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Technical Paper

A Computational Approach for Evaluating the Acoustic Detection of a Military Vehicle

ADRPM (Acoustic Detection Range Prediction Model) is a software program that models the propagation of acoustic energy through the atmosphere and evaluates detectable distance. ADRPM predicts the distance of detection for a noise source based on the acoustic signature of the source. The acoustic signature of a vehicle is computed by combining BEA and EBEA computations with nearfield measurements. The computed signature is utilized as the input to ADRPM. Once the initial detection range is predicted the main contributors to the acoustic detection are identified by ADRPM and their location on the vehicle is modified in order to assess the corresponding effect to the detectable distance of the vehicle.
Technical Paper

A Fatigue Crack Growth Model for Spot Welds in Square-Cup and Lap-Shear Specimens under Cyclic Loading Conditions

A fatigue crack growth model is adopted in this paper to investigate the fatigue lives of resistance spot welds in square-cup and lap-shear specimens of dual phase, low carbon and high strength steels under cyclic loading conditions. The fatigue crack growth model is based on the global stress intensity factor solutions for main cracks, the local stress intensity factor solutions for kinked cracks as functions of the kink length, the experimentally determined kink angles, and the Paris law for kinked crack propagation. The predicted fatigue lives based on the fatigue crack growth model are then compared with the experimental data. The results indicate that the fatigue life predictions based on the fatigue crack growth model are in agreement with or lower than the experimental results.
Technical Paper

A Field Study of Distance Perception with Large-Radius Convex Rearview Mirrors

One of the primary reasons that FMVSS 111 currently requires flat rearview mirrors as original equipment on the driver's side of passenger cars is a concern that convex mirrors might reduce safety by causing drivers to overestimate the distances to following vehicles. Several previous studies of the effects of convex rearview mirrors have indicated that they do cause overestimations of distance, but of much lower magnitude than would be expected based on the mirrors' levels of image minification and the resulting visual angles experienced by drivers. Previous studies have investigated mirrors with radiuses of curvature up to 2000 mm. The present empirical study was designed to investigate the effects of mirrors with larger radiuses (up to 8900 mm). Such results are of interest because of the possible use of large radiuses in some aspheric mirror designs, and because of the information they provide about the basic mechanisms by which convex mirrors affect distance perception.
Technical Paper

A General Failure Criterion for Spot Welds with Consideration of Plastic Anisotropy and Separation Speed

A general failure criterion for spot welds is proposed with consideration of the plastic anisotropy and the separation speed for crash applications. A lower bound limit load analysis is conducted to account for the failure loads of spot welds under combinations of three forces and three moments. Based on the limit load solution and the experimental results, an engineering failure criterion is proposed with correction factors determined by different spot weld tests. The engineering failure criterion can be used to characterize the failure loads of spot welds with consideration of the effects of the plastic anisotropy, separation speed, sheet thickness, nugget radius and combinations of loads. Spot weld failure loads under uniaxial and biaxial opening loads and those under combined shear and twisting loads from experiments are shown to be characterized well by the engineering failure criterion.
Technical Paper

A Generic Methodology for Chamber Flame Geometry Modeling

Combustion flame geometry calculation is a critical task in the design and analysis of combustion engine chamber. Combustion flame directly influences the fuel economy, engine performance and efficiency. Currently, many of the flame geometry calculation methods assume certain specific chamber and piston top shapes and make some approximations to them. Even further, most methods can not handle multiple spark plug set-ups. Consequently, most of the current flame geometry calculation methods do not give accurate results and have some built-in limitations. They are particularly poor for adapting to any kind of new chamber geometry and spark plug set-up design. This report presents a novel methodology which allows the accurate calculation of flame geometry regardless of the chamber geometry and the number of spark plugs. In this methodology, solid models are used to represent the components within the chamber and unique attributes (colors) are attached respectively to these components.
Technical Paper

A Hybrid Finite Element Formulation for Analyzing Systems of Beams and Plates in the Mid-Frequency Range

A hybrid Finite Element Analysis (hybrid FEA) formulation has been developed in the past for computing the mid-frequency vibration of systems that contain one type of energy. The hybrid FEA is based on characterizing as long members in a system all the members that contain a large number of wavelengths within their dimension. All the remaining members are considered as short. The Energy Finite Element Analysis (EFEA) is employed for modeling the behavior of the long members, while the conventional FEA method is utilized for modeling the short members. In this paper the hybrid FEA formulation is extended to plate structures that are spot-welded to a frame comprised by tubular members. The new formulation is validated by comparing the hybrid FEA solution to results produced by very dense conventional FEA models in the mid-frequency range.
Technical Paper

A Hybrid Finite Element Formulation for Computing Structure-Borne Vibration in a Body-In-White

