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Viewing 1 to 30 of 4077
Technical Paper
2014-09-16
Andre Hessling
Reducing maintenance and improving safety for commercial aircraft can at times oppose each other. Advanced technologies in LED’s and Super-capacitors have the potential to reduce maintenance and improve safety for aircraft. By introducing LED’s and Super-capacitors the performance profiles of these technologies require a rethinking of the Lighting systems and equipment setups. Rewriting Lighting System requirements allow for greater design solutions which will provide better Lighting products to support operators which will in turn make them more profitable and improve safety over products that are flying today. Two examples are presented: an LED Landing Light and a Supercap based emergency light. 1) Aircrafts need adequate illumination for night time landing. Currently this requirement is met via high power halogen lamp or HID lights. Useful light for the pilot is a combination of intensity and direction. Too much light in undesired direction can cause excessive halation in adverse weather conditions forcing the pilots to shut down the lights entirely.
Technical Paper
2014-09-16
Matthieu Hutchison, Grégoire Lenoble, Umberto Badiali, Yannick Sommerer, Olivier Verseux, Eric Desmet
Fuel pressure surge is an essential topic for modern aircrafts and a main driver for airframe fuel system sizing. This phenomenon can occur both during normal and abnormal operations, notably resulting from a sudden change of fluid velocity due to the opening or closure of an engine valve. During aircraft development phase, Airbus specifies to engine manufacturers a pressure limit at the interface between the engine and airframe. The verification activities performed by engine manufacturers shall then ensure that the maximum pressure surge will not exceed these requirements. The purpose of this paper is to present the methodology developed by Airbus with the support of LMS Engineering (a Siemens PLM Software division) for the assessment of accurate fuel pressure surge at early program stages in the complete aircraft and engine environment. This methodology will help to avoid late airframe fuel system redesign and secure entry-into-service by driving the engine manufacturer verification & validation process.
Technical Paper
2014-09-16
Darcy Allison, Edward Alyanak
The design challenges associated with advanced supersonic aircraft are best handled with a multidisciplinary approach. These aircraft are highly coupled in that small changes to one subsystem can have far-reaching effects on others. For the class of aircraft called the efficient supersonic air vehicle (ESAV), particular attention must be paid to the propulsion system design as a whole including installation effects in the airframe design. The propulsion system assumed for the ESAV is a three-stream variable cycle engine. A computational model has been built with the Numerical Propulsion System Simulation (NPSS) software to analyze this engine. Along with the variable cycle NPSS model, a three-ramp external compression inlet model meant for conceptual design has been developed. This inlet model will be used to capture installation effects so that they are accounted for during the aircraft conceptual design. The NPSS and inlet models are parameterized so that they can be used in a multidisciplinary design optimization (MDO) process.
Technical Paper
2014-09-16
Rudolf Neydorf, Youriy Sigida
Identification of propeller traction power specifications in aircraft mathematical description problems Under the mathematical simulation of the aircraft dynamic motion, an identification problem for a number of constants and functions which cannot be analytically calculated appears. Dependences of aerodynamic gap coefficients of the aircraft body and the airflow, as well as the traction power specifications of the active propulsors used in flight by the aircraft, are related to such functions. Nowadays, propellers only are used in the airships and other aerial vessels with the aerostatic keeping in-flight principle. In the automatic flight control systems, they act as actuation devices. When constructing a mathematical aircraft model, the thrust developed by the propulsor is often taken for an input control. However, there are a great many phases of transforming forces, moments, and kinds of energy, between the real input control (customarily, it is introducing fuel or power supply to the servomotor input) and the rotor thrust load.
