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Functioning as an introduction to modern mechanics principles and various applications that deal with the science, mathematics and technical aspects of sheet metal forming, Mechanics Modeling of Sheet Metal Forming details theoretically sound formulations based on principles of continuum mechanics for finite or large deformation, which can then be implemented into simulation codes. The forming processes of complex panels by computer codes, in addition to extensive practical examples, are recreated throughout the many chapters of this book in order to benefit practicing engineers by helping them better understand the output of simulation software.

A diesel fuel and air diffusion flame burner system has been designed for laboratory simulation of diesel exhaust gas. The system consists of mass flow controllers and a fuel pump, and employs several unique design and construction features. It produces particulate emissions with size, number distribution, and morphology similar to diesel exhaust. At the same time, it generates NOx emissions and HC similar to diesel. The system has been applied to test plasma discharges. Different design discharge devices have been tested, with results indicating the importance of testing devices with soot and moisture. Both packed bed reactor and flat plate dielectric barrier discharge systems remove some soot from the gas, but the designs tested are susceptible to soot fouling and related electrical failures. The burner is simple and stable, and is suitable for development and aging of plasma and catalysts systems in the laboratory environment.

A traction test machine, developed for evaluation of traction-CVT fluids for the automotive consortium, USCAR, provides precision traction measurements to stresses up to 4 GPa. The high stress machine, WAMhs, provides an elliptical contact between AISI 52100 steel roller and disc specimens. Machine stiffness and positioning technology offer precision control of linear slip, sideslip and spin. A USCAR traction test methodology includes entrainment velocities from 2 to 10 m/sec and temperatures from -20°C to 140°C. The purpose of the USCAR machine and test methodology is to encourage traction fluid development and to establish a common testing approach for fluid qualification. The machine utilizes custom software, which provides flexibility to conduct comprehensive traction fluid evaluations.

Ford Motor Company is participating in the Department of Energy's (DOE) Ultra-Clean Transportation Fuels Program with the goal to explore the development of innovative emission control systems for advanced compression-ignition direct-injection (CIDI) transportation engines. CIDI (or diesel) engines have the advantages of a potential 40% fuel economy improvement and 20% less CO2 emissions than current gasoline counterparts. To support this goal, Ford plans to demonstrate an exhaust emission control system that provides high efficiency particulate matter (PM) and NOx reduction. Very low sulfur diesel fuel will be used to enable low PM emissions, reduce the fuel economy penalty associated with the emission control system, and increase the long-term durability of the system. The end result will allow vehicles with CIDI engines to be Tier II emissions certified at a minimum cost to the consumer.

In order to assess the amount of airborne particulate matter (PM) attributable to vehicle disk brakes, a system was devised for collecting brake wear debris on a laboratory brake dynamometer. The brake dynamometer test hardware was enclosed and vented through a duct in which the airflow was controlled to ensure isokinetic sampling. Two brake dynamometer simulations were implemented: urban driving (low velocity, low g) and the Auto Motor und Sport (AMS, high velocity, high g). These test procedures were performed repeatedly on the brake system hardware of vehicles utilizing three different friction material types: low-metallic, semi-metallic, and non-asbestos organic (NAO). Airborne brake wear was collected on filters and via other airborne PM sampling techniques. Larger, non-airborne wear debris was collected from the wheel, below the brake, and brushed off the hardware. Considering the effect of the wheel, 50-70% of the collected wear debris was airborne PM.

Diesel vehicles have significant advantages over their gasoline counterparts including a more efficient engine, higher fuel economy, and lower emissions of HC, CO, and CO2. However, NOx control is more difficult on a diesel because of the high O2 concentration in the exhaust, making conventional three-way catalysts ineffective. The most promising technology for continuous NOx reduction onboard diesel vehicles is Selective Catalytic Reduction (SCR) using aqueous urea. Recent work with urea SCR has involved aftertreatment for the 1.2L DIATA common-rail diesel engine. This engine was used in Ford's hybrid-electric vehicle, the Prodigy, which was developed under the PNGV (Partnership for a New Generation of Vehicles) program. An emission control system consisting of a diesel particulate filter followed by an underbody SCR system was used successfully to meet ULEV emission standards (0.2 g/mi NOx, 0.04 g/mi particulate matter (PM)).

In this paper, the formability of AA5754 aluminum laser-welded blanks produced by Nd:YAG laser welding is investigated under biaxial straining conditions. The mechanical behavior of the laser-welded blanks is first examined by uniaxial tensile tests conducted with the weld line perpendicular to the tensile axis. Shear failure in the weld metal is observed in the experiments. Finite element simulations under generalized plane strain conditions are then conducted in order to further understand the effects of weld geometry and strength on the shear failure and formability of these welded blanks. The strain histories of the material elements in the weld metal obtained from finite element computations are finally used in a theoretical failure analysis based on the material imperfection approach to predict the failure strains for the laser-welded blanks under biaxial straining conditions.

