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Viewing 61 to 90 of 21019
2017-03-28
Journal Article
2017-01-0303
Ran Cai, Xueyuan Nie, Jingzeng Zhang
Light-weighting of vehicles is one of the challenges for transportation industry due to the increasing pressure of demands in better fuel economy and environment protection. Advanced high strength steels (AHSS) are considered as prominent material of choice to realize lightweight auto body and structures at least in near term. Stamping of AHSS with conventional die materials and surface coatings, however, results in frequent die failures and undesired panel surface finish. A chromium nitride (CrN) coating with plasma nitriding case hardened layer on a die material (duplex treatment) is found to offer good wear and galling resistances. The coating failure initiates from fatigue cracking on the coating surface due to cyclic sliding frictions. In this work, cyclic inclined sliding wear test was used to imitate a stamping process for study on development of coating fatigue cracking, including crack length and spacing vs. sliding-cycles and sliding energy densities.
2017-03-28
Journal Article
2017-01-0302
Saeid Nasheralahkami, Sergey Golovashchenko, Scott Dawson, Raj Sohmshetty
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.
2017-03-28
Journal Article
2017-01-0299
Chandra Jalluri, Himanshu Rajoria, Mark Goderis, Michael Habel, Trevor Hill
In automotive manufacturing, MQL (Minimum Quantity Lubricant) machining has been implemented on multi-axis CNC Machining Centers. In MQL machining, since there is no flood coolant, small quantities of coolant through spindle-tool is used at targeted cutting zones. However, a challenge that MQL machining faces is significant thermal growth of machine components (spindle, column, fixture etc) that must be appropriately addressed in order to achieve quality with tight tolerances. A strategy adopted by CNC OEMs is to measure the thermal growth and offset it during machining (machine thermal compensation). A gage bore is mounted in the machine fixture and its position measured using a probe. Required offsets are then calculated and applied for subsequent machining. Different OEMs use different methods for this gage bore-probe based referencing. It is imperative that this compensation be done correctly for it directly impacts quality.
2017-03-28
Journal Article
2017-01-0298
Allen Dobryden, Brian Rutter, Derek Hartl, Eric Bramson
Integration of a new, complex technology which crosses several powertrain subsystem boundaries (and thereby involves multiple organizations), without introducing inadvertent failure modes, can be a difficult task. This paper illustrates an approach to addressing this task at a system level using an example new technology. In product development activities involving primarily reuse of known technologies, perhaps with minor improvements, organizational and subsystem boundaries are generally clear. Interfaces are well established and responsibilities for failure mode avoidance are generally known. Implementation of a new technology which involves multiple parts of the organization, however, presents unique challenges to failure mode avoidance. The example technology primarily impacts the exhaust system, the powertrain cooling system, and the powertrain control system. It can affect engine operation, emissions, and performance.
2017-03-28
Journal Article
2017-01-0315
Yueqian Jia, Yangyang Qiao, Hao Pan, Edmund Chu, Yuanli Bai
A comprehensive plasticity and fracture model was built for metal sheets with application to sheet forming and vehicle crash simulations. The Bai-Wierzbicki (BW) plasticity model was extended consider material anisotropy, strain rate and high temperature effects in additional to the effect of multiaxial stress states. A fully modularized framework was established to combine isotropic, kinematic, and cross hardening behaviors under non-monotonic loading conditions. The modified Mohr-Coulomb (MMC) fracture model was extended to consider material anisotropy, high temperature effects and nonlinear strain path. The model has been implemented into Abaqus/Explicit as a user material subroutine (VUMAT). Test results on advanced high strength steels, aluminum alloy sheets and magnesium alloy sheets are used to validate the modeling and testing methodologies. Very good correlation was observed between experimental and simulation results.
2017-03-28
Journal Article
2017-01-0310
Wei Wu, Dajun Zhou, Donald Adamski, Darryl Young, Yu-Wei Wang
The die wear properties were investigated in real production condition using a prog-die with up to 70,000 hits using DP1180 steel. In total, 14 die inserts with the combination of 6 die materials and 5 coating methods of surface treatment were evaluated. The analytical results of die service life for each insert were provided by examining the surface condition of formed (flanged) part. 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 after 70,000 hits were characterized using Wyko NT110 machine. The current study provides the guidance for the die material and coating selections in successful stamping production using next generation AHSSs. Keywords: Die wear; Roughness; AHSS; Stamping, Die Surface Treatment, Die Steel
2017-03-28
Journal Article
2017-01-0126
Joshua W. Finn, John R. Wagner
Hybrid vehicle embedded systems and payloads require progressively more accurate and versatile thermal control mechanisms and strategies capable of withstanding harsh environments and increasing power density. The division of the cargo and passenger compartments into convective thermal zones which are independently managed can lead to a manageable temperature control problem. This study investigates the performance of a Peltier-effect thermoelectric zone cooling system to regulate the temperature of target objects (e.g., electronic controllers, auxiliary computer equipment) within ground vehicles. Multiple thermoelectric cooling modules (TEC) are integrated with convective cooling fans to provide chilled air for convective heat transfer from a robust, compact, and solid state device. A series of control strategies have been designed and evaluated to track a prescribed time varying temperature profile while minimizing power consumption.
