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Viewing 1 to 18 of 18
2005-04-11
Technical Paper
2005-01-1908
K. S. Choi, J. Pan, S. Ho
In this paper, the effects of roller geometry on contact pressure and residual stress in crankshaft fillet rolling are investigated by a two-dimensional finite element analysis. The fillet rolling process is first introduced to review some characteristics of the rolling tools. A two-dimensional plane strain finite element analysis is then employed to qualitatively investigate the influence of the roller geometry. Computations have been conducted for eight different contact geometries between the primary roller and the secondary roller to investigate the geometry effect on the contact pressure distribution on the edge of the primary roller. Fatigue parameters of the primary rollers are also estimated based on the Findley fatigue theory. Then, computations have been conducted for three different contact geometries between the primary roller and the crankshaft fillet to investigate the geometry effect on the residual stress distribution near the crankshaft fillet.
2006-04-03
Technical Paper
2006-01-1433
Matthew S. Walp, Astrid Wurm, John F. Siekirk, Ajit K. Desai
Significant efforts are underway in the automotive industry to reduce vehicle weight while maintaining performance and cost competitiveness. One such effort is the use of advanced high strength steels (AHSS) as the primary body materials method to meet weight targets using the existing automotive manufacturing infrastructure. Issues related to the stamping of AHSS are well known, and significant hurdles still exist for successful implementation. Due to material strength and mechanical behavior, springback is a major hurdle in forming AHSS. While working to form AHSS parts and reduce springback, press shops have encountered a new fracture type. The term shear fracture or local elongation has been loosely used to specify these fractures, which occur at part radii under low strains in multiphase AHSS. These fractures cause design limitations and manufacturing uncertainty.
2007-04-16
Technical Paper
2007-01-0342
Matthew S. Walp
The automotive industry is pursuing significant cost competitive efforts to reduce vehicle weight while maintaining or improving durability and impact performance. One such effort for the body shell structure is the utilization of advanced and ultra high strength steels (AHSS and UHSS) using the existing automotive manufacturing infrastructure. Common AHSS and UHSS steels include Dual Phase (DP), Transformation Induced Plasticity (TRIP), Partial Martensitic (PM) and others. The use of these multiphase high strength steels for impact dependent components has resulted in the need for further material characterization in order to better predict impact performance and guide new material development. This paper addresses the material properties and microstructural influences on impact behavior of advanced and ultra high strength steels through the use of laboratory tests and component level testing.
2004-03-08
Technical Paper
2004-01-1498
K. S. Choi, J. Pan, S. Ho
In this paper, the fatigue failure of the primary roller used in a crankshaft fillet rolling process is investigated by a failure analysis and a two-dimensional finite element analysis. The fillet rolling process is first discussed to introduce the important parameters that influence the fatigue life of the primary roller. The cross sections of failed primary rollers are then examined by an optical microscope and a Scanning Electron Microscope (SEM) to understand the microscopic characteristics of the fatigue failure process. A two-dimensional plane strain finite element analysis is employed to qualitatively investigate the influences of the contact geometry on the contact pressure distribution and the Mises stress distribution near the contact area. Fatigue parameters of the primary rollers are then estimated based on the Findley fatigue theory.
2004-03-08
Technical Paper
2004-01-1501
V. Yu, W. Y. Chien, K. S. Choi, J. Pan, D. Close
Resonant frequencies of a resonant bending system with notched crankshaft sections are obtained experimentally and numerically in order to investigate the effect of notch depth on the drop of the resonant frequency of the system. Notches with the depths ranging from 1 to 5 mm, machined by an EDM (Electrical-Discharging Machining) system, were introduced in crankshaft sections at the fillet between the main crank pin and crank cheek. The resonant frequencies of the resonant bending system with the crankshaft sections with various notch depths were first obtained from the experiments. Three-dimensional finite element models of the resonant bending system with the crankshafts sections with various notch depths are then generated. The resonant frequencies based on the finite element computations are in good agreement with those based on the experimental results.
2003-06-23
Technical Paper
2003-01-2271
Valerie Hovland, Ahmad Pesaran, Richard M. Mohring, Ian A. Eason, Gregory M. Smith, Doanh Tran, Rolf Schaller, Tom Smith
The National Renewable Energy Laboratory (NREL) collaborated with Millennium Cell and DaimlerChrysler to study heat and water management in a sodium borohydride (NaBH4) storage/processor used to supply hydrogen to a fuel cell in an automotive application. Knowledge of heat and water flows in this system is necessary to maximize the storage concentration of NaBH4, which increases vehicle range. This work helps evaluate the NaBH4 system's potential to meet the FreedomCAR program technical target of 6 wt% hydrogen for hydrogen storage technologies. This paper also illustrates the advantages of integrating the NaBH4 hydrogen processor with the fuel cell.
