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Viewing 91 to 120 of 20990
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
2017-01-0229
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
Technical Paper
2017-01-0396
Guobiao Yang, Changqing Du, Dajun Zhou, Hao Wang, Elizabeth Lekarczyk, Lianxiang Yang
As we know, the lighting car is very important for automotive industry in recent years. There are lot of components which could be lighted weight in one vehicles. In modern automotive field Aluminum alloy widely has been used to formed into parts of vehicles, because it has very good ideal properties for the stamping process which need material both malleable and ductile. During vehicles manufacture process, lots of aluminum alloy has been stamped into parts of components. It is very important for engineer to know how to predict the fracture of aluminum alloy, in order to simulate stamping process in automotive field by FEM. This research presents strains distribution of A5182 aluminum during sample being impacted with punch heads under loading. DIC has been used technically to measure the whole history strain when sheet sample has been impacted, and the shape of sheet sample also has been tested in order to obtain the aluminum sheet springback(side-wall-curl).
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
2017-01-0313
Praveen Balaj Balakrishnan, Girish Kumar Rajendiran, Ravi Purnoo Munuswamy
In recent years the need of having parts with high strength with low weight has grown exponentially and automotive industry has relied heavily on hot stamping technology to achieve this. Hot stamped parts can provide high strength and very good shape fixability for reduced weight compared to cold formed parts. This paper does a detail investigation Boron steel 22MnB5 and the different thermal parameters such as quenching rate, forming temperature, and quenching force that governs the phase transformation of the material, which in turn will decide the components’ strength and hardness. The paper also will investigate the role of part geometry in phase transformation. Optimizing the above mentioned parameters to achieve a minimum manufacturing time per part is one of the objectives of this paper.
2017-03-28
Technical Paper
2017-01-1513
Young-Chang Cho, Chinwei 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
Technical Paper
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
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
2017-01-0230
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
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.
2017-03-28
Technical Paper
2017-01-1663
Alan Druschitz, Christopher Williams, Erin Connelly, Bob Wood
Binder jetting of sand molds and cores for metal casting provides a scalable and efficient means of producing metal components with complex geometric features made possible only by Additive Manufacturing. Topology optimization software that can mathematically determine the optimum placement of material for a given set of design requirements has been available for quite some time. However, the optimized designs are often not manufacturable using standard metal casting processes due to undercuts, backdraft and other issues. With the advent of binder-based 3D printing technology, sand molds and cores can be produced to make these optimized designs as metal castings.
2017-03-28
Technical Paper
2017-01-1225
Jayaraman Krishnasamy, Martin Hosek
An advanced electric motor with hybrid-field topology has been developed for automotive traction applications. Departing from the conventional radial- and axial-field designs, the hybrid-field motor features three-dimensional magnetic flux paths in a geometry that maximizes the effective volume for magnetic flux flow. The three-dimensional flux paths are enabled by an isotropic soft magnetic material, which has been engineered to replace conventional laminated winding cores with solid isotropic components. The material is produced by a novel additive-manufacturing process based on spray forming. The paper introduces the spray-forming process for motor stator components and presents a conceptual design of the traction motor developed around them, including the motor topology, stator construction and rotor construction. The stator features a spray-formed core with three-dimensional magnetic flux paths, high-density windings and direct liquid cooling.
2017-03-28
Technical Paper
2017-01-0284
Sajjad Raeisi
Additive manufacturing has been a promising technique for producing sophisticated porous structures. The pore's architecture and infill density percentage can be easily controlled through additive manufacturing methods. This paper reports on development of polymer extruded cross sections ad lightweight materials manufactured using additivemanufacturing technology. In this study, three types of crosssections with same 2D porosity are generated by way of particular techniques. a) The regular cross section of hexagonal honeycomb, b) The heterogeneous pore distribution of closed cell aluminum foam cross section obtained from image processing and c) linearly patterned topology optimized 2D unit cell undercompressive loading condition. All the cross sections have the same cavity to matter ratio on their 2D configuration. The samples are extruded to produce 3D CAD model of honeycomb shape porous structure.
