Criteria

Text:
Affiliation:
Display:

Results

Viewing 1 to 30 of 1162
Technical Paper
2014-11-01
James E. Anderson, Timothy J. Wallington, Robert A. Stein, William M. Studzinski
Modification of gasoline blendstock composition in preparing ethanol-gasoline blends has a significant impact on vehicle exhaust emissions. In “splash” blending the blendstock is fixed, ethanol-gasoline blend compositions are clearly defined, and effects on emissions are relatively straightforward to interpret. In “match” blending the blendstock composition is modified for each ethanol-gasoline blend to match one or more fuel properties. The effects on emissions depend on which fuel properties are matched and what modifications are made, making trends difficult to interpret. The purpose of this paper is to illustrate that exclusive use of this approach has fundamental flaws. For typical gasolines without ethanol, the distillation profile is a smooth, roughly linear relationship of temperature vs. percent fuel distilled. Hence the use of three points on the curve (T10, T50, and T90, defined as the 10%v, 50%v, and 90%v evaporated temperatures) has been sufficient to define their volatility-related behavior in engines.
Technical Paper
2014-10-13
Julien Manin, Scott Skeen, Lyle Pickett, Eric Kurtz, James E. Anderson
The purpose of this study is to characterize extended lift-off combustion in a controlled engine combustion simulation facility using selected fuels of different cetane number, oxygen content, molecular structure, and blend ratio. Ignition delay time, lift-off length and soot KL extinction have been measured for ambient and injector operating conditions relevant to modern diesel engines. The experiments compared different fuel blends made of n-hexadecane, n-dodecane, methyldecanoate, TPGME, as well as m-xylene. Several optical diagnostics have been used simultaneously to monitor the ignition, combustion and soot formation/oxidation processes from spray flames from different fuels. The results confirmed the impact of oxygenated fuels on combustion, with a slight reduction in ignition delay times and a strong impact on soot formation. It has been observed that the changes in ignition timing and lift-off length, generally associated with changes in soot production levels were not following a direct relationship.
Technical Paper
2014-10-13
Antonino La Rocca, David MacMillan, Paul Shayler, Michael Murphy, Ian Pegg
Cold idle operation of a modern design light duty diesel engine and the effect of multiple pilot injections on stability were investigated. Magnitude and cycle-to-cycle variation of indicated parameter have been used as key indicators of cold idle performance. The utility of different injection strategies, up to three pilot injections before a main, is investigated. The investigation was initially carried out experimentally at 1000rpm, a speed representative of idle conditions, and at -20ºC. Benefits of mixture preparation were initially explored by a heat release analysis performed for each case. A CFD investigation was then used to visualise the effect of multiple pilots on in-cylinder mixture distribution, with particular emphasis on how the injection patterns affect the mixture distribution in the proximity of the glow plug. Kiva 3v was used to model the combustion system and fuel injections. A 60º mesh was used taking advantage of rotational symmetry. Combustion system and injector arrangements mimic the HPCR diesel engine used in the experimental investigation.
Technical Paper
2014-09-28
Jaroslaw Grochowicz, Carlos Agudelo, Shanglei Li, Harald Abendroth, Karl-Heinz Wollenweber, Achim Reich
Abstract The efforts of the ISO “Test Variability Task Force” have been aimed at improving the understanding and at reducing brake dynamometer test variability during performance testing. In addition, dynamometer test results have been compared and correlated to vehicle testing. Even though there is already a vast amount of anecdotal evidence confirming the fact that different procedures generate different friction coefficients on the same brake corner, the availability of supporting data to the industry has been elusive up to this point. To overcome this issue, this paper focuses on assessing friction levels, friction coefficient sensitivity, and repeatability under ECE, GB, ISO, JASO, and SAE laboratory friction evaluation tests. With multiple companies (or programs) developing and assessing the friction coefficient and friction behavior under different methods, it is inevitable to avoid conflicts of performance requirements or lack of reproducibility or correlation of test results under different test methods.
Article
2014-07-16
Ram’s official move to adopt the SAE J2807 towing standard for validating all three (1500, 2500, and 3500) of its pickup weight classes raises the competitive bar for the industry's other pickup players. Meanwhile, Ford has engineered its latest F-450 with half the GCVW capability of a Class-8 tractor-trailer.