Nonthermal plasma discharges in combination with catalysts are being developed for diesel aftertreatment. NOx conversion has been shown over several different catalyst materials. Particulate removal has also been demonstrated. The gas phase chemistry of the plasma discharge is described. The plasma is oxidative. NO is converted to NO2, CH3ONO2 and HNO3. Hydrocarbons are partially oxidized resulting in aldehydes and CO along with various organic species. Soot will oxidize if it is held in the plasma. When HC is present, SO2 is not converted to sulfates. Suitable plasma-catalysts can achieve NOx conversion over 70%, with a wider effective temperature range than non-plasma catalysts. NOx conversion requires HC and O2. Electrical power consumption and required exhaust HC levels increase fuel consumption by several percent. A plasma catalyst system has demonstrated over 90% particulate removal in vehicle exhaust.

Previously reported experiments revealed the presence of a small number of clusters or very small particles in the effluent of a nonthermal plasma reactor when treating a simulated engine exhaust mixture. These clusters are smaller than 7 nm. The quantity of clusters is orders of magnitude smaller than the particulate diesel or gasoline engine exhaust typically contains. In this report, we describe further experiments designed to determine the chemical composition of the clusters. Clusters were collected on the surface of a silicon substrate by exposing it to the effluent flow for extended time periods. The resulting deposits were analyzed by high mass resolution SIMS and by XPS. The SIMS analysis reveals NH4+, CH6N+, SO-, SO2-, SO3- and HSO4- ions. XPS reveals the presence of N and S at binding energies consistent with that of ammonium sulfate.

The direct injection gasoline spray-wall interaction was characterized inside a heated pressurized chamber using various visualization techniques, including high-speed laser-sheet macroscopic and microscopic movies up to 25,000 frames per second, shadowgraph, and doublespark particle image velocimetry. Two hollow cone high-pressure swirl injectors having different cone angles were used to inject gasoline onto a heated plate at two different impingement angles. Based on the visualization results, the overall transient spray impingement structure, fuel film formation, and preliminary droplet size and velocity were analyzed. The results show that upward spray vortex inside the spray is more obvious at elevated temperature condition, particularly for the wide-cone-angle injector, due to the vaporization of small droplets and decreased air density. Film build-up on the surface is clearly observed at both ambient and elevated temperature, especially for narrow cone spray.

This paper is concerned with the use of solid elements in sheet metal forming simulation, particularly springback prediction for flanging when the flanging radii are comparable with the metal thickness. It is demonstrated that appropriate solid elements must be used instead of shell elements in order to obtain adequate results. Numerical difficulties associated with development of suitable solid elements are discussed in detail, with emphasis on the volumetric locking and transverse shear locking phenomena respectively. The transverse shear locking arises from the incompatible deformation modes when the element is used for thin structure bending analysis. A four point bending testing problem is used to study the performances of different solid elements. A locking-free solid element based on assumed strain formulation is developed in Ford in-house program MTLFRM for accurate springback prediction, and a flanging example is given to demonstrate its application.

Thermally-sprayed, composite coatings have been developed and sprayed on aluminum engine heads to replace powdered metal valve seat inserts. The process uses a conventional two-wire arc (TWA) gun with nickel and iron-based wire feedstocks. A unique surface preparation technique was developed to assure excellent coating adhesion. A composite Fe/Fe3O4/Ni/NiO/CrO coating was dynamometer tested using a single-cylinder Rotax engine, and showed improved wear performance over a conventional powdered-metal insert. Details of surface preparation, coating development, tribological properties and engine testing are described in this work.

The present research is concerned with the quality of the shearing process, which is an integral part of automotive vehicle body stamping. Experiments were done to analyse the influence of the gap between the cutting edges and the geometry of the cutting blades, on the quality of the sheared surface. Experimental results are presented as microstructures of polished samples. To predict the quality of sheared surfaces, a numerical code based on solid mechanics equations, elastoplastic flow theory and cummulative theory of damages was created.

The requirement of reducing HC emissions during cold start and improving transient performance has prompted a study of the fuel injection process. Port-fuel-injection with the Intake-valve open using small droplets is a potentially feasible option to achieve the goals. To gain a better understanding of the injection process, the effects of droplet size, injection timing, and coolant temperature on the total and speciated HC emissions were tested In a Single-cylinder engine. It was found that droplet size plays an important role in the total HC emission increase during open-valve injection, especially with cold operation. Large droplets (300 μm SMD) produced a substantial HC increase while small droplets (14 μm SMD) produced no observable increase. Increase In the total HC emissions was always accompanied by an increase in the heavy fuel components in the exhaust gases.