like for single aisle) is the automation of production processes inside the process chain for FML-parts like skins and panels for fuselages. To reach these goals for high production rates first steps of automation inside this process chain have been developed in the last two years. Main steps is the automated lay-up of metallic foils and Glasfibre-Prepreg and also for integration of the bond film. Over this there are some more steps within positioning of i.e. stringers and doublers by automatic integration and shorter process chain to reduce process cost significantly.
2016-09-27
Technical Paper
2016-01-8138
Pranav Shinde, Ravi K, Nandhini Nehru, Sushant Pawar, Balaji Balakrishnan, Vinit Nair
Body in white forms a major structure in any automobile. It is responsible in providing structural rigidity to vehicle, safety, frame and a skeleton to support all body parts of vehicle. When it comes to judge the performance of vehicle, BIW is analyzed not only for its strength and shape but also weight. Light weight BIW structures have seen to be developed rapidly in order to fulfill requirement of best vehicle performance in dynamic conditions. Since then lot of efforts have been put into CAE, materials research, advanced manufacturing process and joining methods, each plays a critical role in BIW functionality. Constructional designing, development of light materials with improved strength and special manufacturing practices for BIW are few research areas with never ending questions. This paper attempts to review various factors studied for weight reduction and solutions provided so far. Some of the major findings are briefly discussed and suggestions are made for future research.
2016-09-27
Technical Paper
2016-01-8053
Adime Kofi Bonsi, Marius-Dorin Surcel
The objective of this project was to provide pertinent information on the performance of refrigerated and heated van semitrailers to help fleets make decisions that will improve efficiency and increase productivity. To achieve this objective, tests were designed to benchmark fuel consumption of reefers and heating units and measure the impact of trailer characteristics on fuel consumption of the unit for various temperature settings. The project compared older- to newer-design refrigerated van semitrailers to determine what potential fuel savings could be obtained while maintaining temperature control. The outcome of this project is a summary of the impact of trailer characteristics on fuel consumption. Additionally, a literature survey was conducted and best practices were identified.
2016-09-27
Technical Paper
2016-01-2095
Agata Suwala, Lucy Agyepong, Andrew Silcox
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 allow. 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
Technical Paper
2016-01-2120
David Judt, Kevin Forster, Helen Lockett, Craig Lawson, Philip Webb
In the civil aircraft industry there is a continuous drive to increase the production aircraft rate, particularly for single aisle aircraft where there is a large backlog of orders. One of the bottlenecks is the wing assembly process which is largely manual due to the complexity of the task and the limited accessibility. The presented work describes a general wing build approach for both structure and systems equipping operations. A modified build philosophy is then proposed, concerned with large component pre-equipping, such as skins, spars or ribs. The approach benefits from an offloading of the systems equipping phase and allowing for higher flexibility to organize the pre-equipping stations as separate entities from the overall production line. Its application is presented in the context of an industrial project focused on selecting feasible system candidates for a fixed wing design, based on assembly consideration risks for tooling, interference and access.
2016-09-20
Technical Paper
2016-01-1979
William D. Bertelsen
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
2016-01-2055
Koji Muraoka, Daisuke Hirabayashi, Masayuki Sato, Yoshihisa Aoki
We have been conducting a research on a future commercial tilt wing VTOL transport under JAXA(Japan Aerospace Exploration Agency)'s "Sky Frontier" Program aiming to develop technologies for aircraft innovation. The research focuses on the QTW (Quad Tilt Wing) civil VTOL transport, which features tandem tilt wings with propellers mounted at the mid-span of each wing. Unlike current and previous tail rotors and twin-engine tilt wings, the quad tilt wing configuration does not require a tail rotor or a main rotor mechanism and would have advantages in cruise performance and payload carrying performances over them. In our previous research, we had developed fundamental technologies of the QTW aircraft such as tandem tilt wing design procedure, flight mechanics modeling, transition flight controllers and so on.
2016-09-20
Technical Paper
2016-01-2019
Richard P. Johnston
The author recently presented a technical paper describing an advanced BWB air frame capable of transporting a 75-ton military cargo half-way around the world and back without re-fueling. This paper will look at the flight and range characteristics of that air frame modified to transport a 150-ton military cargo. Limited NASA open literature prop data from the Hamilton-Standard CRP-X1 high Mach 1986 UTC testing will be applied to characterize the counter-rotating prop performance. Air frame propulsion will be provided by 4 sets of C/R propellers driven by 8 separate Advanced Variable Cycle Diesel (AVCD) engines turbo-compounded to 14,000 SHP for take-off. Some discussion of the possible interactive aerodynamics of the highly loaded propeller sets at low Mach using a simplified disk-actuator explanation will be made. Mission table results of air frame and engine, prop and fuel consumption characteristics will be presented as the flight proceeds.
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
2016-01-1803
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
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
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.
2016-06-15
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
2016-01-1795
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
2016-01-1809
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.
