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Technical Paper

Some Observations on the International Coalition Strategies in the Development of Chinese Automobile Industry

Since the end of W.W.II, many countries have embarked on various to develop a national automobile industry to spur the economic growth of the country, to meet the rising domestic demand for automobiles, and to compete in the world markets. Can these countries achieve these objectives and at the same time retain their national independence in the automobile industry from the domination of the foreign multinational automobile manufacturers? This paper addresses these questions by examining first, the records of Latin America (Argentina, Brazil, Mexico), South Korea and Taiwan in Asia Pacific Region; it then attempts to determine to what extent their experiences may be transferrable to the Chinese automobile industry which is currently undergoing modernization. For the purpose of this paper, the automobile industry encompasses only passenger vehicles.
Technical Paper

Advanced Anthropomorphic Test Device Concept Definition

This paper summarizes the results of Phase 1, Concept Definition, of the AATD program and identifies the reasons such a new test device is needed. The following areas are addressed: 1) injury priority from accident data; 2) current dummy design, use, and potential improvements; and 3) technical characteristics and design concepts for a new AATD, its data processing, and its certification systems.
Technical Paper

Minimizing Read-Through When Creating a Mechanical Score in a Polymer Skin

When weakening a skin/foam bilaminate by mechanically scoring the polymer skin on its back surface, where it is bonded to the foam, the weakness of the bilaminate is determined by the depth of the score groove. The deeper the groove, the weaker the bilaminate. But also, the deeper the groove, the greater the tendency for read-through. Read-through is seeing on the front surface the location of this groove that was created on the back surface. Scored skins, after mounting flat on a glass plate, were viewed with an optical interferometer. It was found that the topographical feature that constituted read-through was a valley. A Silly Putty model was used to better understand the strains induced by mechanical scoring and this understanding was used to identify factors affecting read-through. Blade thickness and the ultimate elongation of the skin material were identified as factors. This work is applicable to certain types of passenger-side seamless airbag systems, for example.
Technical Paper

Permanent Mold Casting and Creep Behavior of Mg - 4 Al - 4 X: (Ca, Ce, La, Sr) Alloys

Creep-resistant magnesium alloys for automotive powertrain applications offer significant potential for vehicle weight reduction. In this study permanent mold casting, microstructure and creep behavior have been investigated for a series of ternary magnesium alloys (Mg-4Al-4X (X: Ca, Ce, La, Sr) wt%) and AXJ530 (Mg-5Al-3Ca-0.15Sr, wt%). A permanent mold was instrumented with twelve thermocouples and mold temperature was monitored during the casting process. Average mold temperature increased from 200°C to 400°C during a typical alloy casting series (fifteen to twenty castings). The cast microstructure for all alloys consists of primary α-Mg globular phase surrounded by eutectic structure which is composed of intermetallic(s) and α-Mg magnesium phases. The primary cell size of the AXJ530 increased from 18 to 24 μm with increasing mold temperature and a similar trend is expected for all alloys.
Technical Paper

Interior Aircraft Noise Computations due to TBL Excitation using the Energy Finite Element Analysis

The Energy Finite Element Analysis (EFEA) has been developed for evaluating the vibro-acoustic behavior of complex systems. In the past EFEA results have been compared successfully to measured data for Naval, automotive, and aircraft systems. The main objective of this paper is to present information about the process of developing EFEA models for two configurations of a business jet, performing analysis for computing the vibration and the interior noise induced from exterior turbulent boundary layer excitation, and discussing the correlation between test data and simulation results. The structural EFEA model is generated from an existing finite element model used for stress analysis during the aircraft design process. Structural elements used in the finite element model for representing the complete complex aircraft structure become part of the EFEA structural model.
Technical Paper

Load Limits with Fuel Effects of a Premixed Diesel Combustion Mode

Premixed diesel combustion is intended to supplant conventional combustion in the light to mid load range. This paper demonstrates the operating load limits, limiting criteria, and load-based emissions behavior of a direct-injection, diesel-fueled, premixed combustion mode across a range of test fuels. Testing was conducted on a modern single-cylinder engine fueled with a range of ultra-low sulfur fuels with cetane number ranging from 42 to 53. Operating limits were defined on the basis of emissions, noise, and combustion stability. The emissions behavior and operating limits of the tested premixed combustion mode are independent of fuel cetane number. Combustion stability, along with CO and HC emissions levels, dictate the light load limit. The high load limit is solely dictated by equivalence ratio: high PM, CO, and HC emissions result as overall equivalence ratio approaches stoichiometric.
Technical Paper

Probabilistic Computations for the Main Bearings of an Operating Engine Due to Variability in Bearing Properties

This paper presents the development of surrogate models (metamodels) for evaluating the bearing performance in an internal combustion engine. The metamodels are employed for performing probabilistic analyses for the engine bearings. The metamodels are developed based on results from a simulation solver computed at a limited number of sample points, which sample the design space. An integrated system-level engine simulation model, consisting of a flexible crankshaft dynamics model and a flexible engine block model connected by a detailed hydrodynamic lubrication model, is employed in this paper for generating information necessary to construct the metamodels. An optimal symmetric latin hypercube algorithm is utilized for identifying the sampling points based on the number and the range of the variables that are considered to vary in the design space.
Technical Paper