Training / Education
2014-04-14
Julian Blair, Gregory Banish, Chi Binh La, Talus Park
Driven by the need for lower emissions, better fuel economy and improved drive quality, optimized powertrain calibrations are required for the many different vehicle configurations on today's roadways. While powertrain components such as the internal combustion engine, transmission, and hybrid electric powertrain are somewhat familiar to the automotive industry, the control theory, calibrations and system interactions between these components are a relatively unfamiliar aspect. This web seminar will introduce participants to the concepts behind optimized powertrain calibrations and how they impact fuel consumption, exhaust emissions, and vehicle performance.
Technical Paper
2014-04-01
Sharon Leach, Mark Jennings
Abstract A new performance simulation capability has been developed for powersplit HEVs to enable analytical assessment of new engine technologies in the context of HEV system operation and to analyze/understand important system dynamics and control interactions affecting HEV performance. This new capability allows direct simulation with closed-loop controls and the driver, is compatible with Ford standard HEV system simulation capabilities and enables simulation with multiple levels of model fidelity and feature content across the vehicle system. The combined plant Vehicle Model Architecture (VMA) in Simulink was used for the infrastructure. The simulation capability includes a Dymola model of the powersplit transaxle, a Vehicle System Control (VSC) model implemented in Simulink, a high fidelity 2L Atkinson GT-Power engine model, and a simplified representation of the engine controls in Simulink. Also, the simulation capability interfaces to Ford standard vehicle data sets for HEVs through a Matlab interface.
Technical Paper
2014-04-01
Hiroko Ohtani, Khaled Zreik, Edgar Steigerwald, Martin Knaffel, Robert Neumann, Gordon P. Small, Gregory Mordukhovich, Tracey E. King
Under the initiative of The United States Council for Automotive Research LLC (USCAR) [1], we have developed and run comprehensive friction tests of dual clutch transmission fluids (DCTFs). The focus of this study is to quantify the anti-shudder durability over a simulated oil life of 75,000 shifts. We have evaluated six DCT fluids, including 2 fluids with known field shudder performance. Six different tests were conducted using a DC motor-driven friction test machine (GK test bench): 1. Force Controlled Continuous Slip, 2. Dynamic Friction, 3. Speed controlled Acceleration-Deceleration, 4. Motor-torque controlled Acceleration-Deceleration, 5. Static Friction, and 6. Static Break-Away. The test fluids were aged (with the clutch system) on the test bench to create a realistic aging of the entire friction system simultaneously. The Force Controlled Continuous Slip mode has demonstrated a correlation with anti-shudder performance in the field, whereas other tests revealed important properties such as torque capacity and shift qualities.
Technical Paper
2014-04-01
Bert Bras, Andrew Carlile, Thomas Niemann, Sherry Mueller, Hyung Chul Kim, Timothy Wallington, Heidi McKenzie, Susan Rokosz
Abstract Tools are now publicly available that can potentially help a company assess the impact of its water use and risks in relation to their global operations and supply chains. In this paper we describe a comparative analysis of two publicly available tools, specifically the WWF/DEG Water Risk Filter and the WBCSD Global Water Tool that are used to measure the water impact and risk indicators for industrial facilities. By analyzing the risk assessments calculated by these tools for different scenarios that include varying facilities from different industries, one can better gauge the similarities and differences between these water strategy tools. Several scenarios were evaluated using the water tools, and the results are compared and contrasted. As will be shown, the results can vary significantly.
Technical Paper
2014-04-01
Claire Boland, Robb DeKleine, Aditi Moorthy, Gregory Keoleian, Hyung Chul Kim, Ellen Lee, Timothy J. Wallington
Abstract Automakers have the opportunity to utilize bio-based composite materials to lightweight cars while replacing conventional, nonrenewable resource materials. In this study, Life Cycle Assessment (LCA) is used to understand the potential benefits and tradeoffs associated with the implementation of bio-based composite materials in automotive component production. This cradle-to-grave approach quantifies the fiber and resin production as well as material processing, use, and end of life for both a conventional glass-reinforced polypropylene component as well as a cellulose-reinforced polypropylene component. The comparison is calculated for an exterior component on a high performance vehicle. The life cycle primary energy consumption and global warming potential (GWP) are evaluated. Reduced GWP associated with the alternative component are due to the use of biomass as process energy and carbon sequestration, in addition to the alternative material component's lightweighting effect.