2017-03-28
Journal Article
2017-01-0225
Gabriela Guerra, Ulises Figueroa-López, Andrea Guevara-Morales
The rapid growth of the emerging markets has pushed the automotive original equipment manufacturers to relocalize production to reduce manufacturing and logistic costs. To ensure an efficient and flexible supply chain, local suppliers are appointed. However, the characteristics of materials available in each region may have minor differences, and when geometry and process design recommendations that were developed for certain materials are implemented for materials under a different regional standard, different results are obtained. Such is the case of the clutch disc spacer bolt, in which its compression during riveting has a direct effect in the noise and vibration isolation of the vehicle.
2017-03-28
Journal Article
2017-01-0223
Haolong Liu, Weidong Wen, Xuming Su, Carlos Engler-Pinto, HongTae Kang
Morphological features of voids were characterized for T300/924 12-ply and 16-ply composite laminates at different porosity levels through the implementation of a digital microscopy (DM) image analysis technique. The composite laminates were fabricated through compression molding. Compression pressures of 0.1MPa, 0.3MPa, and 0.5MPa were selected to obtain composite plaques at different porosity levels. Tension-tension fatigue tests at load ratio R=0.1 for composite laminates at different void levels were conducted, and the dynamic stiffness degradation during the tests was monitored. Fatigue mechanisms were then discussed based on scanning electron microscope (SEM) images of the fatigue fracture surfaces. The test results showed that the presence of voids in the matrix has detrimental effects on the fatigue resistance of the material, depending on the applied load level.
2017-03-28
Journal Article
2017-01-0229
Hongyi Xu, Yang Li, Danielle Zeng
Process integration and optimization is the key enabler of the Integrated Computational Materials Engineering (ICME) of carbon fiber composites. In this work, automated workflows are developed for two types of composites: Sheet Molding Compounds (SMC) short fiber composites, and multi-layer unidirectional (UD) composites. For SMC, the proposed workflow integrates material processing simulation, microstructure representation volume element (RVE) models, material property prediction and structure preformation simulation to enable multiscale, multidisciplinary analysis and design. Processing parameters, microstructure parameters and vehicle subframe geometry parameters are defined as the design variables; the stiffness and weight of the structure are defined as the responses. For multi-layer UD structure, this work focuses on the discussion of different design representation methods and their impacts on the optimization performance.
2017-03-28
Journal Article
2017-01-0228
Yang Li, Zhangxing Chen, Hongyi Xu, Jeffrey Dahl, Danielle Zeng, Mansour Mirdamadi, Xuming Su
Compression molded SMC composed of chopped carbon fiber and resin polymer which balances the mechanical performance and manufacturing cost presents a promising solution for vehicle light-weighting strategy. However, the performance of the SMC molded parts highly depends on the compression molding process and local microstructure, which greatly increases the cost for the part level performance testing and elongates the design cycle. ICME (Integration Computational Material Engineering) approaches are thus necessary tools to reduce the number of experiments required during part design and speed up the deployment of the SMC materials. As the fundamental stage of the ICME workflow, commercial software packages for SMC compression molding exist yet remain not fully validated especially for chopped fiber systems. In the present study, SMC plaques are prepared through compression molding process.
2017-03-28
Journal Article
2017-01-0230
Louise A. Powell, William E. Luecke, Matthias Merzkirch, Katherine Avery, Tim Foecke
If carbon fiber reinforced polymers (CFRP) are to be used as structural components in lightweight automotive bodies, a robust understanding of how these materials absorb and dissipate energy during crash events must be developed. CFRPs are characterized by highly variable modulii and strengths and low ductilities, and thus mechanical measurements can be difficult. In this presentation we will detail novel experiments and equipment developed at NCAL for characterizing the interlaminar Mode I and II fracture energy release rates, the fracture stresses normal to the interfaces, and the high rate stress-strain behavior of unidirectional and woven composites. Digital image correlation (DIC) was used with unique test geometries to observe the micromechanisms of failure in these configurations, and these results will be discussed in light of numerical simulations of CFRP materials in crash conditions.