Integrating a Particle Swarm Optimizer in a Multi-Discipline Design Optimization Environment for Conceptual Ship Design

A particle swarm optimization (PSO) solver is developed based on theoretical information available from the literature. In the main new effort presented in this paper, an approach is developed for integrating the PSO algorithm as a driver at both the top and the discipline levels of a multidisciplinary design optimization (MDO) framework which is based on the Target Cascading (TC) method. The integrated MDO/PSO algorithm is employed for analyzing a multidiscipline optimization statement reflecting the conceptual ship design problem from the literature. The results, the strengths, and the weaknesses of the integrated MDO/PSO algorithm are discussed as related to conceptual ship design.
Technical Paper

Modeling Iso-octane HCCI Using CFD with Multi-Zone Detailed Chemistry; Comparison to Detailed Speciation Data Over a Range of Lean Equivalence Ratios

Multi-zone CFD simulations with detailed kinetics were used to model iso-octane HCCI experiments performed on a single-cylinder research engine. The modeling goals were to validate the method (multi-zone combustion modeling) and the reaction mechanism (LLNL 857 species iso-octane) by comparing model results to detailed exhaust speciation data, which was obtained with gas chromatography. The model is compared to experiments run at 1200 RPM and 1.35 bar boost pressure over an equivalence ratio range from 0.08 to 0.28. Fuel was introduced far upstream to ensure fuel and air homogeneity prior to entering the 13.8:1 compression ratio, shallow-bowl combustion chamber of this 4-stroke engine. The CFD grid incorporated a very detailed representation of the crevices, including the top-land ring crevice and head-gasket crevice. The ring crevice is resolved all the way into the ring pocket volume. The detailed grid was required to capture regions where emission species are formed and retained.
Technical Paper

Structure-borne Vehicle Analysis using a Hybrid Finite Element Method

The hybrid FEA method combines the conventional FEA method with the energy FEA (EFEA) for computing the structural vibration in vehicle structures when the excitation is applied on the load bearing stiff structural members. Conventional FEA models are employed for modeling the behavior of the stiff members in the vehicle. In order to account for the effect of the flexible members in the FEA analysis, appropriate damping and spring/mass elements are introduced at the connections between stiff and flexible members. Computing properly the values of these damping and spring/mass elements is important for the overall accuracy of the computations. Utilizing in these computations the analytical solutions for the driving point impedance of infinite or semi-infinite members introduces significant approximations.
Technical Paper

Validation of the Human Motion Simulation Framework: Posture Prediction for Standing Object Transfer Tasks

The Human Motion Simulation Framework is a hierarchical set of algorithms for physical task simulation and analysis. The Framework is capable of simulating a wide range of tasks, including standing and seated reaches, walking and carrying objects, and vehicle ingress and egress. In this paper, model predictions for the terminal postures of standing object transfer tasks are compared to data from 20 subjects with a wide range of body dimensions. Whole body postures were recorded using optical motion capture for one-handed and two-handed object transfers to target destinations at three angles from straight ahead and three heights. The hand and foot locations from the data were input to the HUMOSIM Framework Reference Implementation (HFRI) in the Jack human modeling software. The whole-body postures predicted by the HFRI were compared to the measured postures using a set of measures selected for their importance to ergonomic analysis.
Technical Paper

Modeling Ascending and Descending Stairs Using the Human Motion Simulation Framework

The Human Motion Simulation Framework (Framework) is a hierarchical set of algorithms for predicting and analyzing task-oriented human motion. The Framework was developed to improve the performance of commercial human modeling software by increasing the accuracy of predicted motions and the speed of generating simulations. This paper presents the addition of stair ascending and descending to the Transition Stepping and Timing (Transit) model, a component of the Framework that predicts gait and acyclic stepping.
Technical Paper

Human-rating Automated and Robotic Systems — How HAL Can Work Safely with Astronauts

Long duration human space missions, as planned in the Vision for Space Exploration, will not be possible without applying unprecedented levels of automation to support the human endeavors. The automated and robotic systems must carry the load of routine “housekeeping” for the new generation of explorers, as well as assist their exploration science and engineering work with new precision. Fortunately, the state of automated and robotic systems is sophisticated and sturdy enough to do this work — but the systems themselves have never been human-rated as all other NASA physical systems used in human space flight have. Our intent in this paper is to provide perspective on requirements and architecture for the interfaces and interactions between human beings and the astonishing array of automated systems; and the approach we believe necessary to create human-rated systems and implement them in the space program.
Journal Article

In-Cylinder Particulate Matter and Spray Imaging of Ethanol/Gasoline Blends in a Direct Injection Spark Ignition Engine

