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Viewing 91 to 120 of 9023
2017-03-28
Technical Paper
2017-01-1704
D.J. Branagan, A.E. Frerichs, B.E. Meacham, S. Cheng, A.V. Sergueeva
Abstract Automotive OEMs are compelled by increasingly stringent global emissions standards to find economic solutions for building higher efficiency vehicles without compromising safety and ride quality. This challenge requires new advanced high strength steels (AHSS) that will significantly reduce vehicle weight and improve fuel economy. In addition to providing higher strength, these automotive sheet steels must have exceptional formability to produce reduced gauge parts with increasingly complex geometries. Formability is comprised of two components, global and local. Global formability represents the ability of a sheet material to be deformed under various stress conditions and to be formed into a part without failure. It can be estimated using forming-limit diagrams or ductility measurements from conventional uniaxial tensile tests. However, these tests cannot reliably assess the local formability at the edges or at the internal holes of the blanks during stamping.
2017-03-28
Technical Paper
2017-01-1706
Sandeep Bhattacharya, Daniel Green, Raj Sohmshetty, Ahmet Alpas
Abstract Automobile body panels made from advanced high strength steel (AHSS) provide high strength-to-mass ratio and thus AHSS are important for automotive light-weighting strategy. However, in order to increase their use, the significant wear damage that AHSS sheets cause to the trim dies should be reduced. The wear of dies has undesirable consequences including deterioration of trimmed parts' edges. In this research, die wear measurement techniques that consisted of white-light optical interferometry methods supported by large depth-of-field optical microscopy were developed. 1.4 mm-thick DP980-type AHSS sheets were trimmed using dies made from AISI D2 steel. A clearance of 10% of the thickness of the sheets was maintained between the upper and lower dies. The wear of the upper and lower dies was evaluated and material abrasion and chipping were identified as the main damage features at the trim edges.
2017-03-28
Technical Paper
2017-01-1703
Ryan A. Howell, Richard Gerth
Abstract Fe-Mn-Al-C steel alloys have been previously studied for their potential as an alternative steel alloy for Rolled Homogeneous Armor (RHA). Prior examination of the material system has shown promise in this capacity due to the high strength and reduced density of Mn steels as compared to RHA. The prior tested materials were both wrought and cast versions but were all less than an inch in thickness. The alloy is once again being examined, but this time in thicker wrought plate. The aim of the current body of work is to develop a Military Specification (MIL-SPEC) for this new class of ballistically capable material. For industry and communities interested in such material development, the purpose of this paper, then, is to provide a summary of the processing parameters, the prior ballistic and dynamic material testing, cutting and welding approaches, and the extent of progress on industrial sized thick plate development.
2017-03-28
Journal Article
2017-01-1705
Hua-Chu Shih, Dajun Zhou, Bruce Konopinski
Abstract The hole piercing process is a simple but important task in manufacturing processes. The quality requirement of the pierced hole varies between different applications. It can be either the size or the edge quality of the hole. Furthermore, the pierced hole is often subject to a secondary forming process, in which the edge stretchability is of a main concern. The recently developed advanced high strength steels (AHSS) and ultra high strength steels (UHSS) have been widely used for vehicle weight reduction and safety performance improvements. Due to the higher strength nature of these specially developed sheet steels, the hole piercing conditions are more extreme and challenging, and the quality of the pierced hole can be critical due to their relatively lower edge stretching limits than those for the conventional low and medium strength steels.
2017-03-28
Technical Paper
2017-01-1708
Saeid Nasheralahkami, Sergey Golovashchenko, Collin Malek, Erika Rugh, Daniel Kowalsky, Weitian Zhou
Abstract In recent years, dual phase (DP) Advanced High Strength Steels (AHSS) and Ultra High Strength Steels (UHSS) are considered as prominent materials in the automotive industry due to superior structural performance and vehicle weight reduction capabilities. However, these materials are often sensitive to trimmed edge cracking if stretching along sheared edge occurs in such processes as stretch flanging. Another major issue in the trimming of UHSS is tool wear because of higher contact pressures at the interface between cutting tools and sheet metal blank caused by UHSS’s higher flow stresses and the presence of a hard martensitic phase in the microstructure. The objective of the current paper is to study the influence of trimming conditions and tool wear on quality and stretchability of trimmed edge of DP980 steel sheet. For this purpose, mechanically trimmed edges were characterized for DP980 steel and compared with other steels such as HSLA 350 and BH210.