2017-03-28
Journal Article
2017-01-0242
Yakov Fradkin, Michel Cordonnier, Andrew Henry, David Newton
Ford Motor Company’s assembly plants build vehicles in a certain sequence. The planned sequence for the plant’s trim and final assembly area is developed centrally and is sent to the plant several days in advance. In this talk we present the study of two cases where the plant changes the planned sequence to cope with production constraints. In one case, a plant pulls ahead two-tone orders that require two passes through the paint shop. This is further complicated by presence in the body shop area of a unidirectional rotating tool that allows efficient build of a sequence “A-B-C” but heavily penalizes a sequence “C-B-A”. The plant changes the original planned sequence in the body shop area to the one that satisfies both pull-ahead and rotating tool requirements. In the other case, a plant runs on lean inventories. Material consumption is tightly controlled down to the hour to match with planned material deliveries.
2017-03-28
Journal Article
2017-01-0452
David A. Stephenson
Thermally sprayed engine bores require surface preparation prior to coating to ensure adequate adhesion. Mechanical roughening methods, in which a fine-scale dovetail profile is cut into the bore wall, produce surfaces which are easily gaged and are attractive for high volume. The currently available mechanical roughening methods are finish-boring based processes in which a standard boring insert is replaced with a PCD insert in which the roughening profile has been cut by EDM. These methods require diameter-specific tooling and significant clearance at the bottom of the bore for tool overtravel and retraction. This paper describes a new mechanical roughening method based on circular interpolation rather on finish boring. This method uses two tools: a side cutting end mill with peripheral grooves, which cuts a series of concentric grooves in the bore wall through interpolation, and a rotary swage which deforms the grooves to produce an undercut.
2017-03-28
Journal Article
2017-01-0477
Harish M. Rao, Jidong Kang, Garret Huff, Katherine Avery, Xuming Su
The use of carbon fiber reinforced polymer (CFRP) composites presents an attractive solution for automotive lightweighting due to the extensive weight savings. One of the key challenges to using CFRP for structural applications is developing and characterizing a robust joining technique for CFRP to metal sheets. Self-piercing rivet (SPR) has emerged as an economical and viable joining technique and is successfully used by the automotive industry in joining aluminum sheets. In this paper, the tensile and fatigue properties of continuous braided fiber CFRP to AA6011-T82 lap-shear SPRs are presented for joints produced with rivet head heights at two values within the nominal range. Even within the narrow range of head heights considered “nominal”, the rivet head piercing was found to have a dominant effect on both the tensile and fatigue properties of the lap-shear SPR joints.
2017-03-28
Journal Article
2017-01-0470
Lunyu Zhang, Shin-Jang Sung, Jwo Pan, Xuming Su, Peter Friedman
Structural stress solutions for flow drill screw (FDS) joints in lap-shear specimens of aluminum 6082-T6 sheets with and without clearance hole (without and with gap) are investigated. Analytical structural stress solutions at the critical locations of FDS joints based on the analytical solutions for a rigid inclusion in a thin plate under various loading conditions are first obtained. Finite element analyses are then conducted to verify the analytical solutions. The fatigue life estimations of the FDS joints in lap-shear specimens with and without clearance hole (without and with gap) based on the structural stress solutions are in agreement with those of the experimental results.
2017-03-28
Journal Article
2017-01-0475
Catherine Amodeo, Jwo Pan
The mode I and mode II stress intensity factor solutions for the pre-existing cracks near continuous and discontinuous gas metal arc welds in lap-shear specimens are investigated. Two-dimensional, plane strain finite element analyses were carried out in order to obtain the computational stress intensity factor solutions for the idealized and realistic weld geometries as the references. Then the stress intensity factor solutions for continuous and discontinuous welds were obtained by three-dimensional finite element analyses. The computational results indicate that the distributions of the mode I and mode II stress intensity factor solutions for the discontinuous weld are quite different from those for the continuous weld.
2017-03-28
Technical Paper
2017-01-0479
Soichi Hareyama, Ken-ichi Manabe, Makoto Nakashima, Takayuki Shimodaira, Akio Hoshi
In bolted joints, severe accidents caused by self-loosening frequently occur. The decrease tendency of the initial clamping force (axial tension) is thought to be the loosening phenomenon. For judgment of the self-loosening, the relative evaluation of locking device/method is performed by using Junker’s style loosening test equipment, for example. However, our basic question is "For how many tens of thousands of miles (operations), does the locking device maintain the clamping force before becoming loose?" This absolute evaluation on self-loosening is indispensable for the prediction of the lifetime to loosening failure and for the development of the product. From the author’s previous paper, there is a good linear relation on logarithmic coordinates between the decrease of clamping force ratio (measured /initial clamping force) and number of operations (or mileage or working time) since the last tightening.