Technical Paper
2014-06-30
Barbara Neuhierl, David Schroeck, Sivapalan Senthooran, Philippe Moron
Abstract This paper presents an approach to numerically simulate greenhouse windnoise. The term “greenhouse windnoise” here describes the sound transferred to the interior through the glass panels of a series vehicle. Different panels, e.g. the windshield or sideglass, are contributing to the overall noise level. Attached parts as mirrors or wipers are affecting the flow around the vehicle and thus the pressure fluctuations which are acting as loads onto the panels. Especially the wiper influence and the effect of different wiper positions onto the windshield contribution is examined and set in context with the overall noise levels and other contributors. In addition, the effect of different flow yaw angles on the windnoise level in general and the wiper contributions in particular are demonstrated. As computational aeroacoustics requires accurate, highly resolved simulation of transient and compressible flow, a Lattice-Boltzmann approach is used. The noise transmission through the interior is then modeled by statistical energy analysis (SEA), representing the vehicle cabin and the panels excited by the flow.
Technical Paper
2014-06-30
Denis Blanchet, Anton Golota, Nicolas Zerbib, Lassen Mebarek
Abstract Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities in terms of i) how the convective and acoustic sources terms can be identified, ii) how the interaction between the source terms and the side glass can be described and finally iii) how the transfer path from the sources to the interior of the vehicle can be modelled. This paper discusses in detail these three aspects of wind noise simulation and recommends appropriate methods to deliver required results at the right time based on i) simulation and experimental data availability, ii) design stage and iii) time available to deliver these results. Several simulation methods are used to represent the physical phenomena involved such as CFD, FEM, BEM, FE/SEA Coupled and SEA. Furthermore, a 1D and 2D wavenumber transformation is used to extract key parameters such as the convective and the acoustic component of the turbulent flow from CFD and/or experimental data whenever available.
Technical Paper
2014-06-30
Gregor Tanner, David J. Chappell, Dominik Löchel, Niels Søndergaard
Abstract Modelling the vibro-acoustic properties of mechanical built-up structures is a challenging task, especially in the mid to high frequency regime, even with the computational resources available today. Standard modelling tools for complex vehicle parts include finite and boundary element methods (FEM and BEM), as well as Multi-Body Simulations (MBS). These methods are, however, robust only in the low frequency regime. In particular, FEM is not scalable to higher frequencies due to the prohibitive increase in model size. We have recently developed a new method called Discrete Flow Mapping (DFM), which extends existing high frequency methods, such as Statistical Energy Analysis or the so-called Dynamical Energy Analysis (DEA), to work on meshed structures. It provides for the first time detailed spatial information about the vibrational energy of a whole built-up structure of arbitrary complexity in this frequency range. The response of small-scale features and coupling coefficients between sub-components are obtained through local FEM models integrated in the global DFM treatment.
Technical Paper
2014-06-30
Ze Zhou, Jonathan Jacqmot, Gai Vo Thi, ChanHee Jeong, Kang-Duck Ih
Abstract The NVH study of trimmed vehicle body is essential in improving the passenger comfort and optimizing the vehicle weight. Efficient modal finite-element approaches are widely used in the automotive industry for investigating the frequency response of large vibro-acoustic systems involving a body structure coupled to an acoustic cavity. In order to accurately account for the localized and frequency-dependant damping mechanism of the trim components, a direct physical approach is however preferred. Thus, a hybrid modal-physical approach combines both efficiency and accuracy for large trimmed body analysis. Dynamic loads and exterior acoustic loads can then be applied on the trimmed body model in order to evaluate the transfer functions between these loads and the acoustic response in the car compartment. The scenario study of installing different trim components into the vehicle provides information on the acoustic absorption and dynamic damping with regard to added vehicle weight by the trim.
