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Viewing 1 to 30 of 15892
2017-04-11
Journal Article
2017-01-9451
Marouen Hamdi, Drew Manica, Hung-Jue Sue
Abstract Brightness, transparency, and color impact critically the aesthetics of polymeric surfaces. They can significantly change the perception of common damages such as scratch and mar. Particularly, subtle mar damage is more dependent on surface perceptual properties. In this study, we investigate the impact of these attributes on scratch and mar visibility resistance of commercialized polymeric model systems frequently used in automotive industry. Twenty subjects were involved in a psychophysical test based on pairwise comparison, and results were treated using multidimensional scaling (MDS) analysis. A tied ordinal weighted Euclidian MDS model was used to visualize the relational structures of mar perception space. Results show that scratch visibility resistance tends to decrease with dark, more transparent, and green surfaces. Mar perception was reasonably conceptualized by a two-dimensional MDS space.
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
2017-01-1665
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
2017-01-0487
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
2017-01-1706
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
2017-01-1248
Ming Su, Chingchi Chen, Krishna Prasad Bhat, Jun Kikuchi, Shrivatsal Sharma, Thomas Lei
Due to global trends and government regulations for CO2 emission reduction, the automotive industry is actively working toward vehicle electrification to improve fuel efficiency and minimize tail-pipe pollutions. For the traction inverter systems in today’s hybrid electric vehicles (HEV), silicon IGBTs and power diodes are the main control devices. These mature components are reliable and cost-effective, but have their limitation on energy losses. SiC wide bandgap semiconductor, on the other hand, has potential to offer additional boost of efficiency for the HEV drive system. In recent years, commercial SiC MOSFETs are significantly improved in terms of conduction and switching losses. However, reliability concerns and high prices still place a limit on their overall competitiveness against silicon. Ford Motor Company has partnered with major semiconductor manufacturers to evaluate SiC products for the HEV inverter system.
2017-03-28
Technical Paper
2017-01-0363
Karthik Ramaswamy, Vinay L. Virupaksha, Jeanne Polan, Biswajit Tripathy
EPP foams are most commonly used in automotive applications for pedestrian protection and to meet low speed bumper regulatory requirements. In today’s automotive world the design of vehicles are predominantly driven by CAE. This makes it necessary to have validated material model for EPP foams in order to simulate and predict performance under various loading conditions. Since most of the automotive OEMs depend on local material suppliers for their global vehicle applications it is necessary to understand the variation in mechanical properties of the EPP foams and their effect on performance predictions. In this paper, EPP foams from three suppliers across global regions are characterized to study the inter-supplier variation in mechanical properties. In order to understand the effect of inter-supplier variation on vehicle performance, LSDYNA rate dependent material model is developed and validated for low speed and pedestrian protection load cases.
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
2017-01-0343
Xiao Wu, Zhigang Wei, HongTae Kang, Abolhassan Khosrovaneh
Over the decades, several attempts have been made to develop new fatigue analysis methods for welded joints since most of the incidents in automotive structures are joints related. Therefore, a reliable and effective fatigue damage parameter is needed to properly predict the failure location and fatigue life of these welded structures to reduce the hardware testing, time, and the associated cost. The nodal force-based structural stress approach is becoming widely used in fatigue life assessment of welded structures. In this paper, a new nodal force-based structural stress recovery procedure is proposed that uses the least squares method to linearly smooth the stresses in elements along the weld line. Weight function is introduced to give flexibility in choosing different weighting schemes between elements. Two typical weighting schemes are discussed and compared.
2017-03-28
Technical Paper
2017-01-0175
Jing He, Bill Johnston, Debasish Dhar, Loren Lohmeyer
The traditionally used refrigerant in mobile air conditioning (MAC), R134a, has a high GWP of 1,300 and is to be banned in EU market for new passenger cars and light commercial vehicles from January 1, 2017. In US, EPA has listed R134a as unacceptable for new light-duty vehicles beginning in Model Year 2021. The natural refrigerant, R744 (CO2), remains a viable solution to replace R134a due to its environmental friendliness, low cost, non-flammability, and high volumetric heat capacity. One challenge of R744 vapor compression system is reduced efficiency with ambient temperature. Prior research has demonstrated that a parallel or multistage compression cycle represents a superior design to a conventional single-compression cycle in that it not only improves the optimum cooling efficiency, but also brings down the optimum discharge pressure.
2017-03-28
Technical Paper
2017-01-1298
Kamlesh Yadav, Abhishek Sinha, Rajdeep Singh Khurana
Vehicle Hood being the face of a passenger car poses a challenge to meet the regulatory and aesthetic requirements. However, the urge to make a saleable product makes aesthetics a primary condition. This eventually makes the role of structure optimization much more important. A recent development in the Indian automotive industry, which is known for dynamics of cost competitive cars, has posed the challenge to make passenger cars meeting the regulation and having optimized cost. This work is application of structure optimization of Hood and design of peripheral parts for meeting pedestrian protection performance keeping the focus on having cost-effective solution. This paper discusses Headform compliance of the work done on one of the flagship model of Maruti Suzuki India Ltd., providing detailed analysis of the procedure followed from introduction stage of regulatory requirement in the project to final validation of the engineering intent.