Technical Paper
2014-04-01
Tae-Kyung Lee, Ghamdan Kaid, John Blankenship, Dyche Anderson
Abstract Aggressive battery usage profiles in electrified vehicle applications require extensive efforts in developing battery management strategy and system design determination to guarantee safe operation under every real-world driving conditions. Experiment based approaches have been widely used for battery system development, but higher costs and longer testing time restrain the number of test cases in the product development process. Battery experiments tend to be conservative to avoid inherent risks of battery failure modes under aggressive battery operation close to the capability limits. Battery Hardware-In-the-Loop (HIL) is an alternative way to overcome the limitations of experiment-based approaches. Battery models in the HIL should provide real-time computation capability and high (at least acceptable) prediction accuracy. Equivalent circuit model (ECM) based HILs have been used owing to its relatively good balance between computational time and prediction accuracy. However, there are difficulties in constructing compact ECM structures to capture reliable battery responses over wide ranges of State of Charge (SOC), current, and temperature.
Technical Paper
2014-04-01
Ienkaran Arasaratnam, Jimi Tjong, Saeid Habibi
Abstract No two battery cells can be identical. Charging/discharging a battery pack without monitoring cell voltages or SoC (State-of-Charge) will cause cell voltages to deviate over time and the packs useable capacity to decrease quickly. To redistribute charge uniformly among cells, various cell balancing methods have been proposed in the literature. In this paper, a cell balancing method based on a single switched-capacitor is presented from a brand new perspective. Unlike the traditional balancing methods that rely on the voltage divergence criterion, this paper uses the SoC divergence criterion to shuttle charge from a highly charged cell to a poorly charged cell. Moreover, an equivalent resistance of the single-switched capacitor topology is derived in steady state. For fast cell balancing, design guidelines are provided for selecting a proper switching-time period and the capacitor parameters. Ultracapacitors are recommended to achieve this goal. To demonstrate the effectiveness of the proposed method, numerous simulations are performed on a string of five series connected Lithium-ion cells that have different initial SoCs and electrochemical parameters.
Technical Paper
2014-04-01
Hangsheng Hou
Abstract The purpose of this work is to analytically investigate automotive exhaust system noise generation and propagation phenomena. The turbulent exhaust gas flow interacts with the exhaust system structure, and as a result of this interaction, the structure vibrates and radiates noise. In the meantime, pressure wave becomes acoustic wave at its outlet. This study focuses on an exhaust system and carrying out transient fluid-structure analysis by using an explicit finite element solver that is capable of solving the Navier Stokes equations for turbulent, compressible viscous fluids as well as the field equations for solid structures in a fully coupled fashion. The time domain signals obtained from the transient analysis are post-processed to yield frequency domain data, sound pressure levels, noise source pattern as well as the selected acoustic field contour snapshots. The work involves evaluating different design proposals and comparing their corresponding sound pressure levels and acoustic fields.
Technical Paper
2014-04-01
Louis Tijerina, James Sayer
Abstract The objectives of this study were a) to determine how expert judges categorized valid Integrated Vehicle-Based Safety Systems (IVBSS) Forward Collision Warning (FCW) events from review of naturalistic driving data; and b) to determine how consistent these categorizations were across the judges working in pairs. FCW event data were gathered from 108 drivers who drove instrumented vehicles for 6 weeks each. The data included video of the driver and road scene ahead, beside, and behind the vehicle; audio of the FCW alert onset; and engineering data such as speed and braking applications. Six automotive safety experts examined 197 ‘valid’ (i.e., conditions met design intent) FCW events and categorized each according to a taxonomy of primary contributing factors. Results indicated that of these valid FCW events, between 55% and 73% could be considered ‘nuisance alerts’ by the driver. These were the FCW alerts presented in benign conditions (e.g., lead-vehicle turning) or as a result of deliberate driver action (aggressive driving).