Technical Paper
2014-06-30
Arnaud Caillet, Antoine Guellec, Denis Blanchet, Thomas Roy
Abstract Since the last decade, the automotive industry has expressed the need to better understand how the different trim parts interact together in a complete car up to 400 Hz for structureborne excitations. Classical FE methods in which the acoustic trim is represented as non-structural masses (NSM) and high damping or surface absorbers on the acoustic cavity can only be used at lower frequencies and do not provide insights into the interactions of the acoustic trims with the structure and the acoustic volume. It was demonstrated in several papers that modelling the acoustic components using the poroelastic finite element method (PEM) can yield accurate vibro-acoustic response such as transmission loss of a car component [1,2,3]. The increase of performance of today's computers and the further optimization of commercial simulation codes allow computations on full vehicle level [4,5,6] with adequate accuracy and computation times, which is essential for a car OEM. This paper presents a study of a fully trimmed vehicle excited by structureborne excitations with almost all acoustic trims such as seats, dash insulator, instrument panel, headliner… which are modelled as poroelastic finite element (PEM) parts.
Technical Paper
2014-06-30
Rainer Stelzer, Theophane Courtois, Ki-Sang Chae, Daewon SEO, Seok-Gil Hong
Abstract The assessment of the Transmission Loss (TL) of vehicle components at Low-Mid Frequencies generally raises difficulties associated to the physical mechanisms of the noise transmission through the automotive panel. As far as testing is concerned, it is common in the automotive industry to perform double room TL measurements of component baffled cut-outs, while numerical methods are rather applied when prototype or hardware variants are not available. Indeed, in the context of recent efforts for reduction of vehicle prototypes, the use of simulation is constantly challenged to deliver reliable means of decision during virtual design phase. While the Transfer matrix method is commonly and conveniently used at Mid-High frequencies for the calculation of a trimmed panel, the simulation of energy transfer at low frequencies must take into account modal interactions between the vehicle component and the acoustic environment. After providing a brief review of the established approaches for TL simulation at LF, the article will present a new FE methodology for TL simulation and introduce the advantages of “in-situ” TL simulations by means of fluid-structure FE calculation.
Technical Paper
2014-05-07
Torbjörn Narström
Abstract The use of modern quenched and tempered steels in dumper bodies to reduce weight to increase the payload and reduce the fuel consumption is briefly discussed. Modern quenched and tempered steels in combination with adopted design concept will further increase weight savings of the dumper body. Use of these materials may lead to 4 times longer wear life than ordinary steels. One of the main load cases for a dumper body is impact of an object, i.e. boulders and rocks, into the body. A well-proven test setup is used to develop a model to predict failure and depth of the dent after the impact. A material model with damage mechanic was utilized to predict fracture. The developed model was used to study the effect of the geometry of the impacting object, thickness of the plate and unconstrained plate field. The model was also implemented in larger model and compared with a full scale test of dumper body. It was found that the most sensitive parameter is the geometry of the falling object.
Technical Paper
2014-05-07
Timo Björk, Ilkka Valkonen, Jukka Kömi, Hannu Indren
Abstract The development of weldable high-strength and wear-resistant steels have made modern structures such as booms and mobile equipment possible. These sorts of novel and effective designs could not be constructed with traditional mild steel. Unfortunately, the use of these novel steels requires proper design, and there is no practical design code for these novel steels. This paper addresses stability issues, which are important considerations for designs with high-strength steels, and the properties of the heat-affected zone, which may require special attention. Fatigue design is also discussed in this paper, and the importance of the weld quality is highlighted, along with discussions on which details in the weld are the most important. By comparing the test results with the classical load limit solution, it is determined that full plastic capacity is reached and that the samples display good strain properties. Additionally, the reliability of the classical formulas is shown by comparing them to a recently proposed, novel formula.
Technical Paper
2014-04-28
Kuldeepak Mahto, K.V. Balaji, A. Zainulabedin
Abstract The present paper discusses about a glossy polypropylene composition which can replace ABS and PC-ABS in the aesthetic interior and exterior bezels of a car with good stiffness and high flow. High Melt flow index of this composition minimizes the number of gate locations thereby drastically improving the aesthetics. Usage of Special Additives, and High Aspect ratio talc reduced the density of this composition as compared to a conventional PP compound. The combined benefits of lower weight, adequate stiffness, good gloss, scratch resistance and weathering resistance in the unpainted form makes this composition attractive for Interior and exterior aesthetic bezels. Again, this composition is cost-effective thereby reducing the part costs of interior and exterior bezels significantly.
