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Viewing 1 to 30 of 76
2005-05-16
Technical Paper
2005-01-2314
Sanjay K. Mahajan, Eric Denys, Jun-Chul Bae, Tinghui S. Shi, Kee H. Im
Brake insulators often offer optimal solutions to squeal noise. In the process of engineering solutions to reduce the brake noise, a system-level finite element complex eigenvalue analysis is often used and has gained popularity in recent years. Models of insulators have also been proposed for system-level evaluation, however many challenges remain in efficiently implementing an insulator model, owing to complexities of the insulator component model. The complexities arise from the visco-elastic behavior (primarily the frequency and temperature dependence), and the thin polymer/steel multi-layer nature of the construction - typical in an insulator. As a first part of a joint investigation, this paper explores the nature of frequency and temperature dependence in insulator models and reduces the cumbersome multi-layer model into a simpler form that can be more easily implemented in a typical brake system stability analysis.
2006-04-03
Technical Paper
2006-01-0522
Joy A. Hines, Robert C. McCune, John E. Allison, Bob R. Powell, Larry J. Ouimet, William L. Miller, Randy Beals, Lawrence Kopka, Peter P. Ried
Over the past five years, the US Automotive Materials Partnership (USAMP) has brought together representatives from DaimlerChrysler, General Motors, Ford Motor Company and over 40 other participant companies from the Mg casting industry to create and test a low-cost, Mg-alloy engine that would achieve a 15 - 20 % Mg component weight savings with no compromise in performance or durability. The block, oil pan, and front cover were redesigned to take advantage of the properties of both high-pressure die cast (HPDC) and sand cast Mg creep- resistant alloys. This paper describes the alloy selection process and the casting and testing of these new Mg-variant components. This paper will also examine the lessons learned and implications of this pre-competitive technology for future applications.
2006-04-03
Technical Paper
2006-01-0605
S. N. Thakur, J. R. McMillen, M. L. Holly, P. K. Samal
Durability requirements for exhaust materials have resulted in the increased use of stainless steels throughout the exhaust system. The conversion of carbon steel exhaust flanges to stainless steel has occurred on many vehicles. Ferritic stainless steels are commonly used for exhaust flanges. Flange construction methods include stamped sheet steel, thick plate flanges and powder metal designs. Flange material selection criteria may include strength, oxidation resistance, weldability and cold temperature impact resistance. Flange geometry considerations include desired stiffness criteria, flange rotation, gasket/sealing technique and vehicle packaging. Both the material selection and flange geometry are considered in terms of meeting the desired durability and cost. The cyclic oxidation performance of the material is a key consideration when selecting flange materials.
2005-04-11
Technical Paper
2005-01-1833
Mark A. Gehringer
This paper describes an axle gear whine noise reduction process that was developed and applied using a combination of experimental and analytical methods. First, an experimental Transfer Path Analysis (TPA) was used to identify major noise paths. Next, modeling and forced response simulation were conducted using the Hybrid FEA-Experimental FRF method known as HYFEX [1]. The HYFEX model consisted of an experimental FRF representation of the frame/body and a finite element (FE) model of the driveline [2] and suspension. The FE driveline model was calibrated using experimental data. The HYFEX model was then used to simulate the axle noise reduction that would be obtained using a modified frame, prior to the availability of a prototype. Hardware testing was used as the final step in the process to confirm the results of the simulation.
2006-04-03
Technical Paper
2006-01-0072
Su Xu, Glenn Williams, Guowu Shen, Réal Bouchard, Mahi Sahoo, Richard Osborne
For automotive applications at elevated temperatures, the need for sufficient creep resistance of Mg alloys is often associated with retaining appropriate percentages of initial clamp loads in bolt joints. This engineering property is often referred to as bolt-load retention (BLR); BLR testing is a practical method to quantify the bolt load with time for engineering purposes. Therefore, standard BLR test procedures for automotive applications are desired. This report summarizes the effort in the Structural Cast Magnesium Development (SCMD) project under the United States Automotive Materials Partnership (USAMP), to provide a technical basis for recommending a general-purpose and a design-purpose BLR test procedures for BLR testing of Mg alloys for automotive applications. The summary includes results of factors influencing BLR and related test techniques from open literature, automotive industry and research carried out in this laboratory project.
