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This paper investigates the potential of using FEA poro-elastic Biot elements for the modeling carpet-like trim systems in a simplified setup. A comparison between FEA computations and experiments is presented for two layer (mass-spring) trim systems placed on a test-rig consisting in a 510×354×1.6 mm flat steel plate clamped in a stiff frame excited at its base. Results are presented for a given heavy layer with two different poro-elastic materials: one foam and one fibrous material. The investigations included accelerometer measurements on the steel plate, laser-doppler vibrometer scans of the heavy layer surface, sound pressure measurements in free field at a distance of 1 meter above the plate, as well as sound pressure in a closed rectangular concrete-walled cavity (0.5×0.6×0.7 m) put on top of the test-rig. Computations were carried out using a commercial FEA software implementing the Biot theory for poro-elastic media.

In this paper, responses from a vehicle's suspension, chassis and body, are used to demonstrate a methodology to optimize physical test results. It is well known that there is a variability effect due to an increase of wheel unsprung mass (due to loads measurement fixturing), tire pressure, speed, etc. This paper quantifies loading variability due to Wheel Force Transducer (WFT) unsprung mass by using a rainflow cycle counting domain. Also, presents a proving ground-to-test correlation study and the data reduction techniques that are used in road simulation test development to identify the most nominal road load measurement. Fundamental technical information and analytical methodology useful in overall vehicle durability testing are discussed. Durability testing in a laboratory is designed to correlate fatigue damage rig to road. A Proving Ground (PG) loading history is often acquired by running an instrumented vehicle over one or more PG events with various drivers.

The LEV II and SULEV/PZEV emission standards legislated by the US EPA and the Californian ARB will require continuous reduction in the vehicles' emission over the next several years. Similar requirements are under discussion in the European Union (EU) in the EU Stage V program. These future emission standards will require a more efficient after treatment device that exhibits high activity and excellent durabilty over an extended lifetime. The present study summarizes the findings of a joint development program targeting such demanding future emission challenges, which can only be met by a close and intensive co-operation of the individual expert teams. The use of active systems, e.g. HC-adsorber or electrically heated light-off catalysts, was not considered in this study. The following parameters were investigated in detail: The development of a high-tech three-way catalyst technology is described being tailored for applications on ultra thin wall ceramic substrates (UTWS).

In the automotive industry, the model-based approach is increasingly establishing itself as a standard paradigm for developing control unit software. Just as code reviews are widespread in classical software development as a quality assurance measure, models also have to undergo a stringent review procedure – particularly if they serve as a starting point for automatic implementation by code generators. In addition to these model reviews, the generated production code is reviewed later in the development process by performing auto code reviews. This article will present procedures for and give an account of experiences with model and code reviews which have been adapted to the model-based development process.

An assessment of stamped part quality and launch readiness occurs at many intervals. This paper will focus on dimensional control activities that take place after Stamping Dies are constructed, but prior to producing the stamped parts. Die certification and die repeatability measurements have been performed at DaimlerChrysler and the results are documented. This die certification process provides an opportunity to uncover and resolve die machining issues with respect to the part math model or pre-engineered compensation model prior to producing parts. Additionally, the die repeatability process is performed to determine the ability of the die gaging to locate the incoming in-process material consistently. This paper will explain the die certification and die repeatability processes and share what we have learned. It will describe the processes, the tools, the participants, the sites, the benefits, and the measurement equipment.

Circle grid analysis is often used throughout the different stages of stamping tool development to locate and correct critical strains in stampings based on the forming limit diagram of the sheet steel. Understanding the interaction among the grid, tooling, and sheet steel to be formed is important in making a reliable part strain analysis. It has been observed that a given sheet steel may produce acceptable parts in soft tool, yet split or neck in the hard tool/production stage even with similar tooling geometry. Four different automotive sheet steels and five different fixed bead material types were selected for draw bead simulator testing to determine the effect of electro-etching of the grid on frictional characteristics. Of the sheet steels examined - uncoated cold roll, hot dip galvanized, hot dip galvanneal, and electrogalvanized, circle gridding tended to increase the coefficient of friction for all but hot dip galvanneal, where the friction decreased with gridding.

Hot Isostatic Pressing (HIP) has been routinely used to densify castings for aerospace and medical applications for over 30 years. While HIP is widely known to improve the toughness and fatigue life of castings through the healing of internal porosity, it has been perceived as too expensive for most cast aluminum alloys for automotive applications. Recent developments suggest that the cost effectiveness of certain special HIP processes should be revisited due to reductions in process cost and improvements in throughput. This paper will evaluate the Densal® II process applied to a front aluminum steering knuckle. Two casting processes representing differing levels of relative cost and quality were evaluated. The first was Alcoa's VRC/PRC process, a metal mold process with bottom fill, evacuation before fill and pressurization after fill. This is considered to be a premium quality, but higher cost casting process that is already qualified for this application.