2017-03-28
Journal Article
2017-01-1707
C. Matthew Enloe, Jason Coryell, Jeff Wang
Abstract Retained austenite stability to both mechanically induced transformation and athermal transformation is of great importance to the fabrication and in-vehicle performance of automotive advanced high strength steels. Selected cold-rolled advanced high strength steels containing retained austenite with minimum tensile strengths of 980 MPa and 1180 MPa were pre-strained to pre-determined levels under uniaxial tension in the rolling direction and subsequently cooled to temperatures as low as 77 K. Room temperature uniaxial tensile results of pre-strained and cooled steels indicate that retained austenite is stable to athermal transformation to martensite at all tested temperatures and pre-strain levels. To evaluate the combined effects of temperature and pre-strain on impact behavior, stacked Charpy impact testing was conducted on the same 980 MPa minimum tensile strength steel following similar pre-straining in uniaxial tension.
2017-03-28
Technical Paper
2017-01-1726
Sameer Shah, Aayoush Sharma, Raghav Angra, Nitin Singh, Khalique Ahmed
Abstract In an unavoidable event of a suspect being chased by police, there is high probability for the criminal to evade the police while driving his vehicle. At many instances, criminal escapes without leaving a trail behind and becomes untraceable. A new concept of Vigilance Assistance System Network (VASN) has been developed, which is spread across the city and helps in catching the escaping criminals. At every junction, the traffic-signals are installed with a microcontroller chip and these connected traffic signals form a network with distinct city areas demarcated on the map. The vehicle is installed with GPS and a RFID module on their ECU when it approaches any intersection or junction; they receive wireless signals from traffic-signals and transmit another registering signal to the traffic-light wirelessly through RFID.
2017-03-28
Technical Paper
2017-01-1732
Payodh Dwivedi
Abstract The conventional hybrid engine faces one major problem i.e. high cost of production. Although hybrid engines, in many sense proved to be highly efficient and environmental friendly, but high cost of production makes them less feasible and limits their applications. This problem is overcome by a new design in which instead of having Internal Combustion(IC) engine and electric motor separately, these two are incorporated under same housing. This involves a different working mechanism of electric motor which is as described below- This mechanism is applied to a normal engine which has two or more than two cylinders in any configuration or orientation. Taking example of In-line four cylinder engines as it is most widely used. In this the two cylinders work on conventional internal combustion mechanism, but the other two cylinders are electric cylinder and works on electricity.
2017-03-28
Technical Paper
2017-01-1665
Qigui Wang, Peggy Jones, Yucong Wang, Dale Gerard
Abstract With the increasing use of aluminum shape castings in structural applications in automobiles, assurance of cast product integrity and performance has become critical in both design and manufacturing. In this paper, the latest understanding of the relationship between casting quality and mechanical properties of aluminum castings is summarized. Examples of newly developed technologies for alloy design, melting and melt treatment, casting and heat treatment processes in aluminum casting are reviewed. Robust design and development of high integrity aluminum castings through an Integrated Computational Materials Engineering (ICME) approach is also discussed.
2017-03-28
Technical Paper
2017-01-1666
David Weiss, Orlando Rios
Abstract Aluminum alloys containing cerium have excellent castability and retain a substantial fraction of their room temperature strength at temperatures of 200°C and above. High temperature strength is maintained through a thermodynamically trapped, high surface energy intermetallic. Dynamic load partitioning between the aluminum and the intermetallic increases mechanical response. Complex castings have been produced in both permanent mold and sand castings. This versatile alloy system, using an abundant and inexpensive co-product of rare earth mining, is suitable for parts that need to maintain good properties when exposed to temperatures between 200 and 315°C.