1998-02-23
Technical Paper
980718
Tim Ferris, Muriel Finken, Bruce Dziadzio, Terry Bishop
Over the past 20 years, polyvinyl chloride (PVC) has almost replaced metal in stationary glass reveal moldings with dramatic part cost savings on cars and trucks world-wide. The process of assembly is generally simple and convenient but to replace a reveal molding can be difficult. Many times, in order to replace the molding, it may also be necessary to replace or reseal the glass. In short, PVC reveal moldings, relatively inexpensive parts, are very expensive to service. Outside of general assembly and processing issues, there are 5 variables that may cause a failure in the performance of a stationary glass reveal molding. They are as follows: material degradation, crystallization, plasticizer loss, material properties, and molded-in stress. Because of modern standard PVC formulations and the material requirements of most automotive companies, material degradation, crystallization and plasticizer loss do not commonly cause failure. Material properties and molded-in stress do.
1998-02-23
Technical Paper
980689
Joe H. Morrill, Thomas Achatz, Abolhassan Khosrovaneh
A method is presented to process random vibration data from a complete road durability test environment as stationary segments and then develop test profiles based on fatigue content of their power spectral densities. Background is provided on existing techniques for estimating fatigue damage in the frequency domain. A general model for stress response to acceleration is offered to address the vibration test's requirement for acceleration data and the fatigue prediction method's requirement for stress data. With these tools, the engineer can extend test correlation beyond failure modes to include retention of estimated fatigue damage. Recommendations allow for test time compression from editing and improve existing exaggeration methods.
1998-02-23
Technical Paper
980978
James W. Jenkins, Kathleen M. Kane
Minor surface defects in the clearcoat film are common place realities in modern automotive painting operations. Finessing and polishing processes are required to remove these defects and restore the clearcoat to its original condition. Evaluation of new clearcoat technologies and polishing processes has always been very subjective. This drove the development of a standardized test method for evaluating the finessability of a clearcoat. In this paper the authors will compare and contrast the differences between the traditional method used to evaluate finessability with the newly developed standardized method. The standardized method shows distinct advantages when evaluating different clearcoat technologies and polishing processes.
2006-04-03
Technical Paper
2006-01-0992
James C. Tebbe, Vivek Chidambaram, Jason T. Kline, Sam Scime, Manish P. Shah, Mine Tasci, David Zheng
Automotive engineering development processes are growing more dependent on the use of multi-body dynamic (MBD) models for generating vehicle loads that at one time could only be measured using physical hardware. A certain technique combines these two approaches using a minimal set of physical measurements to excite a vehicle MBD model for predicting loads at various vehicle interfaces. This approach eliminates the use of a tire model, often the roadblock in MBD-based loads prediction simulations. However, for various reasons, the direct application of loads to a model can lead to problems with the simulation. Alternatively, the model can be artificially constrained but this also has its disadvantages. The purpose of this paper is to present a loads prediction technique that relaxes the use of artificial boundary conditions for applications involving the input of measurements to an MBD model.
2006-04-03
Technical Paper
2006-01-0979
Abolhassan Khosrovaneh, Ravi Pattu
In the automotive industry, vehicle durability analysis is based on test schedule encompassing multiple road surfaces (events) including rough roads, potholes, etc. Traditionally, in the Computer Aided Engineering (CAE) world, road load data for various road surfaces are measured/predicted and fatigue life is predicted for each individual road surface. Fatigue life for the complete test schedule is then calculated with Miner’s rule by summing fatigue damage for each road surface with an appropriate number of repetitions. A major pitfall of this approach is that it does not consider the effect of the largest rainflow range across the entire test schedule. The method described in this paper was developed to perform fatigue analysis of structures subjected to diverse road surfaces and also consider the case in which the maximum overall peak and minimum overall valley do not occur over the same road surface.
