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Viewing 1 to 30 of 14893
2016-06-15
Journal Article
2016-01-1819
Antonio J. Torregrosa, Alberto Broatch, Vincent Raimbault, Jerome Migaud
Abstract Intake noise has become one the main concerns in the design of highly-supercharged downsized engines, which are expected to play a significant role in the upcoming years. Apart from the low frequencies associated with engine breathing, in these engines other frequency bands are also relevant which are related to the turbocharger operation, and which may radiate from the high-pressure side from the compressor outlet to the charge air cooler. Medium frequencies may be controlled with the use of different typologies of resonators, but these are not so effective for relatively high frequencies. In this paper, the potential of the use of multi-layer porous materials to control those high frequencies is explored. The material sheets are located in the side chamber of an otherwise conventional resonator, thus providing a compact, lightweight and convenient arrangement.
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
2016-01-1847
Olivier Robin, Celse Kafui Amedin, Alain Berry, Noureddine Atalla, Olivier Doutres, Franck Sgard
A method for estimating the sound absorption coefficient of a material under a synthesized Diffuse Acoustic Field was recently proposed, as an alternative to classical sound absorption measurements in reverberant rooms (Robin O., Berry A., Doutres O., Atalla N., ‘Measurement of the absorption coefficient of absorbing materials under a synthesized diffuse acoustic field’, J. Acoust. Soc. Am., 136 (1) EL13-EL19, 2014). Using sound field reproduction approaches and a synthetic array of acoustic monopoles facing the material, estimation of the sound absorption coefficient under a reproduced Diffuse Acoustic Field in a hemi-anechoic room was shown to be feasible. The method was successfully tested on a few samples of melamine foam of close thicknesses and areas, but the influence of several parameters such as the source height, or the samples dimensions together with the nature of the porous material was not fully investigated.
2016-06-15
Technical Paper
2016-01-1848
Jean-Loup Christen, Mohamed Ichchou, Olivier Bareille, Bernard Troclet
Abstract The problem of noise transmission through a structure into a cavity appears in many practical applications, especially in the automotive, aeronautic and space industries. In the mean time, there is a trend towards an increasing use of composite materials to reduce the weight of the structures. Since these materials usually offer poor sound insulation properties, it is necessary to add noise control treatments. They usually involve poroelastic materials, such as foams or mineral wools, whose behaviour depends on many parameters. Some of these parameters may vary in rather broad ranges, either because of measurement uncertainties or because their values have not been fixed yet in the design process. In order to efficiently design sound protections, performing a sensitivity analysis can be interesting to identify which parameters have the most influence on the relevant vibroacoustic indicators and concentrate the design effort on them.
2016-06-15
Technical Paper
2016-01-1851
Arnaud Duval, Minh Tan Hoang, Valérie Marcel, Ludovic Dejaeger
Abstract The noise treatments weight reduction strategy, which consists in combining broadband absorption and insulation acoustic properties in order to reduce the weight of barriers, depends strongly on surface to volume ratio of the absorbing layers in the reception cavity. Indeed, lightweight technologies like the now classical Absorber /Barrier /Absorber layup are extremely efficient behind the Instrument Panel of a vehicle, but most of the time disappointing when applied as floor insulator behind the carpet. This work aims at showing that a minimum of 20 mm equivalent “shoddy” standard cotton felt absorption is requested for a floor carpet insulator, in order to be able to reduce the weight of barriers. This means that a pure absorbing system that would destroy completely the insulation properties and slopes can only work, if the noise sources are extremely low in this specific area, which is seldom the case even at the rear footwells location.
2016-06-15
Technical Paper
2016-01-1850
Christian Thomas, Nouredine Atalla
In passenger aircraft the most important noise control treatment is the primary insulation attached to the fuselage. Next to its acoustic properties the primary insulation main purpose is the thermal insulation and the minimization of condensed water. In general it consists of fibrous materials like glass wool wrapped in a thin foil. Due to stringent flame, smoke and toxicity requirements the amount of available materials is limited. Furthermore the amount of material installed in aircraft per year is much smaller compared to needs in the automotive industry. Therefore the best lay-up of the available materials is needed in terms of acoustics. This paper presents a tool for numerical optimization of the sound insulation package. To find an improved insulation the simulation tool is used in interaction with a measurement database. The databank is constructed from aircraft grade materials such as fibrous materials, foams, resistive screens and impervious heavy layers.