2007-04-16
Technical Paper
2007-01-0986
Sung-Tae Hong, Curt A Lavender, John R Boughton, Kurt M. Knop, Allan McGowan, David W Skilton
The effect of hydroforming on the mechanical properties and dynamic crush behaviors of tapered aluminum 6063-T4 tubes with octagonal cross section are investigated by experiments. First, the thickness profile of the hydroformed tube is measured by non-destructive examination technique using ultrasonic thickness gauge. The effect of hydroforming on the mechanical properties of the tube is investigated by quasi-static tensile tests of specimens prepared from different regions of the tube based on the thickness profile. The effect of hydroforming on the dynamic crush behaviors of the tube is investigated by axial crush tests under dynamic loads. Specimens and tubes are tested in two different heat treatment conditions: hydroformed-T4 (as-received) and T6. The results of the quasi-static tensile tests for the specimens in hydroformed-T4 condition show different amounts of work hardening depending on the regions, which the specimens are prepared from.
1999-09-28
Technical Paper
1999-01-3202
N Suresh, John G. Argeropoulos, Craig Patterson, Del Schroeder
The automobile industry is seeing an increased need for the application of plastics and their derivatives in various forms such as fiber reinforced plastics, in the design and manufacture of various automotive structural components, to reduce weight, cost and improve fuel efficiency. A lot of effort is being directed at the development of structural plastics, to meet specific automotive requirements such as stiffness, safety, strength, durability and environmental standards and recyclability. This paper presents the concept of reinforcing large injection molded fiber reinforced body panels with structural uni-directional fibers (carbon, graphite, kevlar or fiber glass) wound in tension around the body panels by filament winding technique. Structural uni-directional fibers in tension wound around the fiber reinforced plastic inner body panels would place these body panels under compression.
1999-09-28
Technical Paper
1999-01-3160
Daryl J. Trate, John A. Griffin, Michael Zickel
An early development vehicle experienced an unusually high rate of windshield breakage. Most breaks were identified as due to impact, but the severity of impact was low. It was reasoned that the windshield should possess a greater level of robustness to impact. Many theories were put forth to explain the breakage data. It was universally agreed that the unusual breakage rate could be due to only one condition, but its source was indefinite. The condition present must be tensile stress. One of three situations were considered regarding its source: 1) the tensile stress was present in the glass after manufacture due to improper annealing; 2) the installation of the windshield into the vehicle body put the glass into stress; 3) some combination of the other two sources. A gray-field polariscope was used to measure the stresses of the windshield from both the manufacturing process as well as the installation in the vehicle.
1999-03-01
Technical Paper
1999-01-1002
Ming F. Shi, Li Zhang
With the increased application of high strength steels in automotive body-in-white parts for weight reduction purposes, more emphasis is focused on springback as a major problem in stamping operations, in addition to panel breakage and wrinkling. Computer simulations using the finite element analysis (FEA) have been used to predict springback during early stages of die development processes to minimize potential springback related problems in production. However, the reliability of the springback simulation results relies directly on the accuracy of stress distributions from the forming simulation. Its complexity has brought many challenges not only to engineers and researchers in areas of FEA development and material modeling but also to FEA code end users. It is shown from this study that the springback simulation results vary with the yield criterion used in the forming simulation.
2000-04-02
Technical Paper
2000-01-1597
Joseph Hassan, Guy Nusholtz, Marlon D Forrest
Stochastic simulation is used to account for the uncertainties inherent to the system and enables the study of crash phenomenon. For analytical purposes, random variables such as material crash properties, angle of impact, human response and the like can be characterized using statistical models. The methodology outlined in this approach is based on using the information about the probability of random variables along with structural behavior in order to quantify the scatter in the structural response. Thus the analysis gives a more complete picture of the actual simulation. Practical examples for the use of this technique are demonstrated and an overview of this approach is presented.
2001-03-05
Technical Paper
2001-01-0926
Gregory M. Pannone, John D. Mueller
Catalyst systems utilizing ceramic and metallic substrates were compared to assess the influence of various substrate parameters on the exhaust gas conversion efficiency and flow restriction. In particular, the substrate surface area, substrate specific heat capacity, and substrate volume were all evaluated for their importance in estimating the conversion efficiency of the catalyst system. Additionally, substrate open frontal area and cell hydraulic diameter were compared against exhaust restriction performance.
