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Viewing 1 to 30 of 318
2015-04-14
Technical Paper
2015-01-0537
Hong Tae Kang, Abolhassan Khosrovaneh, Xuming Su, Yung-Li Lee, Mingchao Guo, Chonghua Jiang, Zhen Li
Magnesium alloys have low weldability, thus self-piercing rivet (SPR) joint is one of options for joining them. This research investigates the fatigue performance of SPR for magnesium alloys including AZ31, AM30, and AM60. Lap-shear and coach peel specimens for these alloys are fabricated and tested for understanding fatigue performance of the joint. Structural stress – life (S-N) curves are developed with the test results. This approach is validated with simple structural specimens that include three or two joints in each specimen. It is also intensively studied to identify the proper representation of the joint in finite element models.
2015-04-14
Technical Paper
2015-01-0541
Zhigang Wei, Pingsha Dong
Mean stress effects in stress-life and strain-life fatigue have been systematically investigated for several materials such as steels, aluminum alloys and titanium alloys under uniaxial fatigue loading. Several engineering models or equations, such as Goodman, Morrow, Smith-Water-Topper and Walker, have been thoroughly examined, and it was found that the Walker equation with an adjustable fitting parameter gives the best results. Actually, these two-parameter (range and mean or maximum) driving force methods have been intensely studied in terms of both stress-life/strain-life fatigue and fatigue crack growth. It is generally agreed that the Walker-type relationship is the most appropriate model to describe the two-driving force fatigue with the Walker exponent reflecting the sensitivity of materials to mean stress.
2015-04-14
Technical Paper
2015-01-0202
Armin Wasicek, Andre Weimerskirch
Combatting the modification of automotive control systems is a current and future challenge for OEMs and suppliers. ‘Chip-tuning’ is a manifestation of manipulation of a vehicle’s original setup and calibration. With the increase in automotive functions implemented in software and corresponding business models, chip-tuning will become a major concern. Recognizing tuned control units in a vehicle is required to report that circumstance for technical as well as legal reasons. This work approaches the problem by capturing the behavior of relevant control units within a machine learning system called a recognition module. The recognition module continuously monitors vehicle’s sensor data. It comprises a set of classifiers that have been trained on the intended behavior of a control unit before the vehicle is delivered. When the vehicle is on the road, the recognition module uses the classifier together with current data to ascertain that the behavior of the vehicle is as intended.
2015-04-14
Technical Paper
2015-01-0466
Boxiao Chen, Yan Fu, Margaret Strumolo, Xiuli Chao, Michael Tamor
Greenhouse gas emission targets are becoming more stringent for both automakers and electricity generators. With the introduction of plug-in hybrid and electric vehicles, the light duty vehicle (LDV) and electricity generation sectors become connected. This provides an opportunity for both sectors to work together to achieve the cost efficient reduction of CO2 emission. In addition, the abundant natural gas in USA is drawing increased attention from both policy makers and various industries recently due to its low cost and low carbon content. NG has the potential to ease the pressure from CO2 emission constraints for both the LDV and the electricity generation sectors while simultaneously reducing their fuel costs. An analytical model is developed to evaluate the total societal costs and CO2 emissions for both sectors. The model includes electric vehicles, as well as conventional, hybrid and plug-in hybrid vehicles that can be fueled by either gasoline or NG.
2015-04-14
Technical Paper
2015-01-0602
Shin-Jang Sung, Jwo Pan, Mohammed Yusuf Ali, Jagadish Sorab, Cagri Sever
In this paper, the evolution equation for the active yield surface during the unloading/reloading process based on the pressure-sensitive Drucker–Prager yield function and a recently developed anisotropic hardening rule with a non-associated flow rule is first presented. A user material subroutine based on the anisotropic hardening rule and the constitutive relation was written and implemented into the commercial finite element program ABAQUS. A two-dimensional plane strain finite element analysis of a crankshaft section under fillet rolling was conducted. After the release of the roller, the magnitude of the compressive residual hoop stress for the material with consideration of pressure sensitivity typically for cast irons is smaller than that without consideration of pressure sensitivity. In addition, the magnitude of the compressive residual hoop stress for the pressure-sensitive material with the non-associated flow rule is smaller than that with the associated flow rule.
