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2017-03-28
Journal Article
2017-01-0306
Brandon M. Hance
Until now the hole expansion ratio has been generally regarded as a relative “local formability” parameter with limited application to edge-cracking analysis and prediction. In this study a constrained statistical hole expansion test data analysis methodology is introduced, where the lower-bound hole expansion ratio is the basis for three practical edge-cracking failure criteria. The Maximum Edge Stretch Criterion is directly compatible with CAE simulation. The Edge Thinning Limit Criterion and the Critical Thickness Criterion are more useful in field work and post mortem laboratory failure analysis. Several case studies are described, where hole expansion test data are used to analyze edge cracking of Advanced High Strength Steels in real-world applications.
2017-03-28
Journal Article
2017-01-0342
Benjamin Möller, Alessio Tomasella, Rainer Wagener, Tobias Melz
In case of highly loaded welded structures, the fatigue strength of critical sections is dominated by plastic strains in the low cycle fatigue (LCF) regime. Regarding fatigue, the transition from the weld seam to the base material, which additionally is affected by the heat input due to welding, is the most critical region. Fatigue life assessment by the notch strain concept is based on the evaluation of the local strain at the weld toe or weld root and includes the cyclic material behavior. The choice of the stress-strain relation is connected to the cyclic stress-strain curve and a hardening model. Stress-controlled fatigue test results of butt joints and transverse attachments show a linear extension (in the log-log scale) of the S-N line into the LCF regime. Therefore, the nominal and notch stress concept can be applied up to at least 5,000 cycles to failure.
2017-03-28
Journal Article
2017-01-0625
Yen-Chung Liu, Brian Sangeorzan, Alex Alkidas
The purpose of this research was to measure and correlate the area-average heat transfer coefficients for free, circular upward-impinging oil-jets onto two automotive pistons having different undercrown shapes and different diameters. For the piston heat transfer studies, two empirical area-average Nusselt number correlations were developed. One was based on the whole piston undercrown surface area with the Nusselt number based on the nozzle diameter, and the other was based on the oil-jet impingement area with the Nusselt number based on the oil-jet effective impingement diameter. The correlations can predict the 95% and 94% of the experimental measurements within 30% error, respectively. The first correlation is simpler to use and can be employed for cases in which the oil jet wets the whole piston undercrown. The latter may be more useful for larger pistons or higher Prandtl number conditions in which the oil jet wets only a portion of the undercrown.
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
2017-01-0233
Weihong Guo, Shenghan Guo, Hui Wang, Xiao Yu, Annette Januszczak, Saumuy Suriano
The wide applications of automatic sensing devices and data acquisition systems in automotive manufacturing have resulted in a data-rich environment, which demands new data mining methodologies for effective data fusion and information integration to support decision-making. This paper presents a new methodology for developing a diagnostic system using manufacturing system data for high-value assets in automotive manufacturing. The key issues studied in this paper include optimal feature extraction using descriptive analysis, optimal feature subset selection using statistical hypothesis testing, machine fault prediction using multivariate process control chart, and diagnostic performance assessment using process trend detection. The performance of the developed diagnostic system can be continuously improved as the knowledge of machine faults is automatically accumulated during production.
2017-03-28
Journal Article
2017-01-1271
David Wright, John Henshaw, Nia R. Harrison, S. George Luckey
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
2017-01-1705
Hua-Chu Shih, Dajun Zhou, Bruce Konopinski
The hole piercing 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 lately 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 pieced hole can be critical due to their relatively lower edge stretching limits than those for the conventional low and medium strength steels. The stretchability of the as-sheared edge inside the hole can be influenced by the material property, die condition and processing parameters.
2017-03-28
Journal Article
2017-01-1707
C. Matthew Enloe, Jeff Wang, Jason Coryell
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 steels following similar pre-straining in uniaxial tension.
2017-03-28
Journal Article
2017-01-1642
Don Price
Each of the 300 (or more) electrical connectors in a vehicle is assembled by hand. Since there is a risk of a repetitive stress injury resulting from any of these connectors, significant work has been done to determine what test needs to be performed to determine whether a connector is ergonomically safe for the person performing the assembly operation. This prior work has determined the maximum force that can be safely applied to mate a connector... what is not known is whether the mate force of a connector is influenced by the assembly speed on connector. This has significant practical interest since the preferred lab-based test speed is 50mm/min., which is ten times slower than the typical assembly speed in a vehicle assembly plant. There have been some calls for a change in the current testing method to use speeds that match typical assembly speeds.
2017-03-28
Journal Article
2017-01-0126
Joshua W. Finn, John R. Wagner
Abstract 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, etc) 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
2017-01-0400
Theo Rickert
Abstract Hole drilling is a very common technique for measuring residual stresses. Adding an orbiting motion of the drill was found to improve hole quality in difficult to drill materials and has been in practice for decades. This study compares measurements using various orbiting amounts. Each measurement was repeated twice to evaluate measurement statistics. There is a distinct, though relatively small, effect of the hole shape when no orbiting is used. It disappears already when the hole is 50% larger than the tool size. Different orbiting amounts also produce systematically different results. These may be related to the absolute hole size.
2017-03-28
Journal Article
2017-01-1201
Zhenli Zhang, Zhihong Jin, Perry Wyatt
Abstract 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 plated lithium. We have studied the effects of charging pulses on homogenous plating in order to provide guidance for lithium ion battery design in hybrid applications.
2017-03-28
Journal Article
2017-01-0266
Shervin Shoai Naini, Junkui (Allen) Huang, Richard Miller, John R. Wagner, Denise Rizzo, Scott Shurin, Katherine Sebeck
Designing an efficient cooling system with low power consumption is of high interest in the automotive engineering community. Heat generated due to the propulsion system and the on-board electronics in ground vehicles must be dissipated to avoid peak component heat loads. In addition, proper thermal management will offer improved system durability and efficiency while providing a flexible, modular, and reduced weight structure. Traditional cooling systems are effective but they typically require high energy consumption which provides motivation for a paradigm shift. This study will examine the integration of passive heat rejection pathways in ground vehicle cooling systems using a thermal bus. Potential solutions include heat pipes and composite fibers with high thermal properties and light weight properties to move heat from the source to ambient surroundings.
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
2017-01-0452
David A. Stephenson
Abstract Thermally sprayed engine bores require surface preparation prior to coating to ensure adequate adhesion. Mechanical roughening methods produce repeatable surfaces with high adhesion strength and are attractive for high volume production. The currently available mechanical roughening methods are finish boring based processes which 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. This method uses two tools: a peripheral milling tool, which cuts a series of concentric grooves in the bore wall through interpolation, and a second rotary tool which deforms the grooves to produce an undercut. This method produces equivalent or higher bond strength than current surface preparation methods, and does not require diameter-specific tooling or bottom clearance for tool retraction.
2017-03-28
Technical Paper
2017-01-1074
Xingfu Chen, Todd Brewer, Cagri Sever, Eben Prabhu, Reda Adimi, Carlos Engler-Pinto
Abstract Cylinder head design is a highly challenging task for modern engines, especially for the proliferation of boosted, gasoline direct injection engines (branded EcoBoost® engines by Ford Motor Company). The high power density of these engines results in higher cylinder firing pressures and higher operating temperatures throughout the engine. In addition to the high operating stresses, cylinder heads are normally heat treated to optimize their mechanical properties; residual stresses are generated during heat treatment, which can be detrimental for high-cycle fatigue performance. In this paper, a complete cylinder head high cycle fatigue CAE analysis procedure is demonstrated. First, the heat treatment process is simulated. The transient temperature histories during the quenching process are used to calculate the distribution of the residual stresses, followed by machining simulation, which results in a redistribution of stress.
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.
2017-02-23
WIP Standard
AMS4959G
This specification covers a titanium alloy in the form of cold drawn wire.
CURRENT
2017-02-22
Standard
AMS4959F
This specification covers a titanium alloy in the form of cold drawn wire.
2017-02-22
WIP Standard
AS478P