2017-03-28
Technical Paper
2017-01-1663
Alan Druschitz, Christopher Williams, Erin Connelly, Bob Wood
Abstract Binder jetting of sand molds and cores for metal casting provides a scalable and efficient means of producing metal components with complex geometric features made possible only by Additive Manufacturing. Topology optimization software that can mathematically determine the optimum placement of material for a given set of design requirements has been available for quite some time. However, the optimized designs are often not manufacturable using standard metal casting processes due to undercuts, backdraft and other issues. With the advent of binder-based 3D printing technology, sand molds and cores can be produced to make these optimized designs as metal castings.
2017-03-28
Technical Paper
2017-01-1677
Bharathi Krishnamoorthy, Jacob Eapen, Santosh kshirsagar, Giri Nammalwar, Torsten Wulf, Miguel Mancilla
Abstract Automotive industry is witnessing a significant growth in the number of Electronic Control Units (ECUs) and its features owing to the focused inclination towards customer preference, comfort, safety, environmental friendliness and governmental regulations. The software components are booming as the pivotal to cater to the technology-driven trends such as diverse mobility, autonomous driving, electrification, and connectivity. This necessitates exhaustive testing to ensure quality of the system as any unpredictable failures may impose severe financial and market risk on the OEM. The industry has largely supplemented Hardware-in-the-loop (HIL) testing to manual testing considering the testing constraints posed by the latter. Automation trends complement the demand for quick yet exhaustive testing prior to the market launch.
2017-03-28
Journal Article
2017-01-1642
Don Price
Abstract The force required to assemble automotive electrical connectors has been tested using a range of mating speeds in a controlled lab environment. This set of tests answers questions often brought up regarding how mating speed significantly influences the required applied force. Data from these evaluations show small but consistent mate force changes with assembly speed. Sealed and unsealed connectors were found to respond differently to mating speed, which is explained using a theoretical analysis. The mechanical analysis explains what forces are involved and how they are influenced by speed. Practical recommendations are given on how mate force testing should be done to assure results are as useful as possible. Results show that that mating speed has a positive correlation to peak mate force. An opposite, negative, correlation for unsealed connectors was found.
2017-03-28
Journal Article
2017-01-1513
Young-Chang Cho, Chin-Wei Chang, Andrea Shestopalov, Edward Tate
Abstract The airflow into the engine bay of a passenger car is used for cooling down essential components of the vehicle, such as powertrain, air-conditioning compressor, intake charge air, batteries, and brake systems, before it returns back to the external flow. When the intake ram pressure becomes high enough to supply surplus cooling air flow, this flow can be actively regulated by using arrays of grille shutters, namely active grille shutters (AGS), in order to reduce the drag penalty due to excessive cooling. In this study, the operation of AGS for a generic SUV-type model vehicle is optimized for improved fuel economy on a highway drive cycle (part of SFTP-US06) by using surrogate models. Both vehicle aerodynamic power consumption and under-hood cooling performance are assessed by using PowerFLOW, a high-fidelity flow solver that is fully coupled with powertrain heat exchanger models.
2017-03-28
Technical Paper
2017-01-1537
Ananya Bhardwaj
Abstract Improving brake cooling has commanded substantial research in the automotive sector, as safety remains paramount in vehicles of which brakes are a crucial component. To prevent problems like brake fade and brake judder, heat dissipation should be maximized from the brakes to limit increasing temperatures. This research is a CFD investigation into the impact of existing wheel center designs on brake cooling through increased cross flow through the wheel. The new study brings together the complete wheel and disc geometries in a single CFD study and directly measures the effect on brake cooling, by implementing more accurately modeled boundary conditions like moving ground to replicate real conditions correctly. It also quantifies the improvement in the cooling rate of the brake disc with a change in wheel design, unlike previous studies.
2017-03-28
Technical Paper
2017-01-1529
Nicholas Simmonds, John Pitman, Panagiotis Tsoutsanis, Karl Jenkins, Adrian Gaylard, Wilko Jansen
Abstract Cooling drag, typically known as the difference in drag coefficient between open and closed cooling configurations, has traditionally proven to be a difficult flow phenomenon to predict using computational fluid dynamics. It was seen as an academic yardstick before the advent of grille shutter systems. However, their introduction has increased the need to accurately predict the drag of a vehicle in a variety of different cooling configurations during vehicle development. This currently represents one of the greatest predictive challenges to the automotive industry due to being the net effect of many flow field changes around the vehicle. A comprehensive study is presented in the paper to discuss the notion of defining cooling drag as a number and to explore its effect on three automotive models with different cooling drag deltas using the commercial CFD solvers; STARCCM+ and Exa PowerFLOW.
2017-03-28
Technical Paper
2017-01-1323
Jerry Lai, Youssef Ziada, Juhchin Yang
Abstract In the assembly of axles and wheel hubs, a nut is frequently used to fasten them as one unit. In order for the nut to hold the assembly in its final position, crimping is a widely-used method which prevents nut from loosening. A reliable crimping process not only prevents movement of the nut during axle operation but should also minimize the possibility of cracking the rim. If the nut cracks during assembly, it can start to rust and deteriorate. The service life span of the axle assembly hence shortens as a result. The quality of crimping operation is determined by the component designs, the process parameters, and the crimping tool geometry. It would be time-consuming and costly to evaluate these factors empirically; let alone the requirement of prototypes in the early stage of a new program. A dynamic finite element methodology which adopts the Arbitrary Lagrangian-Eulerian formulation from ABAQUS explicit solver is developed to simulate the complete crimping process.
2017-03-28
Technical Paper
2017-01-1321
Meisam Mehravaran, Yi Zhang
Abstract Degas bottles have been extensively used in vehicles in order to act as an air pillow on top of the cooling loop and provide space for expansion. One of the important characteristics of the bottle which defines if it will work in a certain loop is the so called “capacity” of the bottle which defines the flowrate that degas bottle would be able to pass through without any foaming. Considering the complex geometry of degas bottle and the foaming phenomena, predicting the behavior of coolant in the bottle passages is challenging which requires costly tests. Computational Fluid Dynamics (CFD) has been extensively used in simulating multi-phase flows in automotive components. In the current project, CFD has been used to simulate the behavior of flow in bottle chambers and to provide guidelines for the design team in order to increase the bottle performance/capacity. The CFD guidelines were in agreement with test results and lead to improving the degas bottle capacity.
2017-03-28
Journal Article
2017-01-1330
Youssef Ziada, Juhchin Yang, David DeGroat-Ives
Abstract Owing to decreased development cycle timing, designing components for manufacturability has never been as important. Assessing manufacturing feasibility has therefore become an increasingly important part of new product engineering. This manufacturing feasibility is conventionally assessed based on static stiffness of components and fixture assemblies. However, in many operations, excess vibration represents the actual limitation on processing a workpiece. Limits on how far into components a tool can reach or the amount of processing time required to machine a feature is commonly decreased significantly due to vibration. Critical time is spent resolving these vibration problems during product launches. Depending on the machining configurations these vibrations can be due to the part & work support structure or due to the tooling & spindle assembly.
2017-03-28
Journal Article
2017-01-1271
David Wright, John Henshaw, Nia R. Harrison, S. George Luckey
Abstract High-strength aluminum alloys such as 7075 can be formed using advanced manufacturing methods such as hot stamping. Hot stamping utilizes an elevated temperature blank and the high pressure stamping contact of the forming die to simultaneously quench and form the sheet. However, changes in the thermal history induced by hot stamping may increase this alloy’s stress corrosion cracking (SCC) susceptibility, a common corrosion concern of 7000 series alloys. This work applied the breaking load method for SCC evaluation of hot stamped AA7075-T6 B-pillar panels that had been artificially aged by two different artificial aging practices (one-step and two-step). The breaking load strength of the specimens provided quantitative data that was used to compare the effects of tensile load, duration, alloy, and heat treatment on SCC behavior.