This paper describes work supporting the development of a new Diesel particulate trap system for heavy duty vehicles based on porous sintered metal materials that exhibit interesting characteristics with respect to ash tolerance. Experimental data characterizing the material (permeability, soot and ash deposit properties) are obtained in a dedicated experimental setup in the side-stream of a modern Diesel engine as well as in an accelerated ash loading rig. System level simulations coupling the new media characteristics to 3-D CFD software for the optimization of complete filter systems are then performed and comparative assessment results of example designs are given.

Strain rate sensitivity is an important material property in the formability of sheet metal. In this study, strain rate sensitivity is evaluated for several different grades of steel. Strain rate sensitivity varies from 0.01 to 0.022 for the steels tested. It was found that formable steels such as IF and AKDQ steels have both high n-value (strain hardening) and m-value (strain rate sensitivity). Positive strain rate sensitivity results in a significant increase in the yield strength and tensile strength at higher strain rates. The n-value decreases with strain rate for all of the steels. The total elongation decreases slightly with strain rate for the lower strength steels but is constant or even increases slightly with strain rate for high strength steels. For a typical AKDQ steel, the increase in yield strength can be as high as 43% for an increase in strain rate from 0.002 /s to 2.0 /s.

New design techniques will require that more be known about the response of metals to various service conditions. This paper discusses experimental work which was done to define the response of several hot worked metals to several deformation rates. The results show that ferrous materials with low alloy contents are very strain rate sensitive under the conditions of testing, regardless of the static strength level. These materials exhibit strength and absorbed-energy increases and uniform elongation losses with strain rate increases. A 6061-T6 aluminum alloy tested for comparison showed no strain rate sensitivity over the range of testing conditions. In a practical sense, ferrous alloys will be stronger at high loading rates than expected from ordinary mechanical property measurements. This can be an important advantage when considering dent and crash resistance.

In recent years, strict weight reduction targets have pushed auto manufacturers to use lighter gauge sheet steels in all areas of the vehicle including exterior body panels. As sheet metal thicknesses are reduced, dentability of body panels becomes of increasing concern. Thus, the goal becomes one of reducing sheet metal thickness while maintaining acceptable dent resistance. Most prior work in this area has focused on quasi-static loading conditions. In this study, both quasi-static and dynamic dent tests are evaluated. Fully assembled doors made from mild, medium strength bake hardenable and non-bake hardenable steels are examined. The quasi-static dent test is run at a test speed of 0.1 m/minute while the dynamic dent test is run at a test speed of 26.8 m/minute. Dynamic dent testing is of interest because it more closely approximates real life denting conditions such as in-plant handling and transit damage, and parking lot damage from car door and shopping cart impact.

Traditionally, high-strength low-alloy (HSLA) steel is used for automotive vehicle weight reduction in the North American automotive industry. Dual phase (DP) high strength steel has gained great attention because it provides a combination of high strength and good formability. The main advantage of DP steel is the high ratio of tensile strength to yield strength, which provides more flexibility in stamping and higher energy absorption in a component crush event. This study compares the performances of DP and HSLA steel grades in stamping processes and component crush events, as shown in a typical automotive unibody inner rail. Simulation results show that DP steel offers more uniform strain distribution, improved formability, and better crush performance than conventional HSLA steel.

A Draw Bead Simulator (DBS), with modified draw beads, was employed in this study to understand the springback behavior of sheet metal subjected to multiple bending-unbending cycles. The investigations were carried out in both the rolling and the transverse rolling directions on four types of materials: Electro-Galvanized DQ steel, light and heavy gauge Hot-Dip Galvanealed High Strength Steels, and Aluminum alloy AL6111. The sheet geometries, thickness strains, pulling forces and clamping forces were measured and analyzed for the purpose of establishing a benchmark database for numerical predictions of springback. The results indicate that the springback curvature changes dramatically with the die holding force. The conditions at which the springback is minimized was observed and found to depend on the material properties and the sheet thickness. Analysis with an implicit FEM showed that the predicted and the experimental results are in very good agreement.

Silicon Carbide (SiC) based high temperature semiconductor gas sensors were tested for potential applications in the closed-loop control of NOx storage catalytic converters. The exhaust gas composition behind a storage catalyst was simulated by synthetic gas mixtures supplied from a gas blending manifold. In lean oxidizing ambients the sensors produced signals opposite in sign upon the appearance of NOx on the one hand and mixtures of HC and CO on the other hand. Transient gas measurements revealed response times ranging between several milliseconds for HC and several seconds for NOx. These features render SiC based sensors potentially useful for the control of NOx storage catalytic converters.