2017-03-28
Technical Paper
2017-01-0283
Mohammad Alam, Navid Nazemi, Ruth Jill Urbanic, Syed Saqib, Afsaneh Edrisy
Laser cladding is a novel process of surface coating, and researchers in both academia and industry are developing additive manufacturing solutions for large, metallic components using this process. There are many interlinked process parameters (e.g. laser power, laser speed and powder feed rate) associated with laser cladding. These process parameters have a direct impact on the resultant bead geometry and the microhardness profile throughout the bead zone, dilution zone and heat affected zone (HAZ). A set of single bead laser cladding experiments were done using a 4 kW fibre laser coupled with a 6-axis robotic arm for 420 martensitic stainless steel. A design of experiments approach was taken to explore a wide range of process parameter settings.
2017-03-28
Technical Paper
2017-01-0316
Kiran Mallela, Andrey Ilinich, S Luckey, Danielle Zeng, Yuan Gan
Aluminum extrusions are used in the automotive industry for body structure applications requiring cross-section design flexibility, high section stiffness, and high strength. Heat-treatable 6xxx series extrusion alloys have typically been used in automotive due to commercial availability, competitive cost, high strength, and impact performance. This paper presents a characterization study of mechanical properties of 6xxx series aluminum extrusions using digital image correlation (DIC). DIC has been used to capture spatial strain distribution and its evolution in time during material deformation. The materials of study were seamless and structural 6061 and 6082 extrusions. The alloys have been tensile tested using an MTS load frame with a dual optical camera system to capture the stereoscopic digital images. Notable results include the differing anisotropy of seamless and structural extrusions, as well as the influence of artificial aging on anisotropy.
2017-03-28
Technical Paper
2017-01-0288
Hai Wu, Meng-Feng Li
Robots are widely used in industry in the repeating tasks to free human from the tedious labor. There are some tasks that are either complex itself or simple but interacting with complex environment. In these cases, human are not replaceable and human/robot interactions are inevitable. Design and developing human performance enhancing robotic devices is applicable to not only industrial assembling robots and moving/carrying assist devices, but also can be extended to areas like medical surgical robots, exo-skeleton etc. The benefit is to utilize the human perceiving and analyzing capability to the difficult tasks and environments, thereby the main purpose and challenge of such system is to implement the intuitivity of the operator in the system control. The admittance control approach is often adopted in human/robot interaction control. It is noticed that the control designed with a fixed pair of virtual mass and damping cannot reach desirable performance of handling.
2017-03-28
Technical Paper
2017-01-0326
Samuel J. Tomlinson, Martin J D Fisher, Thomas Smith, Kevin Pascal
When sealing an application with a radial O-ring system design there is a balance between O-ring function and ease of assembly. Often times the assembly insertion force rises to the point of unacceptable manufacturing ergonomic practice. Designs are released into production with these high insertion forces while manufacturing operators struggle to assemble parts leaving opportunity for potential operator injury. Several variables impacting O-ring system insertion forces were tested to quantify the effects. Results were analyzed to identify design controls that could be implemented from an early design phase optimizing functionality and ease of assembly.
2017-03-28
Technical Paper
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
Technical Paper
2017-01-1709
Zhigang Wei, Sarat Das, Ryan Barr, Greg Rohrs, Robert Rebandt, Xiao Wu, HongTae Kang
Recent stringent government regulations on emission control and fuel economy drive the vehicles and their associated components and systems to the direction of lighter weight. However, the achieved lightweight must not be obtained by sacrificing other important performance requirements such as manufacturability, strength, durability, reliability, safety, noise, vibration and harshness (NVH). Additionally, cost is always a dominating factor in the lightweight design of automotive products. Therefore, a successful lightweight design can only be accomplished by better understanding the performance requirements, the potentials and limitations of the designed products, and by balancing many conflicting design parameters. The combined knowledge-based design optimization procedures and, inevitably, some trial-and-error design iterations are the practical approaches that should be adopted in the lightweight design for the automotive applications.
2017-03-28
Technical Paper
2017-01-1472
Niels Pasligh, Robert Schilling, Marian Bulla
Rivets, especially self-piercing rivets (SPR), are one primary joining technology for vehicles using aluminum. SPR are mechanical joining elements that are used to connect sheets to create a structure to build a body in white (BiW). To ensure the structural performance of a vehicle in crash load cases it is necessary to describe physical occurring failure modes under overloading conditions in simulations. One failure mode is joint separation which need to be precisely predicted by a crash simulation. Within crash simulations a detailed analysis of a SPR joint and its process history would require a very high computational effort. The conflict between a detailed SPR joint and a macroscopic vehicle model need to solved by developing an approach that can handle an accurate macroscopic prediction of SPR behavior with a defined strength level with less computational effort. One approach is using a cohesive material model for a SPR connection.
2017-03-28
Technical Paper
2017-01-1529
Nicholas Simmonds, John Pitman, Panagiotis Tsoutsanis, Adrian Gaylard, Wilko Jansen, Karl Jenkins
Cooling drag has traditionally proven to be a difficult flow phenomenon to predict using computational fluid dynamics. With the advent of grille shutter systems, the need to accurately pre-dict this quantity during vehicle development has become more pressing. A comprehensive study is presented in the paper of three automotive models with different cool-ing drag deltas using the commercial CFD solver STARCCM+. The notchback DrivAer model with under-hood cooling provides a popular academic benchmark alongside two fully-engineered production cars; a large saloon (Jaguar XJ) and an SUV (Land Rover Range Rover). Previous studies detail the differences in the flow field; highlighting the interaction between the exiting under-hood cooling flow, and the wheel and base wakes for open and closed grilles.
2017-03-28
Technical Paper
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
Technical Paper
2017-01-0255
Malli Kartheek Yalamanchili, Nitin Sharma, Kevin Thomson
The crashworthiness of body-in-white (BIW), plays a very vital role in the full vehicle crash performance. The structural integrity of BIW is controlled via strength of the spot welds and adhesives that are often considered as only entities to hold the parts together. However optimizing the welds and/or adhesives can not only reduce the number of connections but also improve the structural crashworthiness. This paper discusses the optimization of full vehicle structural performance and the length of adhesives in the BIW for the small overlap crash event. The variables included in the study were length of the adhesives and gage variables, defined in the front end structure of the vehicle. A parametric model was created using ANSA and iSight was used to generate design of experiments (DOE). Automated design generation using ANSA followed by automated script based post-processing was done. The optimization was done using metamodel generated for the crash event.
2017-03-28
Technical Paper
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
Technical Paper
2017-01-0481
Xian Jun sun, Patricia Tibbenham, Jin Zhou, Danielle Zeng, Shiyao Huang, Li Lu, Xuming Su
It is important to investigate on the weld line of injection molded part because the weld line area could induce potential failure for structural application. In this paper, the weld line factor(W-L factor) was adopted to describe the strength reduction to the bulk strength due to the appearance of weld line. There were five engineering thermoplastics involved in this study, including neat PP, talc filled PP, TPO, ABS and PC/ABS. The experimental design was used to investigate on four main injection molding parameters (melt temperature, mold temperature, injection speed and packing pressure). Both the bulk and weld line samples were prepared at each process settings. The sample strength was obtained by the tensile tests under two levels of testing speeds(5mm/min and 200mm/min) and testing temperatures(room temperature and -30oC). The results showed that different materials had various W-L factors. For neat PP, the W-L factor was highest and independent to injection mold parameters.
2017-02-01
Book
He Tang
Proven technologies and processes are explored in this examination of modern automotive manufacturing. Fundamentals and applications, as well as new advances are discussed as the author bridges the gap between academic research and industrial practice. Having held positions as both a University Professor and as a Lead Engineering Specialist in industry, the author presents a concise understanding that reflects both technical and managerial perspectives with the aim of providing improvement through practical methods. Each chapter includes review questions and research topics, and, in addition, analysis problems are often included that comprehensively address: • Automotive Industry and Competition • Manufacturing Operations • Joining and Paint Processes • Production Operations and Quality Management • Performance Improvement Directly extracted and summarized from automotive manufacturing practices, this book serves as a fundamental manual.
CURRENT
2017-01-19
Standard
AMS5639J
This specification covers a corrosion-resistant steel in the form of bars, wire, forgings, mechanical tubing, flash welded rings, and stock for forging or flash welded rings.
CURRENT
2017-01-18
Standard
AMS5618J
This specification covers a premium aircraft-quality corrosion-resistant steel in the form of bars, wire, forgings, and forging stock.
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