2016-04-05
Technical Paper
2016-01-1349
Siddharth Bhupendra Unadkat, Suhas Kangde, Mahalingesh Burkul, Mahesh Badireddy
Abstract In the current scenario, the major thrust is to simulate the customer usage pattern and lab test using virtual simulation methods. Going ahead, prime importance will be to reduce the number of soft tool prototype for all tests which can be predicted in CAE. Automotive door slam test is significantly complex in terms of prediction through simulation. Current work focuses on simulating the slam event and deriving load histories at different mounting locations through dynamic analysis using LSDyna. These extracted load histories are applied to trimmed door Nastran model and modal transient analysis is performed to find the transient stress history. This approach has a significant advantage of less computation time and stress-convergence with Nastran for performing multiple design iterations compared to LSDyna. Good failure correlation is achieved with the test using this approach.
2016-04-05
Technical Paper
2016-01-1365
Siddharth Bhupendra Unadkat, Suhas Kangde, Mahalingesh Burkul, Mahesh Badireddy
Abstract The overall automotive industry is moving toward first time right test which in turn needs first time right analysis. This is due to the enormous pressure of cost, mass, time to market and availability of prototype vehicles for testing. Use of finite element methods enables to upfront predict the system behavior in operating conditions and evaluation of structural strength. In vehicle product development process, hood slam durability evaluation is one of the important tests for body closure structure. Current work showcases an effort made for developing virtual hood slam test. The virtual model consists of BIW, hood, hinge joint, interface like CRFM (cooling-radiator-fan module) and latch mechanism with spring preload. Analysis performed with LSDyna solver. An impact loading is applied by converting potential energy to kinetic energy, mimicking the hood dropping from a specified height on the hood latch.
2016-04-05
Technical Paper
2016-01-1380
S. Khodaygan, Amir Ghasemali, Hamed Afrasiab
Abstract One of the most important characteristics of industrial products, especially mechanical set-ups, is considering the tolerances of production and assembly of these set-ups, which directly influences the products’ operations. In sheet metal structures, due to the high flexibility of the sheets, the errors appeared while assembly will be as highly influential as the errors due to the production tolerance of the sheets. As a result, having a comprehensive model which could analyze the assembly process of these structures and also clarifies the relation between the tolerance of the parts and the ultimate changes of the set-up will be of considerable importance. During the assembly process, the contact effect between the components is inevitable. If such effect is not considered, the contact surfaces will permeate. The purpose of this paper is to present a method to analyze the tolerance of flexible sheet structures, considering the contact effect between surfaces.
2016-04-05
Technical Paper
2016-01-1384
Mengshi Deng, Jian Lan
Abstract Glass lifter is a key part of automobile door system. Guide rail is the carrier of glass lifter, and it bears various load cases when glass lifer works. Mass, stiffness and natural frequencies are the factors that influence the performance of glass lifter. In order to design a lighter and reasonable glass lifter, topology optimization methods are studied in this paper. In a rope-wheel glass lifter, design domain is determined by the mechanical structure and working conditions. Firstly, the single target continuum structure topology optimization mathematic models of guide rail are built in this paper, and analysis of multi-stiffness topology optimization are carried out accordingly in which volume fraction is set as 0.4, 0.5 and 0.6. These models are based on SIMP (Solid Isotropic Material with Penalization) theory.
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
2016-01-1532
Kyoungtaek Kwak, Seungwoo Seo, Randi Potekin, Antoine Blanchard, Alexander Vakakis, Donald McFarland, Lawrence Bergman
Abstract The purpose of this study is to develop a dynamic model that can accurately predict the motion of the door handle and counterweight during side impact crash tests. The door locking system, mainly composed of the door outside handle and door latch, is theoretically modeled, and it is assumed that the door outer panel can rotate and translate in all three directions during a side impact crash. Additionally, the numerical results are compared with real crash video footage, and satisfactory qualitative agreement is found. Finally, the simplified test rig that efficiently reflects the real crash test is introduced, and its operation is analyzed.
2016-04-05
Technical Paper
2016-01-1541
Zuolong Wei, Hamid Reza Karimi, Kjell Gunnar Robbersmyr
Abstract The analysis of the vehicle crash performance is of great meaning in the vehicle design process. Due to the complexity of vehicle structures and uncertainty of crashes, the analysis of vehicle crashworthiness is generally depending on the researchers' experiences. In this paper, different deformation modes of energy absorption components are studied. More specifically, the bumper, crash box, the front longitudinal beam and the engine/firewall have different frequency characteristics in the deformation process. According to these characteristics, it is possible to identify the performance of each component in the crash process of assembled structures. To achieve this goal, the crash response of the passenger cabin is decomposed by the time-frequency transformation. Different frequency components exist mainly in a specified period of the crash process.
2016-04-05
Technical Paper
2016-01-0022
Kenta Morishima, Shigeru Thomas Oho, Satoshi Shimada
Abstract A virtual power window control system was built in order to look into and demonstrate applications of microcontroller models. A virtual ECU simulated microcontroller hardware operations. The microcontroller program, which was written in binary digital codes, was executed step-by-step as the virtual ECU simulation went on. Thus, production-ready codes of ECUs are of primary interest in this research. The mechanical system of the power window, the DC motor to lift the window glass, the H-bridge MOSFET drivers, and the current sensing circuit to detect window locking are also modeled. This means that the hardware system of the control system was precisely modeled in terms of mechanical and circuit components. By integrating these models into continuous and discrete co-simulation, the power window control system was analyzed in detail from the microscopic command execution of the microcontroller to the macroscopic motion of the window mechanism altogether.
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.
Viewing 1 to 30 of 4359