Technical Paper
2014-04-28
Swapnil Pawar, Sandip Patil, Suhas Joshi, Rajkumar Singh
Abstract Tapping is an important process in assembly of aircraft structures because on an average one millions of tapped holes are made on an aircraft structure. However, sudden breakage of the tap is the most undesirable event frequently encountered during the tapping process. In particular, this can mostly occur when small diameter internal threads are made in a ‘difficult-to-cut’ material like titanium. For this reason, it has been a topic of industrial interest in the manufacturing sector for many years. The ultrasonic vibrations assisted tapping (UVAT) is a novel manufacturing technology, where ultrasonic vibrations are provided to the work piece in the axial direction. The present work is a comprehensive study involving experimental characterization. The experimentation shows that UVAT reduces the torque during tapping as compared to that of in conventional process. There is a 19.1% reduction in torque and about 20.3% reduction in cutting temperature in UVAT over that of in CT. The experimental analysis of UVAT process also shows that the superior surface and better machinability in UVAT over that of in CT.
Technical Paper
2014-04-01
Mehdi Safaei, Shahram Azadi, Arash Keshavarz, Meghdad Zahedi
Abstract The main end of this research is the optimization of engine sub-frame parameters in a passenger car to reduce the transmitted vibration to vehicle cabin through DOE method. First, the full vehicle model of passenger car including all its sub-systems such as engine, suspension and steering system is modeled in ADAMS/CAR and its accuracy is validated by exerting swept sine and step input. After that, the schematic geometry of sub-frame is modeled in CAD software and transferred to ADAMS/CAR. Hence, the efficiency of the sub-frame in terms of reducing the induced vibration to vehicle cabin is examined through the various road inputs e.g. swept sine, step and random road input type (B). The results will illustrate that the sub-frame has significant effect in reduction of transmitted vibration to occupants. In order to optimize the sub-frame parameters, the sensitivity analysis is performed to derive effective parameters of sub-frame using DOE method. In this regard, the parameters which have dominant effect on transmitted vibration (the stiffness of sub-frame bushing in vertical direction) are optimized via RSM (Response Surface Method) method.
Technical Paper
2014-04-01
Li Yan, Weikang Jiang, Jiangqi Zhou
Abstract Sound quality of vehicle interior noise affects passenger comfort. In order to improve the sound quality of a micro commercial vehicle, the vehicle interior noise under different conditions such as idle, constant speeds and accelerating is recorded by using artificial head with dual microphones. The sound quality of recorded noise is evaluated in both objective and subjective ways. Physical parameters of interior noise are calculated objectively, and annoyance score is analyzed subjectively using paired-comparison method. According to the regression analyzing of the annoyance score and the physical parameters, an objective evaluation parameter of the sound quality is employed. To analyze the vehicle body panel contribution to interior noise sound quality, the location and spectrum characteristics of major panel emission noise sources are identified based on partial singular valued decomposition (PSVD) method. By investigating the contribution of each noise sources to the sound quality evaluation formula, the dominant interior noise source is determined.
Technical Paper
2014-04-01
Yunkai Gao, Na Qiu, Jianguang Fang, Shanshan Wang
Abstract For achieving vehicle light weighting, the motion deviation is calculated for substitution of PMMA glazing for inorganic glass. In this paper, a test method is proposed to measure and calculate the motion deviation of the dual-curvature glass. To simulate the dual-curvature glass, the torus surface is fitted with least square method according to the window frame data, which are measured by Coordinate Measuring Machine. By using this method, the motion deviation of PMMA glazing and inorganic glass can be calculated, which can not only validate the effectiveness of motion simulation, but also compare the performances. The results demonstrate that the performance of PMMA glazing is better than that of inorganic glass and the simulation results is validated.