2017-03-28
Technical Paper
2017-01-0506
Xueyuan Nie, Jimi Tjong
Ultra-high strength steel (UHSS) and magnesium (Mg) alloy have found their importance in response to automotive strategy of light weighting. UHSS to be metal-formed by hot stamping usually has a hot-dipped aluminum-silicon alloy layer on its surface to prevent the high temperature scaling during the hot stamping and corrosion during applications. In this paper, a plasma electrolytic oxidation (PEO) process was used to produce ceramic oxide coatings on aluminized UHSS and Mg with intention to further improve their corrosion resistances. A potentiodynamic polarization corrosion test was employed to evaluate general corrosion properties of the individual alloys. Galvanic corrosion of the aluminized UHSS and magnesium alloy coupling with and without PEO coatings was studied by a zero resistance ammeter (ZRA) test. It was found that the heating-cooling process simulating the hot stamping would reduce anti-corrosion properties of aluminized UHSS due to the outward iron diffusion.
2017-03-28
Journal Article
2017-01-1273
Qiang Dai, Jarod C. Kelly, Amgad Elgowainy
Vehicle lightweighting has been a focus of the automotive industry, as car manufacturers seek to comply with the corporate average fuel economy (CAFE) and the greenhouse gas (GHG) standards for MY 2017-2025 vehicles. However, when developing a lightweight vehicle design, the automotive industry typically targets maximum vehicle weight reduction at minimal capital cost. In this paper we consider the environmental impacts incurred by some of the lightweighting technology options. The materials generally 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
Technical Paper
2017-01-0471
Yasuo Kadoya, Yuki Oshino
By implementation of core technology of Capacitor-resistance welding, RingMash technology, metallic bonding, is developed to manufacture svarious components, the best suited for powertrain components such as transmission gears, at low cost. Components made by RingMash are attributed to smaller and lighter transmission. The technology is recommended to manufacture co-axle male-female work pieces bonding, male side diameter is slightly larger than female side hole. RingMashing is a solid state bonding without melting work piece. The actual RingMashing process is done in ambient atmosphere and does not use filler. RingMashing bonding process itself takes only 100 milliseconds, results very minimum Heat Affected Zone (HAZ), normally no more than 1 mm. The minimum HAZ achieves excellent structural integration for better performance of transmission. If two work pieces are same metals, sputtering free bonding is possible.
2017-03-28
Journal Article
2017-01-1513
Young-Chang Cho, Chin-Wei Chang, Andrea Shestopalov, Edward Tate
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 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
Journal Article
2017-01-1330
Youssef Ziada, Juhchin Yang, David DeGroat-Ives
Due 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. Significant 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. This paper presents approaches for predicting the dynamic flexibility for either of these assemblies using purely analytical approaches.
2017-03-28
Technical Paper
2017-01-0489
Hyunkwon Jo, Jongsoo Kim, Jaemin Park, Heeseung Yang, Hyunmin Park
Automotive industry faced the intense competition have been tried to lower product prices as well as satisfy performance in order to secure demands. Various ways to reduce manufacturing cost in this market environment have been approached, especially shortening manufacturing time has been mainly proposed. Because traditionally shortening manufacturing time activities took place in production sites, so they were not systematical and limited so the effect was less than expected. To overcome this, these activities should extend to development stage of product. Recently many plastic products have been widely used in automobile parts for light weight to improve fuel efficiency. The manufacturing process of such as plastic parts consists of injection molding and assembling parts. The process of injection molding process takes longer than other assembling if the product is big or complicated.
2017-03-28
Journal Article
2017-01-1276
Aditi Moorthy, Robert De Kleine, Gregory Keoleian, Jeremy Good, Geoff Lewis
The problem of accessibility to public transit is a well-documented problem in transportation theory and network literature known as the “Last Mile” problem. A lack of first and last mile specific transit services impairs access to public transit causing commuters to opt for private modes of transit over public modes of transit. This paper analyzes the implications of a shared autonomous vehicle (AV) taxi system providing last mile specific transit services in terms of environmental, cost, and performance metrics. Conventional public transit options along with a hypothetical last-mile shared autonomous vehicle (SAV) system are analyzed for transit between Ann Arbor and Detroit Wayne County Airport for life cycle energy, emissions, total travel time, and travel costs. In the case study, energy savings from using public transit options with AV last mile service were as high as 39% when compared to a personal vehicle (parking) option.