2006-04-03
Technical Paper
2006-01-0780
Johann Blaha, Franz Langmayr, Soeren Schackert, Cherng-Chi Chang, Diwakar Krishnaiah, Paul N. Crepeau
Two thread forming processes, rolling and cutting, were studied for their effects on fatigue in cast aluminum 319-T7. Material was excised from cylinder blocks and tested in rotating-bending fatigue in the form of unnotched and notched specimens. The notched specimens were prepared by either rolling or cutting to replicate threads in production-intent parts. Cut threads exhibited conventional notch behavior for notch sensitive materials. In contrast, plastic deformation induced by rolling created residual compressive stresses in the notch root and significantly improved fatigue strength to the point that most of the rolled specimens broke outside the notch. Fractographic and metallographic investigation showed that cracks at the root of rolled notches were deflected upon initiation. This lengthened their incubation period, which effectively increased fatigue resistance.
2007-04-16
Technical Paper
2007-01-0790
Vesna Savic, Louis G. Hector
Tensile measurements and fracture surface analysis of low carbon heat-treated boron steel are reported. Tensile coupons were quasi-statically deformed to fracture in a miniature tensile testing stage with custom data acquisition software. Strain contours were computed via a digital image correlation method that allowed placement of a digital strain gage in the necking region. True stress-true strain data corresponding to the standard tensile testing method are presented for comparison with previous measurements. Fracture surfaces were examined using scanning electron microscopy and the deformation mechanisms were identified.
2007-04-16
Technical Paper
2007-01-0417
Francine Bovard, Janice Tardiff, Tracie Jafolla, Duncan McCune, Greg Courval, Kevin A. Smith, Fred Lee, John Repp, Sridhar Ramamurthy, R. James Shaffer, Florina M. Vartolas
Since 2000, an Aluminum Cosmetic Corrosion task group within the SAE Automotive Corrosion and Protection (ACAP) Committee has existed. The task group has pursued the goal of establishing a standard test method for in-laboratory cosmetic corrosion evaluations of finished aluminum auto body panels. A cooperative program uniting OEM, supplier, and consultants has been created and has been supported in part by USAMP (AMD 309) and the U.S. Department of Energy. Prior to this committee's formation, numerous laboratory corrosion test environments have been used to evaluate the performance of painted aluminum closure panels. However, correlations between these laboratory test results and in-service performance have not been established. Thus, the primary objective of this task group's project was to identify an accelerated laboratory test method that correlates well with in-service performance.
2004-03-08
Technical Paper
2004-01-1509
Gaurav Anand, Milind Mahajan, Nagendra Jain, Balaji Maniam, Todd M. Tumas
e-Thermal is a vehicle level thermal analysis tool developed by General Motors to simulate the transient performance of the entire vehicle HVAC and Powertrain cooling system. It is currently in widespread (global) use across GM. This paper discusses the details of the air-conditioning module of e-Thermal. Most of the literature available on transient modeling of the air conditioning systems is based on finite difference approach that require large simulation times. This has been overcome by appropriately modeling the components using Sinda/Fluint. The basic components of automotive air conditioning system, evaporator, condenser, compressor and expansion valve, are parametrically modeled in Sinda/Fluint. For each component, physical characteristics and performance data is collected in form of component data standards. This performance data is used to curve fit parameters that then reproduce the component performance.
2004-03-08
Technical Paper
2004-01-0814
Y. J. Chao, Kangping Wang, Yih-Charng Deng
Inertia force during dynamic testing exists in any testing system. A generic system is analyzed using the principle of rigid body dynamics. It is shown that the load recorded by a load cell includes both the load experienced by the test specimen and the inertia force from the mass between the specimen and the load cell, when the load cell is placed on the fixed side of the test specimen. An impact fixture designed for spot weld strength test was then studied as an example. Test data were collected and analyzed to show the effect of inertia on the impact strength of the spot weld.