Technical Paper
2014-04-01
Horst Lanzerath, Niels Pasligh
Abstract Structural adhesives are widely used across the automotive industry for several reasons like scale-up of structural performance and enabling multi-material and lightweight designs. Development engineers know in general about the effects of adding adhesive to a spot-welded structure, but they want to quantify the benefit of adding adhesives on weight reduction or structural performance. A very efficient way is to do that by applying analytical tools. But, in most of the relevant non-linear load cases the classical lightweight theory can only help to get a basic understanding of the mechanics. For more complex load cases like full car crash simulations, the Finite Element Method (FEM) with explicit time integration is being applied to the vehicle development process. In order to understand the benefit of adding adhesives to a body structure upfront, new FEM simulation tools need to be established, which must be predictive and efficient. Therefore new FEM crash methods for structural adhesives have been investigated and validated with the help of test results.
Technical Paper
2014-04-01
Benoit Bidaine, Laurent Adam, Roger Assaker, Hanson Chang, Marc Duflot, Bender Kutub, Emmanuel Lacoste
Abstract In the steady quest for lightweighting solutions, continuous carbon fiber composites are becoming more approachable for design, now not only used in the aerospace but also the automotive industries. Carbon Fiber Reinforced Plastics (CFRP) are now being integrated into car body structures, used for their high stiffness and strength and low weight. The material properties of continuous carbon fiber composites are much more complex than metal, especially with respect to failure; this is further complicated by the fact that a single part is typically made from stacks of several unidirectional plies, each with a different fiber orientation. Hence failure occurs because of various mechanisms taking place at the ply level (matrix cracking, fiber breakage, fiber-matrix debonding) or between the plies (delamination). These mechanisms remain not fully understood and are investigated through experimental and virtual testing. To predict composite failure, we have developed advanced simulation strategies combining finite element analysis (FEA) and nonlinear micromechanical material modeling.
Technical Paper
2014-04-01
Shweta Rawat, Soumya Kanta Das
Abstract With the ever increasing emphasis on vehicle occupant safety, the safety of pedestrians is getting obscured behind the A-pillars that are expanding in order to meet the federal roof crush standards. The serious issue of pillar blind spots poses threats to the pedestrians who easily disappear from driver's field of view. To recognize this blinding danger and design the car around the driver's eye, this paper proposes the implementation of Aluminum Oxynitride marked under name AlON by Surmet Corporation for fabrication of A-pillars that can allow more than 80% visibility through them. AlON is a polycrystalline ceramic with cubic spinel crystal structure and is composed of aluminum, oxygen and nitrogen. With hardness more than 85% than sapphire, its applications range from aerospace to defense purposes which qualify it in terms of strength and thus imply that it can be conveniently used as A-pillars in vehicles. Furthermore, it possesses characteristics of being bonded to metals as well.
Technical Paper
2014-04-01
Pankaj K. Mallick, Rajesh Boorle
Abstract Sandwich panels with high modulus/high strength skin material and low density/low modulus core material have higher stiffness-to-weight ratio than monolithic panels. In this paper, sandwich panels with corrugated core are explored as a lightweighting concept for improved stiffness. The skin and the core materials are a high strength steel, aluminum alloy or carbon fiber-epoxy composite. The core has a triangular corrugation, a trapezoidal corrugation and a rectangular corrugation. The stiffness of the sandwich panels is analytically determined and compared with monolithic panels of equal mass. It is shown that the stiffness of the sandwich panels is 5 to 7 times higher than that of the monolithic panels.
Technical Paper
2014-04-01
Suhas Kangde, Vishal Shitole, Ashish Kumar Sahu
Abstract Automotive Suspension is one of the critical system in load transfer from road to Chassis or BIW. Using flex bodies in Multi body simulations helps to extract dynamic strain variation. This paper highlights how the MBD and FE integration helped for accurate strain prediction on suspension components. Overall method was validated through testing. Good strain correlation was observed in dynamic strains of constant amplitude in different loading conditions. Combination of different direction loading was also tested and correlated. Method developed can be used in the initial phase of the vehicle development program for suspension strength evaluation. Suspension is one of the important system in vehicle which is subjected to very high loading in all the directions. To predict the dynamic stresses coming on the suspension system due to transient loads, faster and accurate method is required. To accelerate the suspension design process it become necessary to get good accuracy in the results.