2017-03-28
Technical Paper
2017-01-0467
Wei Yuan, Brian Jordon, Bita Ghaffari, Harish Rao, Shengyi Li, Min Fan
Abstract Lightweight metals such as Al and Mg alloys have been increasingly used for reducing mass in both structural and non-structural applications in transportation industries. Joining these lightweight materials using traditional fusion welding techniques is a critical challenge for achieving optimum mechanical performance, due to degradation of the constituent materials properties during the process. Friction stir welding (FSW), a solid-state joining technique, has emerged as a promising method for joining these lightweight materials. In particular, high joining efficiency has been achieved for FSW of various Al alloys and Mg alloys separately. Recent work on FSW of dissimilar lightweight materials also show encouraging results based on quasi-static shear performance. However, coach-peel performance of such joints has not been sufficiently examined.
2017-03-28
Technical Paper
2017-01-0472
Gyoko Oh
Abstract To prevent corrosion of the inlet part with aqueous ammonia injection, high chromium corrosion-resistant materials have been applied for welded joints of mufflers. Bending fatigue strength of welded joint samples of flange pipes was defined through fatigue experiments, modeling that high fluctuating stresses exist in the inlet and outlet flange pipes of a muffler caused by the vibration of a moving vehicle. Factors that caused fatigue to failure such as welding bead shape and metallographic structure were identified through local stress measurements, FEM stress simulations, microscopic observations, and SEM-EDS composition analyses. By comparing with sample A having a smaller flank angle and sample B having a larger flank angle, the results suggested that the difference of bending fatigue strengths at 200,000 cycles was 24% when based on nominal stress, and the difference was 10% when based on measured maximum stress.
2017-03-28
Technical Paper
2017-01-0474
Chady Khalil, Yannick Amosse, Guillaume Racineux
Abstract In this study, a proposed new 3-in-1 process using the magnetic pulse welding (MPW) for welding similar and dissimilar metals and for hybrid joining between FRC and metals is developed. Welding between (a) AA1199 sheets and XES, (b) AA1199 and XSG which is zinc coated steel, (c) 5754-aluminum alloy and XES were performed and (d) hybrid joint between PA66-glass-FRC and 5754-aluminum was achieved. SEM observations and EDX analysis for the weld interface between aluminum and steel showed where detectable very thin layers of intermetallics and the wavy interface pattern typical for impact welding was identified. X-Ray microtomography observation for the joining region in the FRC showed the good state of the composite structure after joining. 3D numerical simulation using LS-Dyna was used for the selection of the welding parameters. Quasi-static lap shear testing for the welds revealed a failure in the weak metal sheet and not in the weld.
2017-03-28
Journal Article
2017-01-0478
Pai-Chen Lin, WeiNing Chen
Abstract Fatigue analysis of swept friction stir clinch (Swept-FSC) joints between 6061-T6 aluminum (Al) and S45C steel (Fe) sheets was conducted through experimental approaches. Before fatigue tests, a parametric study for the probe geometry of FSC tools was conducted in order to eliminate the hook structure inside the joint and improve the mechanical performance of the joint. Then a series of quasi-static and fatigue tests for Al/Fe Swept-FSC joints in lap-shear (LP) and cross-tension (CT) specimens were conducted. The fatigue data were recorded. The fatigue behavior of Al/Fe Swept-FSC joints in LP and CT specimens were examined through optical and scanning electron microscopes. Experimental results indicated that LP specimens have two failure modes, while CT specimens have only one failure mode. The dominant fatigue crack of each failure mode was identified.
2017-03-28
Journal Article
2017-01-1201
Zhenli Zhang, Zhihong Jin, Perry Wyatt
Lithium plating is an important failure factor for lithium ion battery with carbon-based anodes and therefore preventing lithium plating has been a critical consideration in designs of lithium ion battery and battery management system. The challenges are: How to determine the charging current limits which may vary with temperature, state of charge, state of health, and battery operations? Where are the optimization rooms in battery design and management system without raising plating risks? Due to the complex nature of lithium plating dynamics it is hard to detect and measure the plating by any of experimental means. In this work we developed an electrochemical model that explicitly includes lithium plating reaction. It enables both determination of plating onset and quantification of plating. We have studied the effects of charging pulses on homogenous plating in order to provide guidance for lithium ion battery design in hybrid applications.
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