2015-04-14
Technical Paper
2015-01-0708
Catherine M. Amodeo, Jwo Pan
In this paper, mode I and mode II stress intensity factor solutions for gas metal arc welds in single lap-shear specimens are investigated by the analytical stress intensity factor solutions and by finite element analyses. Finite element analyses were carried out in order to obtain the computational stress intensity factor solutions for both realistic and idealized weld geometries. The computational results indicate that the stress intensity factor solutions for the realistic welds are lower than the analytical solutions for the idealized weld geometry. The computational results can be used for the estimation of fatigue lives in a fatigue crack growth model under mixed mode loading conditions for gas metal arc welds.
2015-04-14
Technical Paper
2015-01-0861
Matthew Younkins, Margaret S. Wooldridge, Brad A. Boyer
Hydrogen fueled internal combustion engines have potential for high thermal efficiencies; however, high efficiency conditions can produce high nitrogen oxide emissions (NOx) that are challenging to treat using conventional 3-way catalysts. This work presents the results of an experimental study to reduce NOx emissions while retaining high thermal efficiencies in a single-cylinder research engine fueled with hydrogen. Specifically, the effects on engine performance of the injection of water into the intake air charge were explored. The hydrogen fuel was injected into the cylinder directly. Several parameters were varied during the study, including the amount of water injected into the intake charge, the amount of fuel injected, the phasing of the fuel injection, the number of fuel injection events, and the ignition timing. The results were compared with expectations for a conventionally operated hydrogen engine where load was controlled through changes in equivalence ratio.
2015-04-14
Technical Paper
2015-01-1080
Eduardo J. Barrientos, Matti M. Maricq, Andre L. Boehman, James E. Anderson
Biodiesel has been proven to have a strong impact on the oxidative reactivity of diesel soot. The fatty acid methyl esters, of which biodiesel is comprised, exhibit a more complex ignition chemistry than normal alkanes of equivalent carbon number. Studies have shown a clear dependence of soot reactivity on fuel oxygenate molecular structure, suggesting that the unique oxidation behavior of esters may be a governing factor of the enhanced soot oxidation behavior presented by biodiesel. A study and analysis of the relation of biodiesel chemical structures to the resulting soot characteristics and soot oxidative reactivity was conducted. Soot samples generated from the combustion of various methyl esters, alkanes, biodiesel and diesel fuels in laminar co-flow diffusion flames were analyzed to evaluate the impact of fuel-bound oxygen in fatty acid esters on soot oxidation behavior.
2015-04-14
Technical Paper
2015-01-1452
Kathleen DeSantis Klinich, Kyle Boyle, Laura Malik, Miriam Manary, Jingwen Hu
This study documented the position and orientation of child restraint systems (CRS) installed in the second rows of vehicles, providing a database of 486 installations. Thirty-one different CRS were evaluated, selected to provide a range of manufacturers, sizes, types, and weight limits. Eleven CRS were rear-facing only, fourteen were convertibles, five were combination restraints, and one was a booster. Ten top-selling vehicles were selected to provide a range of manufacturers and body styles: four sedans, four SUVS, one minivan, and one wagon. Each CRS was marked with three reference points on each moving component. The contours and landmarks of each CRS were first measured in the laboratory. Vehicle interior contours, belt anchors, and LATCH anchors were measured using a similar process. Then each CRS was installed in a vehicle using LATCH according to manufacturers’ directions, and the reference points of each CRS component were measured to document the installed orientation.
2015-04-14
Technical Paper
2015-01-0291
Radovan Miucic, Samer Rajab, Sue Bai, James Sayer, Dillon Funkhouser
Many Intelligent Transportation System (ITS) technologies have been developed to improve the safety and efficiency of cars, trucks, public transport and infrastructure. However, very few ITS have been developed specifically for motorcycle user protection. In this paper an overview of vehicle-to-motorcycle wireless communication systems research status in US, EU and Japan is provided. The system enables vehicles and motorcycles to exchange safety information such as speed, heading, location, brake status through 5.9 GHz Dedicated Short Range Communication (DSRC) protocol. The vehicles and motorcycles can then assess the potential threat level based on the incoming messages from the nearby traffic. Several high-impact motorcycle-to-vehicle collision scenarios are analyzed.
2015-04-14
Technical Paper
2015-01-1754
Wei-Jen Lai, Jwo Pan
The analytical stress intensity factor and J integral solutions for welds in lap-shear specimens of two dissimilar sheets are presented in the normalized forms. The analytical solutions were selectively validated by two-dimensional finite element analyses. The interface crack parameters, the stress intensity factor solutions, and the J integral solutions for welds in lap-shear specimens of different combinations of steel, aluminum, and magnesium, and the combination of aluminum and copper sheets of different thickness ratios are then presented for convenient fracture and fatigue analyses. The transition thickness ratios for critical crack locations for different combinations of dissimilar materials are then determined from the analytical solutions. The transition weld widths for applicable ranges of the weld widths for the analytical solutions based on the beam bending theory are also presented.