2016-06-15
Journal Article
2016-01-1852
Ehsan Fatourehchi, Vishak Elisaus, Mahdi Mohammadpour, Stephanos Theodossiades, Homer Rahnejat
Abstract Efficiency and durability are key areas of research and development in modern racing drivetrains. Stringent regulations necessitate the need for components capable of operating under highly loaded conditions whilst being efficient and reliable. Downsizing, increasing the power-to-weight ratio and modification of gear teeth geometry to reduce friction are some of the actions undertaken to achieve these objectives. These approaches can however result in reduced structural integrity and component durability. Achieving a balance between system reliability and optimal efficiency requires detailed integrated multidisciplinary analyses, with the consideration of system dynamics, contact mechanics/tribology and stress analysis/structural integrity. This paper presents an analytical model to predict quasi-static contact power losses in lubricated spur gear sets operating under the Elastohydrodynamic regime of lubrication.
2016-06-15
Journal Article
2016-01-1788
Charles Pezerat
Abstract Identification of vibration sources, defects and/or material properties consists generally in solving inverse problems. The called RIFF method (French acronym meaning Windowed and Filtered Inverse Solving) is one way to solve this kind of inverse problem. The basic principle of the RIFF approach consists in measuring vibration displacement on a meshgrid in a local area of interest, injecting measured data in the motion equation and calculating the searched unknown. Compared to other usual inverse techniques, the RIFF method has the curious particularity of needing the knowledge of the local motion equation only. Boundary conditions, sources or dynamic behaviors outside the area of interest can be completely ignored, whereas they are required for the direct problem solving. The searched unknown can then be identified locally with respect to the frequency and can be mapped by using a scanning process of the area of interest.
2016-06-15
Journal Article
2016-01-1791
Noé F. Melo, Claus Claeys, Elke Deckers, Bert Pluymers, Wim Desmet
Abstract The NVH performance of conventional panels and structures is mainly driven by their mass. Silence often requires heavy constructions, which conflicts with the emerging trend towards lightweight design. To face the challenging and often conflicting task of merging NVH and lightweight requirements, novel low mass and compact volume NVH solutions are required. Vibro-acoustic metamaterials with stopband behavior come to the fore as possible novel NVH solutions combining lightweight requirements with superior noise and vibration insulation, be it at least in some targeted and tunable frequency ranges, referred to as stopbands. Metamaterials are artificial materials or structures engineered from conventional materials to exhibit some targeted performance that clearly exceeds that of conventional materials. They consist typically of (often periodic) assemblies of unit cells of non-homogeneous material composition and/or topology.
2016-06-15
Technical Paper
2016-01-1792
Aurélien Lonni, Olivier Tanneau
Abstract Nowadays, downsizing and turbochargers are more frequently used, mostly for petrol engines. It can lead to an increase of NVH issues related to the turbos, such as the hiss noise propagation in the air ducts. Hutchinson, among all its activities, supplies rubber and plastic parts for the car industry, especially in fluid management systems. The turbocharger’s airborne noise issue has now been tackled for ten years by implementing acoustic devices in the line and providing solutions to car manufacturers with our hot-side rubber ducts. In this paper, will be first presented the main HP air loop NVH issues, and then explained an approach to design technical solutions. Generally speaking, the noise propagates inside the hot side air hoses, crosses the weakest parts of the system by acoustic emissivity to reach finally the driver and passengers’ ears.
2016-06-15
Technical Paper
2016-01-1776
Alexander Rabofsky, Alexander Koeck, Martin Mittermaier
Abstract Lightweight vehicle design causes special demands for functional NVH design. The reduction of weight by reducing material thickness, enabled by new alloys, the combination of materials and new materials increases the sensitivity of a vehicle body to the vibrational and acoustical response of external forces like powertrain or road and wind excitation. To be able to fully raise lightweight potentials design has to be driven closer to functional boundaries, putting higher demands on the accuracy of the prediction by simulation. For a robust design a very broad view on several loadcases is needed to make sure that by optimization on one target no other target is violated. In this paper, optimization strategies for complex NVH load-cases should be investigated in detail. In reality, load-cases, excitations as well as boundary conditions are very often complex and complicated.