This standard provides the following:

a. Definition of terms pertaining to marking.

b. Symbols for marking location.

c. Requirements and restrictions for permanent markings

d. Types of marking methods.

e. Rules for designating marking methods.

f. Table listing marking methods.

CURRENT
2017-02-21
Standard
AS6023
The scope of this document is to: • Provide a requirements document for RFID Tag Manufacturers to produce active RFID tags for the Aerospace industry. • Provide a requirements document for RFID Tag Manufacturers to produce active RFID tags for the Aerospace industry.Identify the minimum performance requirements for active RFID tags to be used on or in close proximity to aircraft. • Provide a requirements document for RFID Tag Manufacturers to produce active RFID tags for the Aerospace industry.Specify the test requirements specific to active RFID tags for aircraft use, in addition to RTCA DO-160 compliance requirements separately called out in this document. • Provide a requirements document for RFID Tag Manufacturers to produce active RFID tags for the Aerospace industry.Identify existing standards applicable to active RFID Tag. • Provide a requirements document for RFID Tag Manufacturers to produce active RFID tags for the Aerospace industry.Provide a certification standard for RFID tags which will use permanently-affixed installation on aircraft and aircraft parts. • Provide a requirements document for RFID Tag Manufacturers to produce active RFID tags for the Aerospace industry.Battery standards are separately captured and not included in this document.
2017-02-20
Article
Researchers from Purdue University are studying the fundamental mechanisms behind a method that uses electrical fields to enhance ceramics-sintering processing, which could aid R&D of rechargeable lithium-ion batteries and fuel cells. The research also could shed light on a phenomenon called electromigration, which can affect the performance of electronic devices.
2017-02-20
WIP Standard
AS6414A
This specification is applicable to the processes that are used in the manufacture of aerospace elastomer parts utilizing materials conforming to AMS7XXX series specifications, user specifications, or print on a Purchase Order (PO) that calls out this document for aerospace applications. The elastomer parts are in the form of O-rings, plate seals and other compression seals.
CURRENT
2017-02-17
Standard
AMSQQA225/4A
This specification covers the specific requirements for 2014 aluminum alloy bar, rod, wire and special shapes produced by rolling, drawing or cold finishing.
2017-02-16
WIP Standard
AMS2745B
This specification defines the requirements for locally hardening steel parts by the induction hardening method.
2017-02-16
WIP Standard
AMS4485A
This specification covers a magnesium alloy in the form of extruded bars, rods, wire, tubing, and profiles. These extrusions have been used typically for parts requiring a combination of light weight, high yield strength up to 480 °F (250 °C), relatively high corrosion resistance, and good flammability resistance for magnesium alloys,but usage is not limited to such applications.
CURRENT
2017-02-15
Standard
AMS5047G
This specification covers an aluminum-killed carbon steel in the form of sheet and strip.
2017-02-14
Article
The high cost of developing new technologies such as fuel cells is making partners out of competitors.
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