Technical Paper
2014-04-01
Qiang Yi, Stanley Chien, David Good, Yaobin Chen, Rini Sherony
Abstract According to pedestrian crash data from 2010-2011 the U.S. General Estimates System (GES) and the Fatality Analysis Report System (FARS), more than 39% of pedestrian crash cases occurred at night and poor lighting conditions. The percentage of pedestrian fatalities in night conditions is over 77%. Therefore, evaluating the performance of pedestrian pre-collision systems (PCS) at night is an essential part of the pedestrian PCS performance evaluation. The Transportation Active Safety Institute (TASI) of Indiana University-Purdue University Indianapolis (IUPUI) is conducting research for the establishment of PCS test scenarios and procedures in collaboration with Toyota's Collaborative Safety Research Center. The objective of this paper is to describe the design and implementation of a reconfigurable road lighting system to support the pedestrian PCS performance evaluation for night road lighting conditions. First, the test conditions of the road lighting (light intensity and uniformity) are generated by combining recommendations from road lighting design standards and the average measured lighting levels at various crash locations.
Technical Paper
2014-04-01
Gaurav Gupta, Rituraj Gautam, Chetan Prakash Jain
Abstract Interior sound quality is one of the significant factors contributing to the comfort level of the occupants of a passenger car. One of the major reasons for the deterioration of interior sound quality is the booming noise. Booming noise is a low frequency (20Hz∼300Hz) structure borne noise which occurs mainly due to the powertrain excitations or road excitations. Several methods have been developed over time to identify and troubleshoot the causes of booming noise [1]. In this paper an attempt has been made to understand the booming noise by analyzing structural (panels) and acoustic (cavity) modes. Both the structural modes and the acoustic modes of the vehicle cabin were measured experimentally on a B-segment hatchback vehicle using a novel approach and the coupled modes were identified. Panels contributing to booming noise were identified and countermeasures were taken to modify these panels to achieve decoupling of structural and cavity modes which results in the reduction of cabin noise levels.
Technical Paper
2014-04-01
Keisuke Kojima, Takeshi Ogawa
Abstract The CO2 emission from automobile plants is large. A majority of this quantity comes from the body painting process. A breakdown of CO2 emissions from the painting process shows the significant impact of painting process equipment such as the oven used to cure paint and the air conditioning facilities used to maintain controlled temperature and humidity on CO2 emissions. It was concluded, therefore, that shortening these processes will effectively promote the reduction of CO2 emissions. Removing the primer process means that the basecoat (BC) and clearcoat (CC), which provide color and marketability, would be applied on the E-coat directly. By the removing the primer several issues are raised such as stone chipping resistance, weather durability, color variation and appearance. By contrast, this 3Wet painting system applies two coats of waterborne basecoat, dividing it up into 1-Base and 2-Base and then CC, in order to achieve both targets, quality and color variation. For severe corrosion areas, chipping primer (CP) is applied to keep chipping resistance before the application of 1-Base.
Technical Paper
2014-04-01
Katsuyoshi Kaneko, Toshikazu Hirobe, Yusuke Kawada, Tatsumasa Hidaka
Abstract By increasing the percentage of highly dissociative strong acid components included in the neutralizing acid of the electrodeposition coating, it was possible to improve electrical conductivity and coulomb efficiency and achieve excellent throwing power. The GA cratering caused by the increase in the strong acid ratio was resolved by setting the strong acid ratio to 90% while reducing MEQ. By increasing coulomb efficiency, the quantity of hydrogen gas produced during electrodeposition was minimized, and as a result, gas pinholes remaining in the coating were reduced, increasing the smoothness of the coating beyond than that of the current materials. As a result of this study, the usage of e-coating per vehicle body was reduced by approximately 11%.