A single-cylinder Direct Injection Spark Ignition (DISI) engine with optical access was used to investigate the effects of ethanol/gasoline blends on in-cylinder formation of particulate matter (PM) and fuel spray characteristics. Indolene was used as a baseline fuel and two blends of 50% and 85% ethanol (by volume, balance indolene) were investigated. Time resolved thermal radiation (incandescence/natural luminosity) of soot particles and fuel spray characteristics were recorded using a high speed camera. The images were analyzed to quantify soot formation in units of relative image intensity as a function of important engine operating conditions, including ethanol concentration in the fuel, fuel injection timing (250, 300 and 320° bTDC), and coolant temperature (25°C and 90°C). Spatially-integrated incandescence was used as a metric to quantify the level of in-cylinder PM formed at the different operating conditions.
Technical Paper

Parametric Reduced-Order Models of Battery Pack Vibration Including Structural Variation and Pre-Stress Effects

The goal of this work is to develop an efficient numerical modeling method for the vibration of hybrid electric vehicle (HEV) battery packs to support probabilistic forced response simulations and fatigue life predictions. There are two important sources of variations in HEV battery packs that affect their structural dynamic response. One source is the uncertain level of pre-stress due to bolts or welds used for joining cells within a pack. The other source is small structural variations among the cells of a battery pack. The structural dynamics of HEV battery packs are known to feature very high modal density in many frequency bands. That is because packs are composed of nominally identical cells. The high modal density combined with small, random structural variations among the cells can lead to drastic variations in the dynamic response compared with those of the ideal nominal system.
Technical Paper

Vehicle Airborne Noise Analysis Using the Energy Finite Element Method

The Energy Finite Element Analysis (EFEA) has been developed for computing the structural vibration and the interior noise level of complex structural-acoustic systems by solving numerically governing differential equations with energy densities as primary variables. In this paper a complete simulation process for evaluating airborne noise in an automotive vehicle is presented and validated through extensive comparison to test data. The theoretical elements associated with the important paths of the noise transfer from the exterior of the vehicle to the interior acoustic space are discussed. The steps required for developing an EFEA model for a vehicle are presented. The model is developed based on the physical construction of the vehicle system and no test measurements are utilized for adjusting the numerical model.
Journal Article

The Effect of Age on Fat and Bone Properties along the Vertebral Spine

The human body changes as it becomes older. The automotive safety community has been interested in understanding the effect of aging on restraint performance. Recent research has been focused on assessing the structural and material changes associated with age. In this study, structural tissue distribution was determined using the computed tomography (CT) scan data of more than 19,000 patients, aged 16 and up. The data consisted of subcutaneous fat cross-sectional area, visceral fat cross-sectional area, and trabecular bone density taken at each vertebral level. The data was quantified as a function of five age groups with the youngest group defined as 16-29 years old and the oldest group as 75 and up. An additional analysis stratified on gender was carried out. Overall, visceral fat increased with age.
Technical Paper

Level Crossing Probabilities for Cyclostationary Processes with Two Frequencies in Marine Diesel Engine Shafting Systems

A solution is proposed to the upcrossing problem for a stress of a special form encountered in probabilistic torsional vibration analysis of marine Diesel engine shafting systems. For the case that two engine criticals occur at the same engine speed, the stress is modeled as a cyclostationary random process with two frequencies. An equivalent stationary process is defined, requiring that its envelope process has the same upcrossing rate as the envelope of the original cyclostationary random process. It is assumed that both processes have the same probability of upcrossing a specific threshold in a given time interval. Numerical implementation shows the applicability and efficiency of the method.
Journal Article

Effects of Material Properties on Static Load-Deflection and Vibration of a Non-Pneumatic Tire During High-Speed Rolling

The Michelin Tweel tire structure has recently been developed as an innovative non-pneumatic tire which has potential for improved handling, grip, comfort, low energy loss when impacting obstacles and reduced rolling resistance when compared to a traditional pneumatic tire. One of the potential sources of vibration during rolling of a non-pneumatic tire is the buckling phenomenon and snapping back of the spokes in tension when they enter and exit the contact zone. Another source of noise was hypothesized due to a flower petal ring vibration effect due to discrete spoke interaction with the ring and contact with the ground during rolling as the spokes cycle between tension and compression. Transmission of vibration between the ground force, ring and spokes to the hub was also considered to be a significant contributor to vibration and noise characteristics of the Tweel.
Technical Paper

A Comparative Study on Sound Transmission Loss and Absorption Coefficient of Acoustical Materials

Acoustical materials are widely used in automotive vehicles and other industrial applications. Two important parameters namely Sound Transmission Loss (STL) and absorption coefficient are commonly used to evaluate the acoustical performance of these materials. Other parameters, such as insertion loss, noise reduction, and loss factors are also used to judge their performance depending on the application of these materials. A systematic comparative study of STL and absorption coefficient was conducted on various porous acoustical materials. Several dozen materials including needled cotton fiber (shoddy) and foam materials with or without barrier/scrim were investigated. The results of STL and absorption coefficient are presented and compared. As expected, it was found that most of materials are either good in STL or good in absorption. However, some combinations can achieve a balance of performance in both categories.