Technical Paper
2014-04-01
Yanan Zhao, Thomas Rambow, Chat Nguyen, Mathew Boesch, Raymond Spiteri, Kyle Post
Abstract The safety monitor is a high integrity control that monitors the health and performance of safety related computer controlled functions in vehicles. The integrity of the safety monitor code is critical to the overall performance of the control software. Traditionally, once monitor requirements are understood, then the safety monitor is hand coded or created in a modeling environment. New practices such as ISO 26262 prescribe formal or semiformal methods are used against certain classes of foreseeable faults. Recently, a new tool, which is capable of auto-generating C-code based on safety monitor formal functional requirements is available from BTC Company. Ford Motor Company investigated the tool using an application example from a powertrain control feature safety monitor. The paper describes a pilot project and process assessment, comprising the steps of requirement-based C-code generation, code integration, code analysis and code verification using requirements selected from the powertrain control feature's specification.
Technical Paper
2014-04-01
Lawrence Banasky
Abstract In an effort to reduce the cost and time associated with bench level automotive electrical and electromagnetic compatibility (EMC) validation tests, a survey was created to request advice from the test labs that perform this testing. The survey focuses particularly on the development of the test plan document and the preparation of the test setup. The survey was sent to a targeted group of individuals with experience in performing this type of testing. The invitees work at laboratories that represent the majority of labs in the world that are authorized to perform component electrical / EMC validation testing for automotive original equipment manufacturers (OEMs). There were a significant number of responses; it is possible that representatives from all of the invited laboratories responded. The survey results provide demographic information about the test labs and their participants. The participants possess a tremendous amount of test experience and are therefore qualified to provide recommendations on the subject.
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
Guangning(Gary) Gao
Abstract Distance to empty (DTE) estimation is an important factor to electric vehicle (EV) applications due to its limited driving range. The DTE calculation is based on available energy of the battery and power usage by the powertrain components (e.g. electric motor) and climate control components (e.g. PTC heater and electric AC compressor). The conventional way of estimating the DTE is to treat the power consumed by the climate control system the same as the power by the powertrain for either instantaneous or rolling average estimation. The analysis in this study shows that the power consumption by the climate control system should be estimated based on the current ambient conditions and driver's input instead of using the recorded data from the past driving cycles. The climate control should also be considered separately from the powertrain in power usage rolling average calculation, which results in improvements in DTE estimation especially for extreme hot and cold conditions. Additionally, the climate control power consumption shows unique characteristics during the initial period of cabin climate control.
Technical Paper
2014-04-01
Joy H Forsmark
Abstract High ductility cast aluminum alloys are seeing more use in vehicles as a greater effort is made to replace components made from heavier steel and iron alloys with lighter weight alloys such as aluminum. High ductility cast aluminum has significant advantages by allowing for complex shape and considerable consolidation of parts in body structures. However, joining can be a challenge because one popular method for aluminum joining, self-piercing riveting (SPR), requires a ductility of greater than 10%, forcing the common high ductility Al alloys to undergo a T6 heat treatment which adds cost and potential distortion issues to Al component. In this study, friction stir spot welding was investigated as a potential joining technique for this material in the as-cast condition. Samples of as-cast Aural-2™ alloy were joined to Aural-2™, 5754, and 6061 alloys, to determine the manufacturing feasibility, weld strength, and fatigue strength using this joining technique.
Technical Paper
2014-04-01
Hangsheng Hou
Abstract When a window opens to provide the occupant with fresh air flow while driving, wind throb problems may develop along with it. This work focuses on an analytical approach to address the wind throb issue for passenger vehicles when a front window or sunroof is open. The first case of this paper pertains to the front window throb issue for the current Ford Escape. Early in a program stage, CAA (Computational Aeroacoustics) analysis predicted that the wind throb level exceeded the program wind throb target. When a prototype vehicle became available, the wind tunnel test confirmed the much earlier analytical result. In an attempt to resolve this issue, the efforts focused on a design proposal to implement a wind spoiler on the side mirror sail, with the spoiler dimension only 6 millimeters in height. This work showed that the full vehicle CAA analysis could capture the impact of this tiny geometry variation on the wind throb level inside the vehicle cabin. The independent wind tunnel effort came to the same conclusion, and the difference between the analysis and testing is only about 1 dB.