2017-03-28
Journal Article
2017-01-1273
Qiang Dai, Jarod C. Kelly, Amgad Elgowainy
Abstract Vehicle lightweighting has been a focus of the automotive industry, as car manufacturers seek to comply with corporate average fuel economy (CAFE) and greenhouse gas (GHG) emissions standards for model year (MY) 2017-2025 vehicles. However, when developing a lightweight vehicle design, the automotive industry typically targets maximum vehicle weight reduction at minimal cost increase. In this paper, we consider the environmental impacts of the lightweighting technology options. The materials used for vehicle lightweighting include high-strength steel (HSS), aluminum, magnesium and carbon fiber reinforced plastic (CFRP). Except for HSS, the production of these light materials is more GHG-intensive (on a kg-to-kg basis) compared with the conventional automotive materials they substitute. Lightweighting with these materials, therefore, may partially offset the GHG emission reductions achieved through improved fuel economy.
2017-03-28
Journal Article
2017-01-1278
Keisuke Isomura
Abstract In the automobile industry, interest in the prevention of global warming has always been high. The development of eco cars (HV, EV etc.), aimed at reducing CO2 emissions during operation, has been progressing. In the announcement of its "Toyota Environmental Challenge 2050", Toyota declared its commitment to creating a future in which people, cars, and nature coexist in harmony. In this declaration, Toyota committed to reducing CO2 emissions not only during operation but also over the entire life cycle of vehicles, and to using resources effectively based on a 4 R’s approach (refuse, reduce, reuse, and recycle). Although eco cars decrease CO2 emissions during operation, most of them increase CO2 emissions during manufacturing. For example, the rare-earths (Nd, Dy etc.) used in the magnets of driving motors are extracted through processes that produce a significant amount of CO2 emissions.
2017-03-28
Journal Article
2017-01-1277
Jakobus Groenewald, Thomas Grandjean, James Marco, Widanalage Widanage
Abstract Increasingly international academic and industrial communities desire to better understand, implement and improve the sustainability of vehicles that contain embedded electrochemical energy storage. Underpinning a number of studies that evaluate different circular economy strategies for the electric vehicle (EV) battery system are implicit assumptions about the retained capacity or State-of-Health (SoH) of the battery. International standards and best-practice guides exist that address the performance evaluation of both EV and HEV battery systems. However, a common theme in performance testing is that the test duration can be excessive and last for a number of hours. The aim of this research is to assess whether energy capacity and internal resistance measurements of Li-ion based modules can be optimized, reducing the test duration to a value that may facilitate further End-of-Life (EoL) options.
2017-03-28
Technical Paper
2017-01-1372
Bo Wang, Smruti Panigrahi, Mayur Narsude, Amit Mohanty
Abstract Increasing number of vehicles are equipped with telematics devices and are able to transmit vehicle CAN bus information remotely. This paper examines the possibility of identifying individual drivers from their driving signatures embedded in these telematics data. The vehicle telematics data used in this study were collected from a small fleet of 30 Ford Fiesta vehicles driven by 30 volunteer drivers over 15 days of real-world driving in London, UK. The collected CAN signals included vehicle speed, accelerator pedal position, brake pedal pressure, steering wheel angle, gear position, and engine RPM. These signals were collected at approximately 5Hz frequency and transmitted to the cloud for offline driver identification modeling. A list of driving metrics was developed to quantify driver behaviors, such as mean brake pedal pressure and longitudinal jerk. Random Forest (RF) was used to predict driver IDs based on the developed driving metrics.
2017-03-28
Journal Article
2017-01-1472
Niels Pasligh, Robert Schilling, Marian Bulla
Abstract Rivets, especially self-piercing rivets (SPR), are a primary joining technology used in aluminum bodied vehicles. SPR are mechanical joining elements used to connect sheets to create a body in white (BiW) structure. To ensure the structural performance of a vehicle in crash load cases it is necessary to describe physical occurring failure modes under overloading conditions in simulations. One failure mode which needs to be predicted precisely by a crash simulation is joint separation. Within crash simulations a detailed analysis of a SPR joint would require a very high computational effort. The conflict between a detailed SPR joint and a macroscopic vehicle model needs to be solved by developing an approach that can handle an accurate macroscopic prediction of SPR behavior with a defined strength level with less computational effort. One approach is using a cohesive material model for a SPR connection.