The staircase fatigue testing method is a recognized method for determining the fatigue limit of powertrain components. The purpose of this paper is to improve upon existing standards by adding common practices that will ensure a higher degree of statistical accuracy in the data. This includes specifying appropriate sample sizes, stress increments and initial load conditions, as well as making suggestions for appropriate methods of analyzing the data. Two methods (Dixon and Mood method and probit analysis method) are selected and compared in terms of relative percent difference on four parameters (mean, standard deviation, B10 fatigue strength and B50 fatigue strength). The staircase data are obtained by simulations from normal and lognormal fatigue limit distributions.

Sheet metal stamping involves a system of complex tribological (friction, lubrication, and wear), heat transfer, and material strain interactions. Accurate coefficient of friction, strain, and lubrication regime data is required to allow proper modeling of the various sheet stamping processes. In addition, non-intrusive means of monitoring the coefficient of friction in production stamping operations would be of assistance for efficiently maintaining proper stamping quality and to indicate when adjustments to the various stamping parameters, including maintenance, would be advantageous. One of the key sub-systems of the sheet metal stamping process is the draw bead. This paper presents an investigation of the tribology of the draw bead using a Draw Bead Simulator (DBS) Machine and automotive zinc-coated sheet steels. The investigation and findings include: 1) A new, non-intrusive method of measuring the surface temperature of the sheet steel as it passes through the draw bead.

The influence of adsorption and desorption processes on the non-thermal plasma enhanced catalytic reduction of NOx on NaZSM5- and Al2O3-based lean-NOx catalysts (Pt-NH4ZSM5, Cu-NaZSM5, Fe-NaZSM5, Pt-Al2O3, Pd-Al2O3, CuO-Al2O3, Ag-Al2O3) was investigated by temperature programmed reaction experiments in the temperature range from 100 °C to 600 °C. Dodecane was used as a reducing agent. Strong HC adsorption- and desorption effects were observed on the zeolite catalysts, which were not influenced by plasma-pretreatment. Adsorption of NO2 and desorption of NO occurred on Al2O3-based catalysts. By plasma-pretreatment adsorption of NO2 was induced at low temperatures. NOx-reduction rates of the catalysts Cu-NaZSM5, Fe-NaZSM5, and the Ag-Al2O3 were increased substantially by plasma-pretreatment. Both plasma-induced and catalytic oxidation of HCs were limiting factors of the NOx-reduction obtained on these catalysts.

Even with the rapidly evolving computational tools available today, suspension design remains very much a black art. This is especially true with respect to road cars because there are so many competing design objectives. In a racecar some of these objectives may be neglected. Even still, just concentrating on maximizing road-holding capability remains a formidable task. This paper outlines a procedure for establishing suspension parameters, and includes a computational example that entails spring, damper, and anti-roll bar specification. The procedure is unique in that it not only covers the prerequisite vehicle dynamic equations, but also outlines the process that sequences the design evolution. The racecar design covered in the example is typical of a growing number of small open wheel formula racecars, built specifically for American autocrossing and British hillclimbs.

Vehicle weight reduction, reduced costs and improved safety performance are the main driving forces behind material selection for automotive applications. High strength steels (HSS) have demonstrated their ability to meet these demands and consequently have been the fastest growing light-weighting material in vehicle structures for the past decade. The evolution in steel technology in recent years has produced new grades of highly formable, advanced high strength steel (AHSS) grades that will continue to meet these automotive demands into the next decade. This paper describes how the remarkable combination of formability, strength, ductility, durability, strain-rate sensitivity and strain hardening characteristics of the AHSS grades enable affordable weight reduction while improving crash safety.

Mercedes-Benz at DaimlerChrysler has been developing and applying Life-Cycle-Engineering (LCE) and Life-Cycle-Assessment (LCA) since almost 10 years. Extensive experience and know-how has been gained by two complete car LCAs and more than 100 LCAs for parts. According to our experience LCA/LCE is most effectively and efficiently used to support the development of new products. One of DaimlerChrysler's Environmental Guidelines includes a statement, that our approach to environmentally acceptable design covers the entire product spectrum of the DaimlerChrysler Group, taking into account the product life cycle from design through disposal or recycling. The organisation of environmental management at DaimlerChrysler has a distinct structure of tasks: the central Environmental Protection Division coordinates all organisation/ plant related aspects, while all product related aspects are the responsibility of the divisonal business units.