2004-03-08
Technical Paper
2004-01-0832
Kuo-Kuang Chen, Ronald J. Soldaat, Robert M. Moses
Free expansion of straight tubes is the simplest test to evaluate tube properties for hydroforming applications and to provide basic understanding of the mechanics of tube hydroforming. A circular cylindrical tube is sealed at both ends and fluid, usually water, is pumped into the tube to increase its internal pressure to bulge and burst the tube. Previous numerical simulations of the free expansion tube test were limited to modeling the midsection of the tube under various assumptions of deformation path. The simulation results obtained deviated from the experimental results under all simulation conditions considered. A new model is developed in this paper in which the whole tube is simulated instead of considering only its mid-section. Judged by the pressure-expansion relations, the model accurately predicted free expansion hydroforming tests results.
2005-04-11
Technical Paper
2005-01-1326
Brian Breakiron, James R. Fekete
This paper will describe an investigation of the formability of high strength steel (HSS) laser welded blanks (LWBs). Anticipated combinations of thickness and steel grades, including high strength low alloy (HSLA) and dual phase (DP) steels were selected. The blanks were characterized through chemical analysis and mechanical testing, as well as microstructural analysis of the weld. Samples were strained in a limiting dome height tester. Weld line movement, dome height and strain at failure were then measured. Data from these tests resulted in development of forming limit diagrams, and allowed correlation of weld line movement to forming conditions. In part, the results showed that the presence of the weld has a negative influence on formability, and that balancing the load carrying capacity of each side of the blank results in minimum weld line movement in the blanks.
2005-04-11
Technical Paper
2005-01-0920
Carl-Anders Hergart, Abdelilah Louki, Norbert Peters
Heat transfer to the combustion chamber walls constitutes a significant portion of the overall energy losses over the working cycle of a direct injection (DI) diesel engine. In the last few decades, numerous research efforts have been devoted to investigating the prospects of boosting efficiency by insulating the combustion chamber. Relatively few studies have focused on the prospects of reducing emissions by applying combustion chamber insulation. A main purpose of this study is to assess the potential of reducing in-cylinder soot as well as boosting aftertreatment performance by means of partially insulating the combustion chamber. Based on the findings from a conceptual study, a Low Heat Rejection (LHR) design, featuring a Nimonic 80A insert into an Aluminum piston, was developed and tested experimentally at various loads in a single-cylinder Hatz-engine.
2005-04-11
Technical Paper
2005-01-0340
Jonathon Aragones, Kasi Goundan, Scott Kolp, Richard Osborne, Larry Ouimet, William Pinch
Since its very beginning in 1953, Corvette has been a pioneer in light weight material applications. The new 6th generation corvette high performance Z06 model required aggressive weight savings to achieve its performance and fuel economy targets. In addition to aluminum body structure and some carbon fiber components, the decision to use a magnesium front crossmember was identified to help achieve the targets. An overview of the Structural Cast Magnesium Development (SCMD) project will be presented which will provide information on key project tasks. Project focus was to develop the science and technical expertise to manufacture and validate large structural magnesium castings, which provide a weight reduction potential of 35 percent with respect to aluminum. The die cast magnesium cradle is being produced from a Mg-Al-RE alloy, designated AE44, for high temperature creep and strength performance as well as casting ductility requirements.
2005-04-11
Technical Paper
2005-01-0337
Naiyi Li, Richard Osborne, Bruce Cox, Donald Penrod
The Structural Cast Magnesium Development Project is a jointly sponsored effort by the US Department of Energy (DOE) and the US Council for Automotive Research (USCAR) Automotive Metals Division (AMD) to identify and resolve technical and manufacturing issues that limit the light weighting opportunities of applying large-scale structural cast magnesium automotive components. This project, which began in the end of year 2001, comprises General Motors, Ford, DaimlerChrysler and thirty-four other North America companies and organizations. The project has its overall objective set to determine the technical feasibility and practicality of producing and implementing a one-piece front engine cradle casting. This paper provides an overview of the project scopes and up-to-date accomplishments.