2017-03-28
Technical Paper
2017-01-0307
Xiaohua Hu, Xin Sun, Sergey Golovashchenko
Abstract The hole stretchability of two Aluminum Alloys (AA6111 and AA6022) are studied by using a two stages integrated finite element framework where the edge geometry and edge damages from the hole piercing processes were considered in the subsequent hole expansion processes. Experimentally it has been found that AA6022 has higher hole expansion ratios than those of AA6111. This observation has been nicely captured by finite element simulations. The main cause of differences have been identified to the volume fractions of the random distributed second phase hard particles which play a critical role in determining the fracture strains of the materials.
2017-03-28
Technical Paper
2017-01-0308
Hyunok Kim, Jianhui Shang, James Dykeman, Anoop Samant, Clifford Hoschouer
Abstract Practical evaluation and accurate prediction of edge cracking are challenging issues in stamping AHSS for automotive body structures. This paper introduces a new hole-expansion testing method that could be more relevant to the edge cracking problem observed in stamping AHSS. A new testing method adopted a large hole diameter of 75 mm compared to the ISO standard hole diameter of 10 mm. A larger hole diameter was determined to be sensitive to edge cracking using the finite element method (FEM) based sensitivity analyses with various hole sizes. A die punching tool was developed to replicate typical production blanking conditions. An inline monitoring system was developed to visually monitor the hole edge cracking during the test and synchronize with the load-displacement data. Two AHSS materials, DP980 and TRIP780, and an aluminum alloy, A1 5182-O, were experimentally evaluated.
2017-03-28
Technical Paper
2017-01-0309
Mitchell Rencheck, Paul Zelenak, Jianhui Shang, Hyunok Kim
Abstract Aluminum alloys are increasingly utilized in automotive body panels and crash components to reduce weight. Accurately assessing formability of the sheet metal can reduce design iteration and tooling tryouts to obtain the desired geometry in aluminum stampings. The current ISO forming limit curve (FLC) procedure is a position dependent technique which produces the FLC based on extrapolation at the crack location. As aluminum sheet metal use increases in manufacturing, accurate determination of the forming limits of this material will be necessary prior to production. New time dependent methods using digital imaging correlation (DIC) account for variations in material behavior by continuously collecting strain data through the material necking point. This allows more accurate FLC determination that is necessary for efficient design in the automotive stamping industry.
2017-03-28
Journal Article
2017-01-0310
Wei Wu, Dajun Zhou, Donald Adamski, Darryl Young, Yu-Wei Wang
Abstract The die wear up to 80,800 hits on a prog-die setup for bare DP1180 steel was investigated in real production condition. In total, 31 die inserts with the combination of 11 die materials and 9 coatings were evaluated. The analytical results of die service life for each insert were provided by examining the evolution of surface wear on inserts and formed parts. The moments of appearance of die defects, propagation of die defects, and catastrophic failure were determined. Moreover, the surface roughness of the formed parts for each die insert was characterized using Wyko NT110 machine. The objectives of the current study are to evaluate the die durability of various tooling materials and coatings for flange operations on bare DP 1180 steel and update OEM tooling standards based on the experimental results. The current study provides the guidance for the die material and coating selections in large volume production for next generation AHSSs.
2017-03-28
Journal Article
2017-01-0302
Saeid Nasheralahkami, Sergey Golovashchenko, Scott Dawson, Raj Sohmshetty
Abstract In recent years, implementation of dual phase (DP) Advanced High Strength Steels (AHSS) and Ultra High Strength Steels (UHSS) is increasing in automotive components due to their superior structural performance and vehicle weight reduction capabilities. However, these materials are often sensitive to trimmed edge cracking if stretching along sheared edge occurs in such processes as stretch flanging. Tool wear is another major issue in the trimming of UHSS because of higher contact pressures at the interface between cutting tools and sheet metal blank caused by UHSS’s higher flow stresses and the presence of a hard martensitic in the microstructure. The objective of the present paper is to discuss the methodology of analyzing die wear for trimming operations of UHSS components and illustrate it with some examples of tool wear analysis for trimming 1.5mm thick DP980 steel.
Viewing 91 to 120 of 9023