2016-06-15
Technical Paper
2016-01-1856
Hannes Allmaier, Günter Offner
Abstract Elastohydrodynamic (EHD)-simulation is a widely applied simulation technique that is used in a very diverse field of applications ranging from the study of vibroacoustics to the calculation of friction power losses in lubricated contacts. In particular, but not limited to, the automotive industry, technical advances and new requirements put current EHD simulation methodology under test. Ongoing trends like downsizing, downspeeding, start-stop and the continuing demand for increasing fuel efficiency impose new demands and challenges also on the simulation methodology. Increasing computational capabilities enable new simulation opportunities on the other hand. In the following, an overview is given on the current state of the art and today’s challenges for the elastohydrodynamic simulation of journal bearings and their wide range of applications from highly loaded main bearings supporting the crank shaft in the ICE to high speed turbocharger bearings.
2016-04-11
Journal Article
2016-01-9081
Sean A. McKelvey, Yung-Li Lee
Abstract Multiaxial loading on mechanical products is very common in the automotive industry, and how to design and analyze these products for durability becomes an important, urgent task for the engineering community. Due to the complex nature of the fatigue damage mechanism for a product under multiaxial state of stresses/strains which are dependent upon the modes of loading, materials, and life, modeling this behavior has always been a challenging task for fatigue scientists and engineers around the world. As a result, many multiaxial fatigue theories have been developed. Among all the theories, an existing equivalent stress theory is considered for use for the automotive components that are typically designed to prevent Case B cracks in the high cycle fatigue regime.
2016-04-05
Journal Article
2016-01-1198
Pascal Schmalen, Peter Plapper, Wayne Cai
Abstract Laser welding of dissimilar metals such as Aluminum and Copper, which is required for Li-ion battery joining, is challenging due to the inevitable formation of the brittle and high electrical-resistant intermetallic compounds. Recent research has shown that by using a novel technology, called laser braze-welding, the Al-Cu intermetallics can be minimized to achieve superior mechanical and electrical joint performance. This paper investigates the robustness of the laser braze-welding process. Three product and process categories, i.e. choice of materials, joint configurations, and process conditions, are studied. It is found that in-process effects such as sample cleanness and shielding gas fluctuations have a minor influence on the process robustness. Furthermore, many pre-process effects, e.g. design changes such as multiple layers or anodized base material can be successfully welded by process adaption.
2016-04-05
Technical Paper
2016-01-1088
Julio Carrera
Abstract The increasingly restrictive emission standards in the automotive industry require higher thermal requirements in the EGR loop in terms of gas mass flow, gas temperature and lower coolant flow rate. Also, their performance has to be sustained over a longer period of time. Therefore, thermal load for EGR components, especially EGR coolers, has been increased and thermal fatigue durability is now a critical issue during their development. One of the most challenging issues during product validation is to define a thermal fatigue test with the same field cumulative fatigue damage in order to guarantee durability during vehicle life. A new analytical procedure has been developed in order to define the equivalent thermal fatigue test which has the same cumulative damage as the real application in the field or to estimate durability in the field on the basis of a previous thermal fatigue test result.
2016-04-05
Technical Paper
2016-01-1085
Ming Chen, Yanjun Wang, Wenrui Wu, Quan Cui, Kai Wang, Lingfang Wang
Abstract The present paper describes a CAE analysis approach to evaluate the thermal-mechanical fatigue (TMF) of the cylinder head of a turbo charged GDI engine with integrated exhaust manifold. It allows design engineers to identify structural weakness at the early stage or to find the root cause of cylinder head TMF failures. At SAIC Motor, in test validation phase a newly developed engine must pass a strict durability test on test bed under thermal cycling conditions so that the durability characteristics can be evaluated. The accelerated dynamometer test is so designed that it gives equivalent cumulative damage as what would occur in the field. The duty cycle includes rated speed full load, rated speed motored and idle speed conditions. A transient none-linear finite element method is used to calculate the plastic deformation and thermal mechanical behaviors of the cylinder head assembly during thermal cycling.