Technical Paper
2014-04-01
Ali Seyed Yaghoubi, Paul Begeman, Golam Newaz, Derek Board, Yijung Chen, Omar Faruque
Abstract The present investigation details an experimental procedure for frontal impact responses of a generic steel front bumper crush can (FBCC) assembly subjected to a rigid full and 40% offset impact. There is a paucity of studies focusing on component level tests with FBCCs, and of those, speeds carried out are of slower velocities. Predominant studies in literature pertain to full vehicle testing. Component level studies have importance as vehicles aim to decrease weight. As materials, such as carbon fiber or aluminum, are applied to vehicle structures, computer aided models are required to evaluate performance. A novel component level test procedure is valuable to aid in CAE correlation. All the tests were conducted using a sled-on-sled testing method. Several high-speed cameras, an IR (Infrared) thermal camera, and a number of accelerometers were utilized to study impact performance of the FBCC samples. A linear potentiometer was installed next to each crush-can to directly measure crush length of the can.
Technical Paper
2014-04-01
Monica Majcher, Hongyi Xu, Yan Fu, Ching-Hung Chuang, Ren-Jye Yang
Vehicle restraint system design is a difficult optimization problem to solve because (1) the nature of the problem is highly nonlinear, non-convex, noisy, and discontinuous; (2) there are large numbers of discrete and continuous design variables; (3) a design has to meet safety performance requirements for multiple crash modes simultaneously, hence there are a large number of design constraints. Based on the above knowledge of the problem, it is understandable why design of experiment (DOE) does not produce a high-percentage of feasible solutions, and it is difficult for response surface methods (RSM) to capture the true landscape of the problem. Furthermore, in order to keep the restraint system more robust, the complexity of restraint system content needs to be minimized in addition to minimizing the relative risk score to achieve New Car Assessment Program (NCAP) 5-star rating. These call for identifying the most appropriate multi-objective optimization algorithm to solve this type of vehicle restraint system design problem.
Technical Paper
2014-04-01
Danielle Zeng, Cedric Xia, Jeffrey Webb, Li Lu, Yuan Gan, Xianjun Sun, John Lasecki
Abstract Long glass fiber reinforced (LGFR) composites have been widely used in automotive industry to reduce vehicle weight and maintain relatively high mechanical performances. Due to the injection molding process, the distribution of fiber orientations varies at different locations and through the panel thickness, resulting in anisotropic and non-uniform mechanical properties. The current practice of computer modeling of these materials is generally using isotropic properties adjusted by a certain scale factor. The effect of fiber orientation is not carefully considered due to the complexity of fiber orientation distribution in the LGFR parts. The purpose of this paper is to identify key factors affecting vehicle attribute performances where LGFR composites are used; and provide an efficient way for accurate CAE modeling of LGFR composites. In this study, tensile coupons cut from a simple geometric injection molded plaque are tested. The tested material properties are compared to those from CAE predictions to understand how well the CAE predictions capture the material behavior with fiber orientation accounted for.
Technical Paper
2014-04-01
Hoda Eiliat, Xueyuan Nie, Jimi Tjong, Julio Villafuerte
Abstract This research focuses on study of feasibility of using ceramic oxide coatings on the cylinder wall of hypoeutectic aluminum silicon alloy engine blocks. Coatings are achieved in an aqueous electrolytic bath and composed of both alpha and gamma phases of Al2O3 and have shown promising wear resistance. Composition and acidity level of the electrolyte creates a variation of surface roughness, coating hardness and thickness which has direct influence on the wear behavior of the sliding surfaces. The effect of load bearing and coating morphology on coefficient of friction was studied. SEM images of the substrate showed no predominant wear behavior or delamination. Coefficient of friction and wear rate were also measured. This study shows the importance of surface structure on oil retention and wear rate. Coarser coatings can be desirable under starved oil condition since they show lower coefficient of friction. This can be explained due to the oil retention structure of coarse coatings with more topographical variance.
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
Tadanori Yanai, Xiaoye Han, Meiping Wang, Graham T. Reader, Ming Zheng, Jimi Tjong
Abstract The study investigated the characteristics of the combustion, the emissions and the thermal efficiency of a direct injection diesel engine fuelled with neat n-butanol. Engine tests were conducted on a single cylinder four-stroke direct injection diesel engine. The engine ran at 6.5 bar IMEP and 1500 rpm engine speed. The intake pressure was boosted to 1.0 bar (gauge), and the injection pressure was controlled at 60 or 90 MPa. The injection timing and the exhaust gas recirculation (EGR) rate were adjusted to investigate the engine performance. The effect of the engine load on the engine performance was also investigated. The test results showed that the n-butanol fuel had significantly longer ignition delay than that of diesel fuel. n-Butanol generally led to a rapid heat release pattern in a short period, which resulted in an excessively high pressure rise rate. The pressure rise rate could be moderated by retarding the injection timing and lowering the injection pressure. The applicable window of the injection timing for the n-butanol fuel was much narrower than that of the conventional diesel fuel because of the constraints of misfiring and excessive pressure rise rate.