2005-04-11
Technical Paper
2005-01-0357
Chung-Yeh Sa, Xinhai Zhu
Sheet metal forming processes change the material properties due to work hardening (or softening) in the thickness direction as well as throughout the entire part. At the same time, uneven thickness distribution, mostly thinning, occurs as the result of forming. This is true for all commonly used sheet metal forming processes including stamping (deep drawing), tube hydroforming, sheet hydroforming and super plastic forming. The effects from forming can sometimes strongly influence the structural performance. Though the CAE analysts have been trying to consider forming effect in their models for performance simulations, there was no easy way to do it consistently and reliably. Some analysts have been trying to modify the initial gage or yield strength to compensate for the property change due to forming. Replace the model with the formed panel is not feasible due to the mesh density difference.
2005-04-11
Technical Paper
2005-01-0088
Frank Lee, Krishna Murali, Andrew Heath, Raju Gandikota
A computer assisted development technique for Quick Plastic Forming parts [1] is described, based on the simulation program PAM-STAMP [2]. The technique allows thickness changes during forming to be accurately considered in the development process without physical trials. Process pressure cycles, which provide for maximal material formability, can be determined with a single simulation. The paper describes new program features, which reduce modeling effort and increase simulation accuracy. Various validation examples and industrial case studies are also presented, demonstrating current capabilities.
2005-04-11
Technical Paper
2005-01-0803
Jiangtao Song, Zissimos P. Mourelatos, Randy J. Gu, Paul N. Crepeau
The staircase fatigue test method is a well-established, but poorly understood probe for determining fatigue strength mean and standard deviation. The sensitivity of results to underlying distributions was studied using Monte Carlo simulation by repeatedly sampling known distributions of hypothetical fatigue strength data with the staircase test method. In this paper, the effects of the underlying distribution on staircase test results are presented with emphasis on original normal, lognormal, Weibull and bimodal data. The results indicate that the mean fatigue strength determined by the staircase testing protocol is largely unaffected by the underlying distribution, but the standard deviation is not. Suggestions for conducting staircase tests are provided.
2005-04-11
Technical Paper
2005-01-0837
B. Yan, C. Kantner, H. Zhu, G. Nadkarni, C. Horvath
Drop tower axial crush testing was performed on hat section samples of various steel grades ranging in minimum tensile strength from 410 MPa to 1300 MPa. It was demonstrated that the energy absorption capability increases with the tensile strength of the steel. However, steels of very high strength, greater than 980 MPa tensile strength, exhibited a greater tendency for weld button pullout or material fracture, and thus limited energy the absorption capability. The effect of the closeout plate and the yield strength of the steel on energy absorption were also investigated. FEA simulations were performed and correlated to the experimental results. A flow stress based material criterion is introduced based on the analytical approach to compare the crush performance of steels.
2005-04-11
Technical Paper
2005-01-0876
Nancy Zeng
The wear test introduced in this paper can be used to determine and rank PV (pressure time velocity) capability of plastic materials for applications where a plastic part is rotating or reciprocating against a metal surface. It provides an accelerated test method to evaluate the wear performance of plastic materials. A single test can provide tribological information at multiple PV conditions. The tribological information obtained from this method includes coefficient of friction, PV (pressure times velocity) limits, and interface temperature profile. This test is currently used by General Motors Corporation to develop plastic materials for transmission thrust washer and dynamic seal applications. The test is running in two sequences (A & B), capable of a PV range from 50,000 psi-ft/min 500,000 psi-ft/min, under dry conditions. The PV steps in sequence A are combinations of high pressure and low velocity - for applications where high loads are expected, such as thrust washers.