Technical Paper
2014-04-01
Luciano Lukacs, Mahendra Dassanayake, Iuri Pepe
Abstract Nighttime driving behavior differs from that during the day because of unique scenarios presented in a driver's field of vision. At night drivers have to rely on their vehicle headlamps to illuminate the road to be able to see the environment and road conditions in front of him. In recent decades car illumination systems have undergone considerable technological advances such as the use of a Light Emitting Diode (LED) in Adaptive Front-lighting Systems (AFS), a breakthrough in lighting technology. This is rapidly becoming one of the most important innovative technologies around the world within the lighting community. This paper discusses driver's needs given the environment and road conditions using a survey applied to compare the needs of both truck and car drivers under different road conditions. The results show the potential and suitability of the methodology proposed for controlling truck-related lighting in any emergent market.
Technical Paper
2014-04-01
Rainer Neumann
Abstract Since 2012, adaptive driving beam (ADB) was homologated first in the ECE world (ECE 123). The idea behind is a camera based lighting system, which enables the driver to achieve at night nearly high beam visibility without glaring oncoming or proceeding vehicles and road users. Once the presence of other vehicles is detected the headlamps change the light pattern and block the light where the oncoming or proceeding vehicles are located. Light sources are typically High Intensity Discharge (HID) bulbs, but today also first LED applications are visible. For SAE, the definition of the parameters and the requested regulation changes to allow such systems are in progress. The paper reports about an extensive study executed in Germany at TU Darmstadt to investigate not only the improvement in visibility for the driver with such systems, but also evaluate the disability and discomfort glare for other road users. The results are demonstrating clearly, that the existing ADB systems do not cause additional glare for the road users and also do not lead to an increased subjective discomfort glare rating.
Technical Paper
2014-04-01
Madhav Khadilkar
Abstract The purpose of Federal Motor Vehicle Safety Standard 216 is to reduce fatalities and serious injuries when vehicle roof crushes into occupant compartment during rollover crash. Upgraded roof crush resistance standard (571.216a Standard No. 216a) requires vehicle to achieve maximum applied force of 3.0 times unloaded vehicle weight (UVW) on both driver and passenger sides of the roof. (For vehicles with gross vehicle weight rating ≤ 6,000 lb.) This paper provides an overview of current approach for dual side roof strength Finite Element Analysis (FEA) and its limitations. It also proposes a new approach based on powerful features available in virtual tools. In the current approach, passenger side loading follows driver side loading and requires two separate analyses before arriving at final assessment. In the proposed approach only one analysis suffices as driver and passenger side loadings are combined in a single analysis. This is achieved by using sensors to control loadings, resulting in reduced consumption of CPU time (for computer simulation) and disk space utilization without compromising accuracy of current approach.
Technical Paper
2014-04-01
Vesna Savic, Matthew Pawlicki, Paul Krajewski, Mark Voss, Louis Hector, Keith Snavely
Abstract Global regulations intended to enhance pedestrian protection in a vehicle collision, thereby reducing the severity of pedestrian injuries, are presenting significant challenges to vehicle designers. Vehicle hoods, for example, must absorb a significant amount of energy over a small area while precluding impact with a hard engine compartment component. In this paper, a simple passive approach for pedestrian protection is introduced in which thin metal alloy sheets are bent to follow a C-shaped cross-sectional profile thereby giving them energy absorbing capacity during impact when affixed to the underside of a hood. Materials considered were aluminum (6111-T4, 5182-O) and magnesium (AZ31-O, AZ61-O, ZEK100) alloys. To evaluate the material effect on the head injury criterion (HIC) score without a hood, each C-channel absorber was crushed in a drop tower test using a small dart. Two high speed cameras captured dart image data before and during impact from which HIC scores were computed with stereo digital image correlation (DIC).
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