2016-04-05
Technical Paper
2016-01-1575
Federico Ballo, Roberto Frizzi, Gianpiero Mastinu, Donato Mastroberti, Giorgio Previati, Claudio Sorlini
Abstract In this paper the lightweight design and construction of road vehicle aluminum wheels is dealt with, referring particularly to safety. Dedicated experimental tests aimed at assessing the fatigue life behavior of aluminum alloy A356 - T6 have been performed. Cylindrical specimens have been extracted from three different locations in the wheel. Fully reversed strain-controlled and load-controlled fatigue tests have been performed and the stress/strain-life curves on the three areas of the wheel have been computed and compared. The constant amplitude rotary bending fatigue test of the wheel has been simulated by means of Finite Element method. The FE model has been validated by measuring the strain at several points of the wheel during the actual test. From the FE model, the stress tensor time history on the whole wheel over a loading cycle has been extracted.
2016-04-05
Technical Paper
2016-01-1538
Vaibhav V. Gokhale, Carl Marko, Tanjimul Alam, Prathamesh Chaudhari, Andres Tovar
Abstract This work introduces a new Advanced Layered Composite (ALC) design that redirects impact load through the action of a lattice of 3D printed micro-compliant mechanisms. The first layer directly comes in contact with the impacting body and its function is to prevent an intrusion of the impacting body and uniformly distribute the impact forces over a large area. This layer can be made from fiber woven composites imbibed in the polymer matrix or from metals. The third layer is to serve a purpose of establishing contact between the protective structure and body to be protected. It can be a cushioning material or a hard metal depending on the application. The second layer is a compliant buffer zone (CBZ) which is sandwiched between two other layers and it is responsible for the dampening of most of the impact energy.
2016-04-05
Technical Paper
2016-01-0920
Bradford A. Bruno, Ann M. Anderson, Mary Carroll, Thomas Swanton, Paul Brockmann, Timothy Palace, Isaac A. Ramphal
Abstract Aerogels are nanoporous structures with physical characteristics that make them promising for use in automotive exhaust catalysis systems: highly porous with low densities (<0.1 g/mL) and high surface area per unit mass (>300 m2/g) - features that provide favorable characteristics for catalysis of gaseous pollutants. Ceramic aerogels are also highly thermally insulating (∼0.015 W/mK) and able to withstand high temperatures. Aerogels can be made of a wide variety of ceramics (e.g. alumina, silica, titania) with other catalytically active metals (e.g. copper, cobalt, nickel) incorporated into their structures. This paper provides a brief overview of the rapid supercritical extraction (RSCE) method employed in this work for aerogel preparation, describes in detail the benchtop scale testbed and methods used to assess the catalytic activity of RSCE fabricated aerogels, and presents data on the catalytic ability of some promising aerogel chemistries.
2016-04-05
Technical Paper
2016-01-1016
Yolanda Bravo, Carmen Larrosa, Jose Lujan, Héctor Climent, Manuel Rivas
Abstract Spark ignition (SI) engines are increasing their popularity worldwide since compression ignition (CI) engines have been struggling to comply with new pollutant emission regulations. At the moment, downsizing is the main focus of research on SI engines, decreasing their displacement and using a turbocharging system to compensate this loss in engine size. Exhaust gas recirculation is becoming a popular strategy to address two main issues that arise in heavily downsized turbocharged engines at full load operation: knocking at low engines speeds and fuel enrichment at high engine speeds to protect the turbine. In this research work, a fuel consumption optimization for different operating conditions was performed to operate with a cooled EGR loop, with gasoline and E85. Thus, the benefits of exhaust gas recirculation are proven for a SI gasoline turbocharged direct injection engine.
2016-04-05
Technical Paper
2016-01-1331
Shingo Hanano, Kanehiro Nagata, Yusuke Murase
Abstract The need to add more color variations to the traditional black gloss has increased globally in recent years. The intention is for automobile manufacturers to differentiate their products in terms of appearance design. The most noticeable trend is to add embellishment around the front grill. The same trend can be seen in the areas around vehicle doors. It is most common to use a coating material to emphasize the black gloss. However, in overseas countries it is a challenge to meet the required appearance quality, and under the current circumstances CKD is imported from Japan to meet such requirements. Recently, a new film-transfer technique has been established that can express black gloss as well as any coating material by transferring the roughness of the film surface. It is achieved by crimping the PET film onto the vinyl-chloride surface after the extrusion molding is performed. Moreover, we have successfully localized this technique and reduced the manufacturing cost.
2016-04-05
Technical Paper
2016-01-1329
Fulin Wei, Yanhua Shen, Tao Xu
Abstract Off-road dump truck body is exposed to abrasive wear during handling of granular materials. The wear rate of body of dump truck has direct influence on maintenance and replacement during its service process. In this paper the discrete element method (DEM) is used to simulate the granular materials of dump truck. The wear of body floor during one dumping process can be achieved by cosimulation of FEM-DEM. The wear depth variation of body has the stochastic characteristic which can be modeled by Geometric Brownian Motion (GBM). The two parameters in the stochastic differential equation, drift coefficient and diffusion coefficient, can be estimated by the wear depth measuring data. It is possible to quantitatively predict the wear evolution of every grid point of the body floor by solving this stochastic differential equation. The simulation result of the wear model is helpful to optimize design of off-road dump truck body.
2016-04-05
Technical Paper
2016-01-1332
Fredrik Henriksson, Kerstin Johansen
Abstract In the automotive industry, mass reduction and lightweight design is a continuing trend that does not show signs of declining. When looking at where to reduce weight in a vehicle, the body is a preferential subsystem due to its large contribution to overall mass and the stability of body composition over a specific model range. The automotive industry of today moves toward a greater differentiation in materials that compose a car, which can be seen in the several different multi material vehicle bodies that have been introduced by manufacturers in recent years. But while mixing materials may contribute to a good compromise between weight reduction and vehicle cost, it also proposes a number of challenges that need to be addressed. Among other material factors, the different coefficients of thermal expansions might introduce new stresses during painting and curing.
2016-04-05
Journal Article
2016-01-1344
Koushi Kumagai, Masaaki Kuwahara, Tsuyoshi Yasuki, Norimasa Koreishi
Abstract This paper describes the development of a fracture finite element (FE) model for laser screw welding (LSW) and validation of the model with experimental results. LSW was developed and introduced to production vehicles by Toyota Motor Corporation in 2013. LSW offers superb advantages such as increased productivity and short pitch welding. Although the authors had previously developed fracture FE models for conventional resistance spot welding (RSW), a fracture model for LSW has not been developed. To develop this fracture model, many comprehensive experiments were conducted. The results revealed that LSW had twice as many variations in fracture modes compared to RSW. Moreover, fracture mode bifurcations were also found to result from differences in clearance between welded plates. In order to analyze LSW fracture phenomena, detailed FE models using fine hexahedral elements were developed.
2016-04-05
Technical Paper
2016-01-1351
Simhachalam Bade
Abstract Aluminum alloys are widely used in the transportation because of their high strength-to-weight ratio and outstanding capability in absorbing energy. In this paper, performance of bumper with crash tubes using aluminum alloy AA7003 materials is compared with that of AA6061 and high strength steel (DP800) using numerical methods. Quasi-static test is simulated using the LS-DYNA implicit finite element program. Bumper and crash tubes are included in the finite element model. Symmetric Holes are provided in the crash tubes to initiate crushing. The energy absorbed by bumper and crash tubes are compared. Dynamic simulation is done using LS-Dyna explicit program. True stress-true plastic strain curves at different strain rates from the literature is used in the dynamic simulation of AA7003 material to study the strain rate effects on impact behavior of tubes. The impact mass is represented by RigidWall Planar Moving Force option in LSDYNA.
2016-04-05
Technical Paper
2016-01-1275
Ganesh Duraisamy, Nagarajan Govindan, P. Shanmugam
Biodiesel obtained by transesterification process from the fatty leather waste (tannery waste water) was blended with Diesel in various proportions and it was tested in a single cylinder, naturally aspirated, direct injection (DI) Diesel engine of rated power 4.4 kW at the rated speed of 1500 rpm. Experiments were conducted with B10, B20, B30, B40 and B50 blends and their combustion, performance and emission characteristics were studied in comparison with conventional Diesel fuel. The experimental results show an increase in brake thermal efficiency with biodiesel blends compared to neat Diesel operation. Reduced ignition delay and combustion duration is observed for B30 blend compared to Diesel. The oxides of nitrogen emissions are significantly lower for B10 and B20 blends compared to Diesel operation, whereas with remaining blends the NOx emissions are increased compared to Diesel fuel.
2016-04-05
Journal Article
2016-01-0104
Khalil Maalouf, David Stull, Keith Nicholas
Abstract In copper wire, real time crimp monitoring has traditionally been based on force measurement during the crimp cycle. The force attributed to molding the copper wire into the terminal is a significant portion of the total force needed to form the crimp. Therefore, any wire deviation from the norm is translated into a force pattern aberration that can be detected using basic signal pattern analysis. As the mobility industry is contemplating replacing copper with aluminum wire, in order to save on weight and material cost, the traditional force monitoring becomes ineffective in detecting wire faults in the crimp. The reason is that aluminum is softer than copper, and most of the force exerted during the crimp cycle is consumed by forming the copper terminal itself. The small force deviation due to an aluminum wire fault becomes much more difficult to detect. Therefore, a new technique is needed to monitor crimped aluminum wires.
2016-04-05
Technical Paper
2016-01-0141
Prasanna Vasudevan, Sreegururaj Jayachander
Abstract Several studies in the field of hedonics using subjective responses to gauge the nature and influence of odors have attempted to explain the complex psychological and chemical processes. Work on the effect of odors in alleviating driver fatigue is limited. The potential to improve road safety through non-pharmacological means such as stimulating odors is the impetus behind this paper. This is especially relevant in developing countries today with burgeoning economies such as India. Longer road trips by commercial transport vehicles with increasingly fatigued drivers and risk of accidents are being fuelled by distant producer - consumer connections. This work describes a two stage comparative study on the effects of different odors typically obtainable in India. The stages involve administration of odorants orthonsally and retronasally after the onset of circadian fatigue in test subjects. This is followed by a small cognitive exercise to evaluate hand-eye coordination.
2016-04-05
Technical Paper
2016-01-0229
Mohammed Ismail, Shahram Fotowat, Amir Fartaj
Abstract A numerical study is performed to investigate the transient heat transfer and flow characteristics of aluminum oxide (Al2O3) nanoparticles dispersed in 50:50 ethylene glycol/water (EG/W) base fluid in a multipass crossflow minichannel heat exchanger. The time dependent thermal responses of the system in a laminar regime are predicted by solving the conservation equations using the finite volume method and SIMPLE algorithm. The transient regime is caused by a step change of nanofluid mass flow rate at the inlet of the minichannel heat exchanger. This step change can be analogous with a thermostat operation. In this study, three volume fractions up to 3 percent of Al2O3 nanoparticles dispersed to the base fluid EG/W are modeled and analyzed. In the numerical simulation, Al2O3-EG/W nanofluid is considered as a homogenous single-phase fluid. An analysis of the transient response for the variation of nanofluids volume concentrations is conducted.
2016-04-05
Journal Article
2016-01-0260
Yoshiichi Ozeki, Hideaki Nagano, Itsuhei Kohri
Abstract In order to develop various parts and components of electric vehicles, understanding the effects of their structures and thermal performance on the energy consumption and cruising distance is important. However, such essential and detailed information is generally not always available to suppliers of vehicle parts and components. This paper presents the development of a simple model of the energy consumption by an electric vehicle in order to roughly calculate the cruising performance based only on the published information to give to suppliers, who otherwise cannot obtain the necessary information. The method can calculate the cruising distance within an error of 4% compared to the published information. The effects of the glass and body heat transfer characteristics on the cruising performance in winter were considered as an example application of the proposed model.
Viewing 1 to 30 of 14893