A new development in the area of the hybrid Finite Element Analysis (hybrid FEA) is presented. The hybrid FEA method combines the conventional FEA method with energy FEA (EFEA) for analysis of systems that contain both flexible and stiff members, and is suitable for mid-frequency computations. A formulation for analyzing flexible plates spot-welded to stiff beams when the excitation is applied on the stiff members is developed. Conventional FEA models are employed for modeling the behavior of the stiff members in a system. Appropriate damping elements are introduced in the connections between stiff and flexible members in order to capture the presence of the flexible members during the analyses of the stiff ones.
Technical Paper

A Load Transducer for Tire Cord

This paper discusses the measurement of cord loads in pneumatic tires using a direct load transducer. Such an instrument is described in detail together with results of numerous tests. Tire engineers will find this paper of value since it outlines methods for determining cord loads under actual tire operating conditions.
Technical Paper

A Market-Weighted Description of Low-Beam Headlighting Patterns in Europe

This study was designed to provide photometric information about current European low-beam headlamps. The sample included 20 low-beam headlamps manufactured for use on the 20 best-selling passenger vehicles for calendar year 1999 in 17 European countries. These 20 vehicles represent 47% of all vehicles sold in these countries. The lamps were purchased directly from vehicle dealerships, and photometered in 0.25° steps from 45° left to 45° right, and from 5° down to 7° up. The photometric information for each lamp was weighted by 1999 sales figures for the corresponding vehicle. The results are presented both in tabular form for the 25th-percentile, the median (50th-percentile), and the 75th-percentile luminous intensities, as well as in graphical form (for the median luminous intensities).
Technical Paper

A Market-Weighted Description of Low-Beam Headlighting Patterns in the U.S.

This study was designed to provide photometric information about current U.S. low-beam headlamps. The sample included 35 low-beam headlamps manufactured for use on the 23 best-selling passenger cars, light trucks, and vans for model year 1997. These 23 vehicles represent 45% of all vehicles sold in the U.S. The lamps were purchased directly from vehicle dealerships, and photometered in 0.5° steps from 45° left to 45° right, and from 5° down to 7° up. The photometric information for each lamp was weighted by 1997 sales figures for the corresponding vehicle. The results are presented both in tabular form for the 25th-percentile, the median (50th-percentile), and the 75th-percentile luminous intensities, as well as in graphical form (for the median luminous intensities, and median illuminance values reaching the road surface). The information is presented in aggregate form, as well as broken down by vehicle type and light source.
Technical Paper

A Multi-Variable High-Speed Imaging Study of Ignition Instabilities in a Spray-Guided Direct-Injected Spark-Ignition Engine

Ignition stability was studied in an optical spray guided spark ignition direct injection engine. The impact of intake air dilution with nitrogen, spark plug orientation, ignition system dwell time, and fuel injector targeting was addressed. Crank angle resolved fuel distributions were measured with a high-speed planar laser-induced fluorescence technique for hundreds of consecutive cycles. IMEP, COV of IMEP, burn rates and spark energy delivered to the gas were examined and used in conjunction with the imaging data to identify potential reasons for misfires.
Technical Paper

A Pilot Study of the Effects of Vertical Ride Motion on Reach Kinematics

Vehicle motions can adversely affect the ability of a driver or occupant to quickly and accurately push control buttons located in many advanced vehicle control, navigation and communications systems. A pilot study was conducted using the U.S. Army Tank Automotive and Armaments Command (TACOM) Ride Motion Simulator (RMS) to assess the effects of vertical ride motion on the kinematics of reaching. The RMS was programmed to produce 0.5 g and 0.8 g peak-to-peak sinusoidal inputs at the seat-sitter interface over a range of frequencies. Two participants performed seated reaching tasks to locations typical of in-vehicle controls under static conditions and with single-frequency inputs between 0 and 10 Hz. The participants also held terminal reach postures during 0.5 to 32 Hz sine sweeps. Reach kinematics were recorded using a 10-camera VICON motion capture system. The effects of vertical ride motion on movement time, accuracy, and subjective responses were assessed.
Technical Paper

A Research Design to Collect Data for a Second Generation Eyellipse

Current automotive design practices related to driver visibility are based on static laboratory studies of mostly straight ahead viewing that were conducted by Meldrum and others beginning in 1962. These individual studies have never been replicated either in the lab or in actual driving situations to determine the validity of their procedures. After a thorough review of the literature related to driver eye location and a statistical analysis of previous static eye location data, an experimental design is proposed to determine dynamic eye location distribution characteristics. This design will provide information on: (a) the relationship of static anthropometric measurements to dynamic eye location; (b) the difference between dynamic on-the-road eye location versus static in-the-lab eye location distributions: (c) the effect of different types of vehicle seating package parameters on eye location; and, (d) a validation of previous static eye location studies.
Technical Paper

A Survey of Alcohol as a Motor Fuel

Alcohol has been promoted and used as a motor fuel for more than 50 years. However, United States ethyl alcohol production is small compared with gasoline production. High latent heat of vaporization of alcohol makes possible some increase of power over gasoline. The heating value of alcohol is low and energy content of alcohol blends is less than that of gasoline; fuel consumption of blends is therefore increased. The ability of ethanol to improve the octane number of gasoline has diminished as the octane number of gasoline has improved. There is no published evidence that alcohols can appreciably reduce air pollution problems.
Technical Paper