2015-04-14
Technical Paper
2015-01-1710
Xinran Tao, Kan Zhou, Andrej Ivanco, John R. Wagner, Heath Hofmann, Zoran Filipi
ABSTRACT The components in a hybrid electric vehicle (HEV) powertrain include the battery pack, an internal combustion engine, and the electric machines such as motors and possibly a generator. These components generate a considerable amount of heat during driving cycles. A robust thermal management system with advanced controller, designed for temperature tracking, is required for vehicle safety and energy efficiency. This paper examines the integration of an advanced control algorithm to a HEV powertrain cooling system featuring an electric-mechanical compressor, coolant pump, three radiators, and heat exchanger and radiator fans. Mathematical models are developed to numerically describe the thermal behavior of these powertrain elements. A series of controllers are designed to effectively manage the battery pack, electric motors, and the internal combustion engine temperatures.
2014-04-01
Technical Paper
2014-01-1801
Andrej Ivanco, Kan Zhou, Heath Hofmann, Zoran Filipi
Abstract The fidelity of the hybrid electric vehicle simulation is increased with the integration of a computationally-efficient finite-element based electric machine model, in order to address optimization of component design for system level goals. In-wheel electric motors are considered because of the off-road military application which differs significantly from commercial HEV applications. Optimization framework is setup by coupling the vehicle simulation to the constrained optimization solver. Utilizing the increased design flexibility afforded by the model, the solver is able to reshape the electric machine's efficiency map to better match the vehicle operation points. As the result, the favorable design of the e-machine is selected to improve vehicle fuel economy and reduce cost, while satisfying performance constraints.
2014-04-01
Technical Paper
2014-01-0808
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.
2014-04-01
Technical Paper
2014-01-0984
Aledoni Keci, Nia R. Harrison, S. George Luckey
Abstract The aluminum alloy 7075-T6 has the potential to be used for structural automotive body components as an alternative to boron steel. Although this alloy shows poor formability at room temperature, it has been demonstrated that hot stamping is a feasible sheet metal process that can be used to overcome the forming issues. Hot stamping is an elevated temperature forming operation in which a hot blank is formed and quenched within a stamping die. Attaining a high quench rate is a critical step of the hot stamping process and corresponds to maximum strength and corrosion resistance. This work looks at measuring the quench rate of AA7075-T6 by way of three different approaches: water, a water-cooled plate, and a bead die. The water-cooled plate and the bead die are laboratory-scale experimental setups designed to replicate the hot stamping/die quenching process.
2014-04-01
Technical Paper
2014-01-1276
Benjamin Lawler, Joshua Lacey, Nicolas Dronniou, Jeremie Dernotte, John E. Dec, Orgun Guralp, Paul Najt, Zoran Filipi
Abstract Refinements were made to a post-processing technique, termed the Thermal Stratification Analysis (TSA), that couples the mass fraction burned data to ignition timing predictions from the autoignition integral to calculate an apparent temperature distribution from an experimental HCCI data point. Specifically, the analysis is expanded to include all of the mass in the cylinder by fitting the unburned mass with an exponential function, characteristic of the wall-affected region. The analysis-derived temperature distributions are then validated in two ways. First, the output data from CFD simulations are processed with the Thermal Stratification Analysis and the calculated temperature distributions are compared to the known CFD distributions.
2014-04-01
Technical Paper
2014-01-0488
Peter Kempf
Abstract Discuss the basics of posturing and positioning of the full range of occupants necessary to cover the required anthropometric demographics in combat vehicles, both ground and air, since there are similarities to both and that they are both very different than the traditional automotive packaging scenarios. It is based on the Eye Reference Point and the Design Eye Point. Discuss the three Reach Zones: Primary, Secondary and Tertiary. Discuss Vision Zones and potentially ground intercepts. Discuss body clearances, both static and dynamic. Discuss the basic effects of packaging occupants with body armor with respect to SRP's and MSRP's.
2014-04-01
Technical Paper
2014-01-0445
Flaura Winston, Catherine McDonald, Venk Kandadai, Zachary Winston, Thomas Seacrist
Abstract Driving simulators offer a safe alternative to on-road driving for the evaluation of performance. In addition, simulated drives allow for controlled manipulations of traffic situations producing a more consistent and objective assessment experience and outcome measure of crash risk. Yet, few simulator protocols have been validated for their ability to assess driving performance under conditions that result in actual collisions. This paper presents results from a new Simulated Driving Assessment (SDA), a 35- to-40-minute simulated assessment delivered on a Real-Time® simulator. The SDA was developed to represent typical scenarios in which teens crash, based on analyses from the National Motor Vehicle Crash Causation Survey (NMVCCS). A new metric, failure to brake, was calculated for the 7 potential rear-end scenarios included in the SDA and examined according two constructs: experience and skill.
2014-04-01
Technical Paper
2014-01-0674
Byungchan Lee, Dohoy Jung, John Myers, Jae-Hoon Kang, Young-Ho Jung, Kwang-Yeon Kim
Abstract A numerical study is conducted to investigate the effect of changing engine oil and automatic transmission fluid (ATF) temperatures on the fuel economy during warm-up period. The study also evaluates several fuel economy improving devices that reduce the warm-up period by utilizing recycled exhaust heat or an electric heater. A computer simulation model has been developed using a multi-domain 1-D commercial software and calibrated using test data from a passenger vehicle equipped with a 2.4 / 4-cylinder engine and a 6-speed automatic transmission. The model consists of sub-models for driver, vehicle, engine, automatic transmission, cooling system, engine oil circuit, ATF circuit, and electrical system. The model has demonstrated sufficient sensitivity to the changing engine oil and ATF temperatures during the cold start portion of the Federal Test Procedure (FTP) driving cycle that is used for the fuel economy evaluation.
2014-04-01
Technical Paper
2014-01-1586
John Hoard, Nandagopalan Venkataramanan, Barbara Marshik, William Murphy
Abstract Ammonia, often present in exhaust gas samples, is a polar molecule gas that interacts with walls of the gas sampling and analysis equipment resulting in delayed instrument response. A set of experiments quantified various materials and process parameters of a heated sample line system for ammonia (NH3) response using a Fourier Transform infrared spectrometer (FTIR). Response attenuation rates are due to mixing and diffusion during transport as well as NH3 wall storage. Mixing/diffusion effects cause attenuation with a time constant 1-10 seconds. Wall storage attenuation has a time constant 10-200 seconds. The effects of sample line diameter and length, line temperature, line material, hydrated versus dry gas, and flow rate were examined. All of these factors are statistically significant to variation of at least one of the time constants. The NH3 storage on the sample system walls was calculated as a function of the experimental test as well.
2014-04-01
Journal Article
2014-01-0463
Clive D'Souza
The purpose of this paper is to demonstrate the impact of low- floor bus seating configuration, passenger load factor (PLF) and passenger characteristics on individual boarding and disembarking (B-D) times -a key component of vehicle dwell time and overall transit system performance. A laboratory study was conducted using a static full-scale mock-up of a low-floor bus. Users of wheeled mobility devices (n=48) and walking aids (n=22), and visually impaired (n=17) and able-bodied (n=17) users evaluated three bus layout configurations at two PLF levels yielding information on B-D performance. Statistical regression models of B-D times helped quantify relative contributions of layout, PLF, and user characteristics viz., impairment type, power grip strength, and speed of ambulation or wheelchair propulsion. Wheeled mobility device users, and individuals with lower grip strength and slower speed were impacted greater by vehicle design resulting in increased dwell time.
2014-04-01
Journal Article
2014-01-0111
Narayanan Kidambi, R. L. Harne, Yuji Fujii, Gregory M. Pietron, K. W. Wang
Dynamic vehicle loads play critical roles for automotive controls including battery management, transmission shift scheduling, distance-to-empty predictions, and various active safety systems. Accurate real-time estimation of vehicle loads such as those due to vehicle mass and road grade can thus improve safety, efficiency, and performance. While several estimation methods have been proposed in literature, none have seen widespread adoption in current vehicle technologies despite their potential to significantly improve automotive controls. To understand and bridge the gap between research development and wider adoption of real-time load estimation, this paper assesses the accuracy and performance of four estimation methods that predict vehicle mass and/or road grade.
2014-04-01
Journal Article
2014-01-0735
Zhimin Xi, Pan Hao, Yan Fu, Ren-Jye Yang
Available methodologies for model bias identification are mainly regression-based approaches, such as Gaussian process, Bayesian inference-based models and so on. Accuracy and efficiency of these methodologies may degrade for characterizing the model bias when more system inputs are considered in the prediction model due to the curse of dimensionality for regression-based approaches. This paper proposes a copula-based approach for model bias identification without suffering the curse of dimensionality. The main idea is to build general statistical relationships between the model bias and the model prediction including all system inputs using copulas so that possible model bias distributions can be effectively identified at any new design configurations of the system. Two engineering case studies whose dimensionalities range from medium to high will be employed to demonstrate the effectiveness of the copula-based approach.
2014-04-01
Journal Article
2014-01-0784
Catherine Amodeo, Jwo Pan
The failure modes of gas metal arc welds in notched lap-shear specimens of high strength low alloy (HSLA) steel are investigated. Notched lap-shear specimens of gas metal arc welds were first made. Quasi-static test results of the notched lap-shear specimens showed two failure locations for the welds. The specimens cut from coupons with shorter weld lengths failed near the weld root whereas the specimens cut from coupons with longer weld lengths failed near the weld toe. Micro-hardness tests were conducted in order to provide an assessment of the mechanical properties of the base metal, the heat affected zone, and the weld metal. In order to understand the failure modes of these welds, finite element models were developed with the geometric characteristics of the weld metals and heat affected zones designed to match those of the micrographs of the cross sections for the long and short welds.
2014-04-01
Journal Article
2014-01-0444
Yinghao Huang, Wenduo Wang, Chen Fang, Yi Murphey, Dev S. Kochhar
A transportable instrumentation package to collect driver, vehicle and environmental data is described. This system is an improvement on an earlier system and is called TIP-II [13]. Two new modules were designed and added to the original system: a new and improved physiological signal module (PH-M) replaced the original physiological signals module in TIP, and a new hand pressure on steering wheel module (HP-M) was added. This paper reports on exploratory tests with TIP-II. Driving data were collected from ten driver participants. Correlations between On-Board-Diagnostics (OBD), video data, physiological data and specific driver behavior such as lane departure and car following were investigated. Initial analysis suggested that hand pressure, skin conductance level, and respiration rate were key indicators of lane departure lateral displacement and velocity, immediately preceding lane departure; heart rate and inter-beat interval were affected during lane changes.
2014-04-01
Journal Article
2014-01-1985
Michael Flannagan, Mitsuhiro Uchida, John Michael Sullivan, Mary Lynn Buonarosa
This study was designed to investigate how the spectral power distribution (SPD) of LED headlamps (including correlated color temperature, CCT) affects both objective driving performance and subjective responses of drivers. The results of this study are not intended to be the only considerations used in choosing SPD, but rather to be used along with results on how SPD affects other considerations, including visibility and glare. Twenty-five subjects each drove 5 different headlamps on each of 5 experimental vehicles. Subjects included both males and females, in older (64 to 85) and younger (20 to 32) groups. The 5 headlamps included current tungsten-halogen (TH) and high-intensity discharge (HID) lamps, along with three experimental LED lamps, with CCTs of approximately 4500, 5500, and 6500 K. Driving was done at night on public roads, over a 21.5-km route that was selected to include a variety of road types.
2013-12-26
Article
Algorithms rein in redundant motor-in-wheel drives to keep lightweight EVs safe and stable.
2013-12-19
Article
The goal of the program, which began in 2007, is to advance development of new sensor and control technologies with the aim of applying them to the active safety systems of future vehicles.
2013-09-24
Technical Paper
2013-01-2357
Zhigang Wei, Jason Hamilton, Fulun Yang, Limin Luo, Shengbin Lin, HongTae Kang, Pingsha Dong
Great efforts have been made to develop the ability to accurately and quickly predict the durability and reliability of vehicles in the early development stage, especially for welded joints, which are usually the weakest locations in a vehicle system. A reliable and validated life assessment method is needed to accurately predict how and where a welded part fails, while iterative testing is expensive and time consuming. Recently, structural stress methods based on nodal force/moment are becoming widely accepted in fatigue life assessment of welded structures. There are several variants of structural stress approaches available and two of the most popular methods being used in automotive industry are the Volvo method and the Verity method. Both methods are available in commercial software and some concepts and procedures related the nodal force/moment have already been included in several engineering codes.
2013-06-17
Article
The most exciting opportunities are those emerging around V2X technologies, such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. For now, that does not include V2G, the vehicle-to-grid approach promoted by many plug-in advocates.
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