2004-03-08
Technical Paper
2004-01-0626
Abolhassan Khosrovaneh, Ravi Pattu, William Schnaidt
This paper is targeted to engineers who are involved in predicting fatigue life using either the strain-life approach or the stress-life approach. However, more emphasis is given to the strain-life approach, which is commonly used for fatigue life analysis in the ground vehicle industry. It attempts to discuss, modify and extend approaches in fatigue analysis, so they are best suited for structural durability engineers. Fatigue analysis requires the use of material fatigue properties, stress or strain results obtained from finite element analyses or measurements, and load data obtained from multi-body dynamic analysis or road load data acquisition. This paper examines the effects of these variables in predicting fatigue life. Various mean stress corrections, along with their advantages and disadvantages are discussed. Different stress/strain combinations such as signed von Mises, and signed Tresca are examined. Also, advanced methods such as Fatemi-Socie and Bannantine are discussed.
2004-03-08
Technical Paper
2004-01-0654
Bob R. Powell, Larry J. Ouimet, John E. Allison, Joy A. Hines, Randy S. Beals, Lawrence Kopka, Peter P. Ried
The US Automotive Materials Partnership (USAMP) and the US Department of Energy launched the Magnesium Powertrain Cast Components Project in 2001 to determine the feasibility and desirability of producing a magnesium-intensive engine; a V6 engine with a magnesium block, bedplate, oil pan, and front cover. In 2003 the Project reached mid-point and accomplished a successful Decision Gate Review for entry into the second half (Phase II) of the Project. Three tasks, comprising Phase I were completed: (1) evaluation of the most promising low-cost, creep-resistant magnesium alloys, (2) design of the engine components using the properties of the optimized alloys and creation of cost model to assess the cost/benefit of the magnesium-intensive engine, and (3) identification and prioritization of scientific research areas deemed by the project team to be critical for the use of magnesium in powertrain applications.
2003-10-27
Technical Paper
2003-01-2753
Timothy M. Boundy
A novel lateral sliding vehicle bucket seat was developed to address consumer needs for improved facile access to third row seats in minivans and sport utility vehicles. The concept provides for a second row bucket seat to slide laterally across a vehicle floor by roller mechanisms that roll across steel rails that transverse the vehicle floor. The system consists of two T-section type steel rails mounted parallel to each other at a distance equal to the seat riser support attachment features. The seat risers contain a roller mechanism that enables contact with the cylindrical portion of the steel rails. Each steel rail contains rectangular openings spaced appropriately to allow the seat latching mechanisms to engage securely. The seat riser supports at the rear include a releasable clamping mechanism hook that engages and disengages into the rectangular openings of the steel rails.
2008-04-14
Journal Article
2008-01-0848
Joseph Z. Wu, Xuru Ding, Zohir Molhem
Abstract This paper suggests a scientific approach to designing conservative tests based on computer simulation of the influence of the sources of variations. The idea is to design the conservative test so that, even in the presence of variation, there is a high probability that a random test will have a better result than the conservative test. Therefore, if the conservative test meets the requirement, one has a scientific reason to believe that any random test would have a high probability of meeting it. This new approach is illustrated for FMVSS301 80 kph 70% rear offset deformable barrier impact.
2008-06-23
Technical Paper
2008-01-1619
Nancy Zeng
A compatibility study was conducted on fluorinated elastomers (FKM and FEPM) in various Automatic Transmission Fluids (ATF). Representative compounds from various FKM families were tested by three major FKM raw material producers - DuPont Performance Elastomers (DPE), Dyneon and Solvay. All involved FKM compounds were tested in a newly released fluid (ATF-A) side-by-side with conventional transmission fluids, at 150°C for various time intervals per ASTM D471. In order to evaluate the fluid compatibility limits, some FKM's were tested as long as 3024 hrs, which is beyond the normal service life of seals. Tensile strength and elongation were monitored as a function of ATF exposure time. The traditional dipolymers and terpolymers showed poor resistance to the new fluid (ATF-A). Both types demonstrated significant decreases in strength and elongation after extended fluid exposure at 150°C.
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