Technical Paper
2014-04-01
Satheesh Makkapati, Eric Curtis
Abstract Naturally aspirated Homogeneous Charge Compression Ignition (HCCI) operational window is very limited due to inherent issues with combustion harshness. Load range can be extended for HCCI operation using a combination of intake boosting and cooled EGR. Significant range extension, up to 8bar NMEP at 1000RPM, was shown to be possible using these approaches in a single cylinder engine running residual trapping HCCI with 91RON fuel with a 12:1 compression ratio. Experimental results over the feasible speed / load range are presented in this paper for a negative valve overlap HCCI engine. Fuel efficiency advantage of HCCI was found to be around 15% at 2.62bar / 1500RPM over a comparable SI engine operating at the same compression ratio, and the benefit was reduced to about 5% (best scenario) as the load increased to 5bar at the same speed. The primary intention of this paper is to evaluate the compatibility of the presented HCCI concept in a future downsized and boosted engine for improving fuel efficiency over typical drive cycles.
Technical Paper
2014-04-01
Chen Fang, Xipeng Wang, Qi Dai, Yi Murphey, David Weber, Perry MacNeille
Abstract New vehicle control algorithms are needed to meet future emissions and fuel economy mandates that are quite likely to require a measurement of ambient specific humidity (SH). Current practice is to obtain the SH by measurement of relative humidity (RH), temperature and barometric pressure with physical sensors, and then to estimate the SH using a fit equation. In this paper a novel approach is described: a system of neural networks trained to estimate the SH using data that already exists on the vehicle bus. The neural network system, which is referred to as a virtual SH sensor, incorporates information from the global navigation satellite system such as longitude, latitude, time and date, and from the vehicle climate control system such as temperature and barometric pressure, and outputs an estimate of SH. The conclusion of this preliminary study is that neural networks have the potential of being used as a virtual sensor for estimating ambient and intake manifold's SH.
Technical Paper
2014-04-01
Hongyi Xu, Monica T. Majcher, Ching-Hung Chuang, Yan Fu, Ren-Jye Yang
Abstract Response Surface Model (RSM)-based optimization is widely used in engineering design. The major strength of RSM-based optimization is its short computational time. The expensive real simulation models are replaced with fast surrogate models. However, this method may have some difficulties to reach the full potential due to the errors between RSM and the real simulations. RSM's accuracy is limited by the insufficient number of Design of Experiments (DOE) points and the inherent randomness of DOE. With recent developments in advanced optimization algorithms and High Performance Computing (HPC) capability, Direct Multidisciplinary Design Optimization (DMDO) receives more attention as a promising future optimization strategy. Advanced optimization algorithm reduces the number of function evaluations, and HPC cut down the computational turnaround time of function evaluations through fully utilizing parallel computation. In this paper, we test the performance of RSM-based optimization and DMDO using multiple benchmark problems of both analytical mathematical examples and a vehicle design.
Technical Paper
2014-04-01
Raed E. El-jawahri, Tony R. Laituri, Agnes S. Kim, Stephen W. Rouhana, Para V. Weerappuli
In the present study, transfer equations relating the responses of post-mortem human subjects (PMHS) to the mid-sized male Hybrid III test dummy (HIII50) under matched, or nearly-identical, loading conditions were developed via math modeling. Specifically, validated finite element (FE) models of the Ford Human Body Model (FHBM) and the HIII50 were used to generate sets of matched cases (i.e., 256 frontal impact cases involving different impact speeds, severities, and PMHS age). Regression analyses were subsequently performed on the resulting age-dependent FHBM- and HIII50-based responses. This approach was conducted for five different body regions: head, neck, chest, femur, and tibia. All of the resulting regression equations, correlation coefficients, and response ratios (PHMS relative to HIII50) were consistent with the limited available test-based results.
Viewing 1 to 30 of 1162

Filter

  • Range:
    to:
  • Year: