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Viewing 1 to 30 of 21019
2017-03-28
Technical Paper
2017-01-1704
D.J. Branagan, A.E. Frerichs, B.E. Meacham, S. Cheng, A.V. Sergueeva
Demand is growing for advanced high strength steels (AHSS) in the automotive industry driven by a desire for lightweighting solutions to meet increasingly stringent fuel economy standards. Formability is a critical factor for producing reduced gauge steel parts with the complex geometries required to maintain stiffness. 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. Numerous correlations have been previously developed to predict local formability such as yield strength to tensile ratio, true strain at fracture, and post uniform elongation but they are often inaccurate – particularly for AHSS grades.
2017-03-28
Technical Paper
2017-01-0301
Lu Huang, Ming Shi
Forming limit curve (FLC) is a useful tool to characterize the formability of sheet metals. It can be used as a failure criterion in a laboratory setting or computer simulation for forming/stamping studies and in actual production in a press shop to assess the formability severity. Digital image correlation (DIC) technique has been proved as a potent tool to determine the FLC of sheet metals. Despite of its rising popularity, one of the major technical challenges using the DIC to generate FLC is to accurately pinpoint the onset of localized necking based on DIC data analysis. In addition to the commonly applied ISO 12004-2 standard, a plethora of DIC data analysis approaches have been developed. In this study, five different approaches have been practiced to determine the limit strains at the onset of localized necking, including: ISO12004-2 standard, second derivative, gliding correlation coefficient, linear best fit, and curvature assisted necking zone methods.
2017-03-28
Technical Paper
2017-01-0305
Liang Huang, Charles Yuan
This paper focus on the design approach of mapping the equivalent bead to the physical bead geometry. In principle, the physical character and geometry of equivalent bead is represented as restraining force (N/mm) and a line (bead center line). During draw development, the iterations are performed to conclude the combination of restraining force that obtains the desired strain state of a given panel. The objective of physical bead design to determine a bead geometry that has the capacity to generate the same force as specified in 2D plane strain condition. The software package ABAQUS/CAE/iSight is utilized as primary tool. In the approach, the bead geometry is sketched and parameterized in ABAQUS/CAE and optimized with iSight to finalize the bead geometry. This paper also discuss the special consideration of lock bead design.
2017-03-28
Technical Paper
2017-01-0311
Pedro Stemler, Anoop Samant, Dennis Hofmann, Taylan Altan
The capabilities of the servo press for varying the ram speed during stroke and for adjusting the stroke length are well known. Also during the blanking operation, the servo can help to slow down the press at the critical moment of blanking without losing overall productivity. The overall objective of this study is to determine, for a selected sheet material and hole diameter, the servo press motion that possibly could provide the “Best” possible blanked/sheared edge quality to improve the Hole Expansion Ratio (HER) in hole flanging. The specific objectives are to determine the effect of ram (blanking) speed upon the edge quality, and the effect of multiple step blanking (as much as possible with the servo press available) using several punch motions, during one blanking stroke. The material used in these studies was 1.4 mm thick 780 MPa TRIP steel and the blanked hole had a diameter of 75 mm.
2017-03-28
Technical Paper
2017-01-1665
Qigui Wang, Peggy Jones, Yucong Wang, Dale Gerard
With the increasing use of aluminum shape castings in structural applications in the automotive and aerospace industries, 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. 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 Integrated Computational Materials Engineering (ICME) approach is also discussed.
2017-03-28
Technical Paper
2017-01-1274
Jason M. Luk, Hyung Chul Kim, Robert De Kleine, Timothy J. Wallington, Heather L. MacLean
This study investigates the life cycle greenhouse gas (GHG) emissions of a set of vehicles using two real-world gliders (vehicles without powertrains or batteries); a steel-intensive 2013 Ford Fusion glider and a multi material lightweight vehicle (MMLV) glider that utilizes significantly more aluminum and carbon fiber. These gliders are used to develop lightweight and conventional models of internal combustion engine vehicles (ICV), hybrid electric vehicles (HEV), and battery electric vehicles (BEV). Our results show that the MMLV glider can reduce life cycle GHG emissions despite its use of lightweight materials, which can be carbon intensive to produce, because the glider enables a decrease in fuel (production and use) cycle emissions. However, the fuel savings, and thus life cycle GHG emission reductions, differ substantially depending on powertrain type. Compared to ICVs, the high efficiency of HEVs decreases the potential fuel savings.
2017-03-28
Technical Paper
2017-01-0314
Lu Huang, Ming Shi, Patrick Russell
Fracture strain data provide essential information for material selection and serve as an important failure criterion in the computer simulations of crash events. Traditionally, the fracture strain was measured by evaluating the thinning at fracture using tools such as microscopes or a point micrometer. In the recent decades, digital image correlation (DIC) has evolved as a state-of-the-art optical system to record full-field strain history of materials. Using this method, a complete set of the fracture strains (including major, minor, and thinning strains) can be approximated for the material with the recorded data prior to a visible crack. However, results directly obtained with DIC can be dependent on experimental setup and evaluation parameters, which potentially introduce errors to the reported results.
2017-03-28
Technical Paper
2017-01-0487
Daisuke Hyodo, Kiyohiro Suzuki, Toshiyuki Tsutsumi, Kuriyama Hideki
Rubber gaskets, for example O-rings, and rubber valves achieve their sealing performances when compressed rubber material fills in the gap between the gasket and the counter surface and a continuous contact is formed between them. Leaking is likely to occur at low temperature since it is difficult for the rubber gasket to deform along the roughness of counter surface because of decreasing in rubber elasticity. However, sticking to the counter surface prevents the gasket from ease removing from it due to sealing pressure and sealing fluid from leaking through the gap. It is considered that sticking affects sealing property of rubber gaskets at low temperature. Therefore we studied effects of rubber material, roughness of counter surface and temperature sequence on sealing property by measuring sticking force and observing contact area. The sealing property depended on sticking force at low temperature and enhancement of sticking force enabled to seal at higher pressure.
2017-03-28
Technical Paper
2017-01-0254
Sudeep Chavare, Kevin Thomson, Nitin Sharma
Adopting parametric approach to optimize CAE models for various objectives is a common practice these days. Connection entities such as welds and adhesive play a very important role in overall performance matrix and hence adding them to the pool of design variables during an optimization exercise provides additional design space. This paper evaluates the possibility to use structural adhesives as patches rather than continuous lines. The method presented in this paper offers unique approach to parameterize adhesive lines. The paper discusses an optimization study with structural adhesives patches along with spot weld pitch as design variables. Body in White (BiW) and Trimmed Body in White (TBiW) models are used for analysis .The goal of the study is to reduce total length of structural adhesive as well as number of welds while maintaining baseline NVH performance as constraints.
2017-03-28
Technical Paper
2017-01-0227
Omar Al-Shebeeb, Bhaskaran Gopalakrishnan
Process planning, whether generative or variant, can be used effectively as through the incorporation of computer aided tools that enhance the evaluator impact of the dialogue between the design and manufacturing functions. Expert systems and algorithms are inherently incorporated into the software tools used herein. This paper examines the materials related implications that influence design for manufacturing issues. Generative process planning software tools are utilized to analyze the sensitivity of the effectiveness of the process plans with respect to changing attributes of material properties. The shift that occurs with respect to cost and production rates of process plans with respect to variations in specific material properties are explored. The research will be analyzing the effect of changes in material properties with respect to the design of a specific product that is prismatic and is produced exclusively by machining processes.
2017-03-28
Technical Paper
2017-01-0295
Silvio César Bastos
Automotive industries has been seeking quality excellence as a key factor of competitiveness. Product characteristics and functions should meet the expectations of customers in terms of warranty and reliability. The objective of this paper is to present a method to improve the synchronization of customer´s products requirements with their suppliers in terms of key performance indicators. The improvement allows suppliers to take corrective and preventive actions through knowledge of components application in engines and vehicles. Engines assembly lines maintain records and daily meeting to explore trends of productivity and supplier quality performance is measured based on engines failure instead parts supplied. This methodology results integration between Lean Manufacturing and Supplier Quality Engineering and respective targets communizing efforts toward Quality Assurance.
2017-03-28
Technical Paper
2017-01-1706
Sandeep Bhattacharya, Daniel Green, Raj Sohmshetty, Ahmet Alpas
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
2017-01-0308
Hyunok Kim, Jianhui Shang, James Dykeman, Anoop Samant, Clifford Hoschouer
Practical evaluation and accurate prediction of edge cracking are very 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 and used to obtain consistent sheared-edge quality. 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 (i.e. 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
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 a necessity prior to production. New time dependent methods using digital imaging correlation (DIC) account for variations in deformation 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
Technical Paper
2017-01-0394
Junrui Li, Ruiyan Yang, Zhen Li, Changqing Du, Dajun Zhou, Lianxiang Yang
Advanced high-strength steel (AHSS) is gaining popularity in the automotive industry due to its higher final part strength with the better formability compares to the conventional steel. However, the edge fracture occurs during the forming procedure for the pre-strained part. To avoid the edge fracture happens during the manufacturing, the effect of pre-strain on edge cracking limit need to be studied. In this paper, digital image correlation (DIC), as a high accuracy optical method, is adopted in the strain measurement for the edge cracking limit determination. Sets of the wide coupons are pre-strained to obtain the samples at different pre-strain level. The pre-strain of each sample is precisely measured during this procedure using DIC. After pre-straining, the half dog bone samples are cut from these wide coupons. The edge of the notch in the half dog bone samples is created by different methods for the distinct edge condition.
2017-03-28
Technical Paper
2017-01-0231
Shih-Po Lin, Yijung Chen, Danielle Zeng, Xuming Su
In the conventional approach, the material properties of laminate composites for crash simulations are typically obtained from standard coupon tests, where the test results only provide single layer material properties. However, the lay-up effects for the failure behaviors of the real structure were not considered in numerical simulations. Hence, there was discrepancy between the crash simulations and experimental tests. Consequently, an intermediate stage is required for accurate predictions. Some component tests are required to calibrate the material models in the intermediate stage. In this paper, a laminate cylinder tube under high-impact velocity in the direction of tube axis is chosen as an example for the crash analysis. The tube consists of 24 layers of uni-directional (UD) carbon fiber composite materials, in which 4 layers are perpendicular to, while the other layers are parallel to the impact direction.
2017-03-28
Technical Paper
2017-01-1372
Bo Wang, Smruti Panigrahi, Mayur Narsude, Amit Mohanty
Increasing numbers of vehicles are equipped with telematics devices and they are able to transmit vehicle CAN bus information remotely. We examine the possibility of identifying individual drivers from their on-road driving behaviors. This study collected vehicle telematics data from a small fleet of Ford Fiesta vehicles over 6 months in London, UK. The collected variables included vehicle speed, acceleration pedal position, brake pedal pressure, steering angle position, gear position, and engine RPM. A list of driving metrics were developed to quantify driver behaviors, such as mean brake pedal pressure and turning speed. The Random Forest (RF) machine learning algorithm is used to predict driver IDs based on the developed driving metrics. The RF model is also used to rank the importance of each driving metric on driver identification. In conclusion, this paper demonstrates the possibility of identifying drivers from their on-road driving behaviors.
2017-03-28
Technical Paper
2017-01-1275
David Hobbs, Charles Ossenkop, Andy Latham
Global sales of electric and hybrid vehicles continue to grow as emission legislation forces vehicle manufacturers to build cleaner vehicles, with some 8 million already in service. Hybrid and Electric vehicles contain some of the most complex systems ever used in the automotive field, sophisticated and unique electric hybrid systems are added to modern motor vehicles which re already quite complex. As these vehicles reach the end of their lives they will be processed by the global vehicle recycling industry and the high voltage components will be reused, recycled or re-purposed. This paper explores safe working practices for businesses involved in a global marketplace who are completing battery disabling, removal, disassembly, storage and shipping; includes the various technologies and safe working practices along with some of the legal restrictions on dismantling, storage and shipping of high voltage batteries around the world.
2017-03-28
Technical Paper
2017-01-1239
Naoya Take, Takuya Kadoguchi, Masao Noguchi, Kimihiro Yamanaka
Power modules are used to operate three-phase alternative motors in hybrid vehicles and electric vehicles. The good fuel efficiency and high power density are requested in the field of hybrid vehicles. To achieve this goal, the miniaturization of power module will be necessary. This trend may make current density, which is operated by insulated gate bipolar transistors (IGBTs) and Free wheel diodes (FWDs), higher in power modules. Solder is often used as the joint material of power modules. It is known that a current density larger than 10 kA/cm2 causes solder electromigration which exchanges momentum from electrons to metallic atoms .This phenomenon may cause delamination of the joint area and void formation. In addition, the ambient temperature has an influence on electromigration. The temperature of an engine compartment is high, so it is likely to cause electromigration.
2017-03-28
Technical Paper
2017-01-1074
Xingfu Chen, Todd Brewer, Cagri Sever, Eben Prabhu, Reda Adimi, Carlos Engler-Pinto
Cylinder head design is a highly challenging task for modern engines, especially for the proliferation of boosted engines (branded EcoBoost® engines by Ford Motor Company). The higher power density of these engines results in higher cylinder pressures and higher operating temperatures throughout the engine. In addition to the operating conditions, cylinder heads are usually heat treated to optimize its mechanical properties; residual stresses are generated during heat treatment, which could 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 redistributes the stress.
2017-03-28
Technical Paper
2017-01-0226
Vesna Savic, Louis Hector, Ushnish Basu, Anirban Basudhar, Imtiaz Gandikota, Nielen Stander, Taejoon Park, Farhang Pourboghrat, Kyoo Sil Choi, Xin Sun, Jun Hu, Fadi Abu-Farha, Sharvan Kumar
This paper presents the development of a multi-scale material model for a 980MPa grade transformation induced plasticity (TRIP) steel, subject to a two-step quenching and partitioning heat treatment (QP980), based on integrated computational materials engineering (ICME) principles. The model combines micro-scale material properties defined by the crystal plasticity theory with the macro-scale mechanical properties, such as flow curves under different loading paths. For an initial microstructure, the flow curves of each of the constituent phases (ferrite, austenite, martensite) are computed based on the crystal plasticity theory and crystal orientation with input parameters calibrated by micropillar experiments. Crystal plasticity predicted phase properties are then used as inputs to a state variable model which computes macro-scale flow curves while accounting for hardening caused by austenite transformation into martensite under different straining paths.
2017-03-28
Technical Paper
2017-01-0286
Amrinder Singh, Abhishek Ramakrishnan, Guru Dinda
Additive manufacturing (AM) of metals is finding numerous applications in automotive industry. In 21st century aluminum is second to steel in automotive sector, because of its high strength to weight ratio and hence developing AM for aluminum alloys becomes necessary to make sure industry gains maximum benefit from AM. This study specifically deals with the manufacturing of Al 7050 alloy, which is quite hardest alloy to manufacture using AM. The ultimate goal is to optimize the laser deposition parameters to deposit defect free Al 7050 alloy on rolled aluminum alloy substrate. Parameter optimization (laser power, powder flow rate and scanning speed) gets difficult with the presence of various low melting and boiling point alloying elements such as Zn, Mg etc. Numerous other challenges faced while depositing Al 7050 alloy, are also being briefly discussed in this article.
2017-03-28
Technical Paper
2017-01-0183
Mingyu Wang, Timothy Craig, Edward Wolfe, Tim J LaClair, Zhiming Gao, Michael Levin, Danrich Demitroff, Furqan Shaikh
Without the waste heat available from the engine of a conventional automobile, electric vehicles (EVs) must provide heat to the cabin for climate control using energy stored in the vehicle. In current EV designs, this energy is typically provided by electrical energy from the traction battery. In very cold climatic conditions, the driving range of an EV can be reduced by 50% or more. To minimize this EV range penalty, a novel thermal energy storage system has been designed to provide cabin heat in EVs and Plug-in Hybrid Electric Vehicles (PHEVs) using the stored latent heat from an advanced phase change material (PCM). This system is known as the Electrical PCM-based Thermal Heating System (ePATHS). When the EV is connected to the electric grid to charge its traction battery, the ePATHS system is also “charged” by melting the PCM. The stored thermal energy is subsequently deployed for cabin heating during driving.
2017-03-28
Technical Paper
2017-01-1323
Jerry Lai, Youssef Ziada, Juhchin Yang
In the assembly of axle and wheel hub, a nut is frequently used to fasten the two components. In order to retain the nut in final position to hold the axle assembly, crimping is a widely-used method to prevent nut from loosening. A reliable crimping process not only prevents the movement of nut during axle operation but also minimizes the possibility of cracking the rim. Nut can start to rust and deteriorate if crack exists. Service life span of the axle assembly hence shortened 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.
2017-03-28
Technical Paper
2017-01-0351
Guofei Chen, Mingchao Guo
Advanced high strength steels (AHSS) have been extensively used in the automotive industry for vehicle weight reduction. Although AHSS show better parental metal fatigue performance, the influence of material strength on spot weld fatigue is insignificant. To overcome this drawback, structural adhesive was used along with spot weld to form weld-bond joints, which greatly improved spot weld fatigue performance and joint stiffness of the downgaged AHSS structures. In this study, the formulation of cohesive element based on Cohesive Zone Model (CZM) was employed to predict the onset and propagation of failure in the adhesively bonded joints in lap-shear and coach-peel specimens under quasi-static loadings. The predicted responses were compared with experimental results with good agreement.
2017-03-28
Technical Paper
2017-01-0300
Hong Yao, Sriram Sadagopan, Min Kuo, Liang Huang, Evangelos Liasi
The risk of skid line marks for Class A panel has to be assessed before releasing the die development for hard tooling. A criterion is needed to predict skid line in formability evaluation process. In this study, a standard strip draw test procedure was developed to generate skid mark on lab samples for the physical evaluation using tooling with various die entry radii and different draw beads. The skid line severity of the lab samples was rated by specialist inspecting automotive outer panel surface quality. The skid line rating was correlated with geometric measurements of the lab sample after strip drawn. The sensitivity for appearance of skid line to tooling and process parameter variation was identified. Finite element simulation was conducted to correlate with test measurement to understand the reason of skid line mark and discover the critical conditions to have visible skid line. Results for strain variables were post processed and correlated with the skid line rating.
2017-03-28
Technical Paper
2017-01-1537
Ananya Bhardwaj
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 novel 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 modelled boundary conditions like moving ground to exactly replicate true conditions. It also quantifies the improvement in cooling rate of the brake disc with change in wheel design unlike previous studies. The axial flow discharge was found to be increased to 0.47 m3/min for the suggested design in comparison to 0.04 m3/min for traditional design.
2017-03-28
Technical Paper
2017-01-1666
David Weiss, Orlando Rios
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 400°C.
2017-03-28
Technical Paper
2017-01-0468
Raj S. Roychoudhury
Plastic hollow articles are used in automotive applications such as high pressure fluid bottles, active globe box knee airbags, etc. Welding of plastic hollow articles to create a pressure vessel is a challenge. The weakest points are usually the weld seam where the part tends to separate under internal pressure. The reason for the weakness is that the weld is configured as an L-shaped joint and the loading is in peel. The L-shaped weld joint is the result of the injection molding limitations such as die lock and also the welding process adopted with its perceived design limitations. A new weld design to form plastic hollow articles is conceived. Its design is T-shaped such that the joint loading under pressure is no longer in peel but in tension, vertically to the weld surface. This weld design can be easily achieved, overcoming the limitation of die lock in injection molding and by the hot plate weld design adopted for this welding.
2017-03-28
Technical Paper
2017-01-0338
Jeong Kyun Hong, Andrew Cox
Even under uniaxial loading, seemingly simple welded joint types can develop multi-axial stress states, which must be considered when evaluating both the fatigue strength and failure location. Two well established examples of this are a hollow tube through a flat plate and a flat plate with an angled attachment plate. The stress distribution at these weld failure locations show significant in-plane shear stress in addition to the usual normal stress. Previously the author noted that when only the normal structural stress is considered for these joints the predictions of both the fatigue failure location and the fatigue life using the master S-N curve approach are inaccurate because the in-plane shear stress plays a significant role in the development of the crack.
Viewing 1 to 30 of 21019

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