2017-03-28
Technical Paper
2017-01-1645
Marjorie Myers
Harness and terminal manufacturers are working to support the Automotive industry’s need to reduce energy consumption (and costs) via weight savings initiatives by converting from Cu to Al electrical cables within the traditional open style cable harness termination manufacturing environment. As the Automotive industry is fully aware, terminating nominally same sized Al cable to existing Cu cable designed terminals is neither a functional, nor a reliable, equivalent option – termination design changes are required to be able successfully qualify any such Al cable to Cu terminal connections for Automotive applications. In addition, the harness industry are looking for any new Al ‘open’ crimp termination designs to work well within the existing manufacturing and connector/harness design environment; e.g., ‘open’ crimp termination, on par termination process speed, no post-treatment, etc.
2017-03-28
Technical Paper
2017-01-1300
Raj Jayachandran, Bhimaraddi Alavandi, Matt Niesluchowski, Erika Low, Yafang Miao, Yi Zhang
An engine cooling system in an automotive vehicle comprises of heat exchangers such as a radiator, charge air cooler, and oil coolers along with engine cooling fans. Typical automotive engine-cooling fan assembly includes an electric motor mounted on to a shroud that encloses radiator core. Typically a fan shroud is made of plastic material and holds one or two motors and is supported at four corners. One of the main drivers of a fan shroud design is Noise, Vibration, and Harshness requirements, without compromising the main function - airflow requirement for cooling. Usually, stiffness requirement is not given adequate attention in arriving at optimal design of a fan shroud. Research Council for Automotive Repairs (RCAR), based in Europe, issues vehicle ratings on the basis of its performance in Low Speed Damageability (LSD) tests. One such test is a 15kph, 40% offset rigid wall impact to the front of the vehicle.
2017-03-28
Technical Paper
2017-01-0357
Dattaprasad Lomate, Asim Tewari, Prashant Date, Manoj R Ukhande, Girish M Shegavi, Raj Kumar Prasad Singh
The application of induction hardening treatment plays a vital role for enhancing fatigue life of various automotive components. This will incorporate compressive residual stresses in the component at significant extent. In this paper, wide range of experiments have been carried out on Rotating Bending Fatigue (RBF) specimens made from 38MnVS6 micro alloyed steel with induction hardening up to three different case depths. The set of specimens are fatigue tested at fully reverse loading condition using rotating bending fatigue testing machine. Based on this study a surface treatment factor is evaluated. This surface treatment factor is used as an input for evaluating precise fatigue life of the specimen using FEA packages. The fatigue life evaluated using FEA is showing good agreement with the results obtained through tests on the actual specimens.
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
2017-01-0172
Suhas Venkatappa, Manfred Koberstein, Zhengyu Liu
Due to regulations related to global warming, the auto industry is transitioning to the use of a new refrigerant R1234yf in many markets/regions. This transition to the new refrigerant was considered to be a minor development effort with main focus on improved sealing, improving cooling capacity with adding content such as Internal Heat Exchanger (IHX) to recoup the lower cooling efficiency of R1234yf compared to R134a. There were no redesigns of major refrigerant system components expected with the introduction of R1234yf. The actual implementation of this refrigerant has proven to be more challenging due to several NVH issues. Some of the challenges related to NVH are driven by the differences in refrigerant characteristics – mass flow rate, velocity of sound in refrigerant.
2017-03-28
Technical Paper
2017-01-1230
Cyrille Goldstein, Joel Hetrick
Mechanical losses in electric machines can contribute significantly to overall system losses in an electric drive. With an Interior Permanent Magnet (IPM) machine, measuring mechanical losses is difficult without an un-magnetized rotor. Even with an un-magnetized rotor, physical testing can be time consuming and expensive. This paper presents a theoretical model of mechanical drag in an electric machine. The model was built using calculations for bearing, seal, and windage drag. This model was compared to experimental results and a sensitivity study was completed to understand inaccuracies in the model. Based on this information, the model was modified to better represent the physical system. The goal of this work is to understand the contributors to mechanical drag, to be able to estimate mechanical losses without physical testing, and to evaluate design choices that could reduce mechanical losses.
2017-03-28
Technical Paper
2017-01-0125
Marco Pizzi, Mauro Zorzetto, Alberto Barbano, Piercarlo Merlano, Luca Vercellotti
The reduction of emissions in gasoline and diesel engines is driving the introduction of systems implementing additives in liquid form: in particular water for injection systems in gasoline engines and urea solutions (AD-blue) in SCR systems in diesel engines. Unfortunately water and AD-Blue can freeze in the car operative temperature range. In both cases the tanks must be equipped with heaters to guarantee a sufficient amount of additives in liquid form. Currently used technologies are ceramic PTC elements and distributed metal resistors. Ceramic PTC based heaters concentrate all the power in small volumes. They need thermally conductive elements distributing the power over a wide area. The assembly is complex and the cost of the metal parts and related packaging technologies used to insulate the heater from the environment (water or urea) is typically high. Metal resistors are cheaper but must be controlled in current.
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
2017-01-0345
SungChul Cha, Seung-Hyun Hong, Shahriar Sharifimehr
Fatigue behavior of two types of automotive steel, quenched and tempered SUJ2 and carburized SCM820PRH, which are applied as powertrain parts are studied. These two types of steel are different in their hardness distribution from surface to core. The hardness of quenched and tempered SUJ2 is homogeneous, in contrast to that of carburized SCM820PRH (SCM) which decreases from surface to core. These steels are investigated in terms of their monotonic tensile properties and fatigue behavior. A number of predictive methods were used to describe the fatigue behavior of these steels. A simple predictive method is based on approximation of S-N curve from ultimate tensile strength. The well known Murakami’s defect area method was also applied for the prediction of the high cycle fatigue strength.
2017-03-28
Technical Paper
2017-01-0376
Jianyong Liang, Jonathan Powers, Scott Stevens, Behrooz Shahidi
While Advanced High Strength Steels (AHSS) and next generation steel grades offer improved crash safety and reduced weight for vehicles, the global stiffness and NVH performance are often compromised due to reduced material thickness. This paper discusses an advanced method of evaluating the joint effectiveness on contribution to global stiffness and NVH performance of vehicles. A stiffness contribution ratio is proposed initiatively in this research, which evaluates the current contribution of the joints to the global stiffness and NVH performance of vehicles. Another parameter, joint effectiveness factor, has been used by Ford Motor Company to study the potential of each joint on enhancing the global stiffness. The critical joints to enhance the vehicle stiffness and NVH performance can be identified based on above two parameters, and design changes be made to those critical joints to improve the vehicle performance.
2017-03-28
Technical Paper
2017-01-1303
Nobuhisa Yasuda, Shinichi Nishizawa, Maiko Ikeda, Tadashi Sakai
The purpose of this study is to validate a reverse engineering based design method for automotive trunk lid torsion bars (TLTB) in order to determine a free shape that meets a target closed shape as well as a specified torque. A TLTB is a trunk lid component that uses torsional restoring force to facilitate the lifting open of a trunk lid, as well as to maintain the open position. Bend points and torque at a closed trunk position are specified by a car maker. Conventionally, a TLTB supplier determines bend points of the free shape by rotating the given bend points from a closed position around a certain axis to satisfy the specified torque at the closed position. Bend points of a deformed TLTB shape in the closed position often do not match the target bend points given by a car maker when designed by the conventional method, which can potentially cause interference issues with surrounding components.
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
2017-01-1220
Ahmad Arshan Khan
In an electrified vehicle, magnet temperature plays a critical role in determining optimal current control trajectory of an interior permanent magnet machine. Monitoring magnet temperature is a challenging task. In lab and various specialized applications, infrared sensors or thermocouples are used to measure the temperature. But it adds cost, maintenance issues and their integration to electric machine drives could be complicated. To tackle the issues due to sensor based methods, various sensor-less model based approaches are proposed in the literature recently such as flux observer, high-frequency signal injection, and thermal models, etc. Although magnet temperature monitoring received a lot of attention of researchers, very few papers give a detailed overview of the effects of magnet temperature on motor control from a controls perspective. In this paper, we will show the effect of the change in magnet temperature on Maximum Torque per Ampere control and Flux Weakening Control.
2017-03-28
Technical Paper
2017-01-1234
Srikanthan Sridharan, Joseph Kimmel, Jun Kikuchi
Dc-link capacitor sizing considerations are discussed for HEV/EV e-Drive systems. The capacitance value of the dc-link in HEV/EV e-Drive systems affects numerous factors. For example, some of the most significant are the system stability and the maximum tolerable dc-bus transient voltage with operating point change or with worst-case energy dump into the capacitor. Also to be paid attention is the equivalent series resistance and inductance of the capacitor module, because they affect thermal behavior of the capacitor module and voltage spikes occurring across a power semiconductor switch with its every turning-off instant, respectively. In addition, these factors are cross-coupled with other power-stage component parameters, control structures and controller gains. Furthermore such effects and cross-couplings are operating point dependent.
2017-03-28
Technical Paper
2017-01-0371
Raju Gandikota, Amit Nair, Kurt Miller
Testing elastomeric materials that undergo large strains pose challenges especially when establishing failure criteria. The failure criterion for composites and polymers based on finite elasticity published byFeng (1) requires testing under uni-axial and bi-axial stretching modes. The classic inflation of a circular disk for bi-axial stretch mode poses stability and safety challenges. The test can also be sensitive to end constraints resulting in failure of materials at the constraints. Bi-axial stretching with a hemispherical punch is explored in this work. The bi-axial stretching allows controlled and repeatabletesting. It establishes clear and reliable failure mechanism of the material at the poles. Through a combination of testing and numerical methods, the stretch ratios and its relation to failure has been established.
Viewing 1 to 30 of 15892