1999-10-10
Technical Paper
1999-01-3389
Chris Watson, Tom Millsap
In an effort to ensure that the characteristics of prototype friction materials do not differ from those of the “same” material when introduced into volume production and that, in production, these characteristics do not vary over time, DaimlerChrysler has instigated the processes of Shoe and Lining Fingerprinting and Production Variation Reduction. For the launch of the 1999 Jeep Grand Cherokee the concept of Production Variation Reduction was extended by the Jeep Platform and BBA Friction, Inc., to 25 pre-production batches of material to eliminate prototype to production variability.
2000-03-06
Technical Paper
2000-01-1109
Suresh C. Rama, J. M. Zhang, Changqing Du, Yang Hu, Hua-Chu Shih, S.-D. Liu
The use of commercial finite element analysis (FEA) software to perform stamping feasibility studies of automotive components has grown extensively over the last decade. Although product and process engineers have now come to rely heavily on results from FEA simulation for manufacturability of components, the prediction of springback has still not been perfected. Springback prediction for simple geometries is found to be quite accurate while springback prediction in complex components fails to compare with experimental results. Since most forming simulation FEA software uses a dynamic explicit solution method, the choice of various input parameters greatly affects the prediction of post formed stresses in the final component. Accurate stress prediction is critical for determination of springback, therefore this study focuses on the effects of some of the simulation parameters such as, element size, tool/loading speed and loading profile.
2003-03-03
Technical Paper
2003-01-1223
Basil Joseph, Pradeep Attibele, Yung-Li Lee, Salman Haq
Once a vehicle powertrain is designed and the first prototype is built, extensive on-board instrumentation and testing needs to be carried out at the proving grounds (PG) to generate load histograms for various components. The load histograms can then be used to carry out durability tests in the laboratory. When a component in the vehicle powertrain is changed, the load histograms need to be generated again at the proving grounds. This adds much time and money to the vehicle's development. The objective is to develop a virtual powertrain model that can be simulated through a powertrain endurance driving cycle in order to predict torque histograms and total damage. The predictions are then correlated against measured data acquired on a test vehicle that was driven through the same driving cycle at the proving grounds.
2003-03-03
Technical Paper
2003-01-1238
Dennis Davidson, Larry Thompson, Frank Lutze, Butch Tiburcio, Kevin Smith, Cindy Meade, Tom Mackie, Duncan McCune, Herb Townsend, Rebecca Tuszynski
The Auto/Steel Partnership Corrosion Project Team has completed a perforation corrosion test program consisting of on-vehicle field exposures and various accelerated tests. Steel sheet products with eight combinations of metallic and organic coatings were tested, utilizing a simple crevice coupon design. On-vehicle exposures were conducted in St. John's and Detroit for up to seven years to establish a real-world performance standard. Identical test specimens were exposed to the various accelerated tests, and the results were compared to the real-world standard. This report documents the results of these tests, and compares the accelerated test results (including SAE J2334, GM9540P, Ford APGE, CCT-I, ASTM B117, South Florida Modified Volvo, and Kure Beach (25-meter) exposures) to the on-vehicle tests. The results are compared in terms of five criteria: extent of corrosion, rank order of material performance, degree of correlation, acceleration factor, and control of test environment.
2000-11-13
Technical Paper
2000-01-3543
Hubert Gramling, Robert Hubbard
A comparative investigation of airbag and HANS driver safety systems was carried out (HANS, is a Registered Trademark in the U.S.A.). With both systems, head and neck loads were reduced from potentially fatal values to values well below the injury threshold. Both systems performed similarly in reducing the potential for driver injury. For this reason and given the high costs of development and testing, there is no justification for further development of airbags for racing.
2000-11-13
Technical Paper
2000-01-3541
Hubert Gramling, Robert Hubbard
This paper describes additional and more recent results from the DaimlerChrysler study of HANS that includes a sensitivity analysis of HANS performance to variations in crash dummy neck length and other impact test conditions. The objective of the tests was to determine the robustness of the HANS concept in a variety of conditions that might occur in actual use. The results show that the variations in test parameters do effect injury measures from the crash dummy, but HANS provides substantial reductions in injury potential in all cases compared to not using HANS. Also, no injuries were indicated with HANS.
Viewing 1 to 18 of 18

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