A Survey of Automotive Occupant Restraint Systems: Where We’ve Been, Where We Are and Our Current Problems

In recent years, automotive occupant restraint system development has gained impetus, stimulated, in part, by new federal standards. But in the resolution of the basic question of whether automobiles should be equipped with restraints, many new problems have arisen, including, ironically, some brought on by regulation. While there is little doubt that restraint systems can provide the single most important contribution to occupant protection, such restraint systems remain useless unless adequately installed and properly worn. Current problems involve not only what concepts provide most promise for future restraint systems, but diverse and often conflicting industry and governmental opinion about what are the best interests of the motoring public. Restraints are still not provided in buses, trucks, and utility vehicles. In addition, the problems of child and infant restraints and restraints for retrofit in older vehicles remain unresolved.
Technical Paper

A Universal Heat Transfer Correlation for Intake and Exhaust Flows in an Spark-Ignition Internal Combustion Engine

In this paper, the available correlations proposed in the literature for the gas-side heat transfer in the intake and exhaust system of a spark-ignition internal combustion engine were surveyed. It was noticed that these only by empirically fitted constants. This similarity provided the impetus for the authors to explore if a universal correlation could be developed. Based on a scaling approach using microscales of turbulence, the authors have fixed the exponential factor on the Reynolds number and thus reduced the number of adjustable coefficients to just one; the latter can be determined from a least squares curve-fit of available experimental data. Using intake and exhaust side data, it was shown that the universal correlation The correlation coefficient of this proposed heat transfer model with all available experimental data is 0.845 for the intake side and 0.800 for the exhaust side.
Technical Paper

Absorption and Fluorescence Data of Acetone, 3-Pentanone, Biacetyl, and Toluene at Engine-Specific Combinations of Temperature and Pressure

Quantitative planar laser-induced fluorescence measurements of fuel/air mixing in engines are usually based on the use of fluorescence tracers. The strength of the signals often depends on temperature, pressure and mixture composition. This complicates a quantitative analysis. The use of a small-bore optical engine for fundamental studies of absorption and fluorescence properties of fluorescence tracers is described. The temperature, pressure and composition dependence of the spectra of toluene, acetone, 3-pentanone, and biacetyl are examined under motored conditions to extend the experimental data base for the development of comprehensive models that predict the strength of fluorescence signals for a given condition.
Technical Paper

Acceptance of Nonplanar Rearview Mirrors by U.S. Drivers

Five different nonplanar mirrors were evaluated as driver-side rearview mirrors in a field test using Ford employees. Two were spherical convex (differing in radius of curvature), and three were aspheric (differing primarily in the proportion of their surfaces over which radius of curvature was variable). Each participant drove for four weeks with one of the nonplanar mirrors. At three times during the test the participants filled out questionnaires concerning their experience with the mirrors. Driver preferences for the experimental mirrors increased moderately between surveys at one week and at four weeks. At four weeks, all five nonplanar mirrors were preferred to the standard flat mirror by at least a small amount. For each of the five mirror designs there was a large range of opinion. Most notably, a small number of people strongly disliked the aspheric design that involved the largest variable-radius area.
Technical Paper

Accounting for Manufacturing Variability in Interior Noise Computations

A formulation that accounts for manufacturing variability in the analysis of structural/acoustic systems is presented. The methodology incorporates the concept of fast probability integration with finite element (FEA) and boundary element analysis (BEA) for producing the probabilistic acoustic response of a structural/acoustic system. The advanced mean value method is used for integrating the system probability density function. FEA and BEA are combined for producing the acoustic response that constitutes the performance function. The probabilistic acoustic response is calculated in terms of a cumulative distribution function. The new methodology is used to illustrate the difference between the results from a probabilistic analysis that accounts for manufacturing uncertainty, and an equivalent deterministic simulation through applications. The probabilistic computations are validated by comparison to Monte Carlo simulations.
Technical Paper

Algorithmic Maintenance of a Diesel Engine Electronic Fuel Feed Controller by Criterion of the Content of Soot in Exhaust Gas

The feature of offered algorithm is that it allows, without record and analysis of the display diagram, to estimate a running cycle of a diesel engine parameters which characterize ecological and economic performances. The mathematical model described in report allows to determine connection of coefficient of filling, pressure and temperature of air boost, factor of excess of air with effectiveness ratio of combustion and contents of soot in exhaust gas and to take into account this connection at a choice initial data for control fuel feed or for elaboration of diesel engine dynamic model. The algorithm incorporated, for example, in the microcontroller of an electronic fuel feed controller allows analyzing the sensors data and theoretically determine of smoke amount in the exhaust gases for chosen cycle of fuel feed. The restriction of smoke is possible by criterion dD/dGT, where D - contents of soot in exhaust gas and GT - fuel cycle submission under the program-adaptive schema.