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The destruction of low concentrations (<600 ppm) of nitric oxide using a low-temperature, dielectric barrier/packed-bed corona reactor has been studied. We compare the chemistry and energy efficiencies observed using various packing materials in warm moist air under oxidative (lean-burn) conditions. Measurements of NO and NOx removal in the effluent gas were made as a function of energy dissipated in the reactor. Changes in the observed fate of NO as a function of the packing material are discussed.

A new electrode holder designed for resistance spot welding of aluminum twists the electrode while it contacts the workpiece. The limited rotation grinds the electrode tip into the surface of the workpiece, abrading it and obtaining good electrical contact. The improved electrical contact results in less heat generation at the tip/workpiece interface, which leads to longer tip life and more consistent welds. Test results show that tip life increases nearly 500 percent when using a twisting electrode holder. In addition, weld quality is improved and more consistent welds are produced than with standard spot welding practice. By using these new electrode holders, automobile manufacturers will decrease the downtime associated with replacing electrode tips and reduce the number of assemblies that have to be torn apart for quality control inspection.

The hole stretchability of two Aluminum Alloys (AA6111 and AA6022) are studied by using a two stages integrated finite element framework where the edge geometry and edge damages from the hole piercing processes were considered in the subsequent hole expansion processes. Experimentally it has been found that AA6022 has higher hole expansion ratios than those of AA6111. This observation has been nicely captured by finite element simulations. The main cause of differences have been identified to the volume fractions of the random distributed second phase hard particles which play a critical role in determining the fracture strains of the materials.

Automobile body and truck cab structures are composed primarily of stampings formed from monolithic and constant gage blanks. Cost and weight penalties can arise when strength or other requirements in one small area of the part leads to the use of a material or gage that is overmatched to the needs of the rest of the stamping. Tailor Welded Blanks (TWBs) are hybrid sheet products composed of either different materials or different thickness sheets that are joined together, then subjected to a stamping operation to create a formed assembly. The strategy is employed generally to save weight and material costs in the formed assembly by placing higher strength or thicker sections only where needed. The forming or stamping process requires the joint to be severely deformed along with the parent sheets. Aluminum TWBs for automotive applications are particularly problematic because of the low formability of aluminum weld metal.

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.

The aluminum alloy 2036 is presently being used in the production of automotive body panels. In the study presented, specimens of 2036-T4 with varying crystallographic textures were subjected to tensile testing and limiting dome height (LDH) evaluations in an effort to gauge the effect of texture on formability and stamping performance. To describe the texture, relative magnitudes of ideal texture components were derived from the orientation distribution function. Finite element analysis was used to study the effect of anisotropic properties due to texture on thinning in the LDH test. The impact of textural character on formability is discussed.

One joining technique that is receiving increased attention is mechanical fastening with a steel self-piercing rivet. The use of steel rivets in direct contact with aluminum components raises questions concerning galvanic corrosion. To determine if a corrosion problem exists, aluminum samples were joined by two processes--resistance spot welding and steel self-piercing rivets. Replicate samples using two aluminum alloys were tested for 90 days by alternate immersion in 3.5% NaCl water solution. After alternate immersion exposure, the integrity of the joint was evaluated by shear testing. Joint shear strengths and the metallographic corrosion evaluations are presented in this paper.

Sustained NOx reduction at low temperatures, especially in the 150-200 °C range, shares some similarities with the more commonly discussed cold-start challenge, however, poses a number of additional and distinct technical problems. In this project, we set a bold target of achieving and maintaining 90% NOx conversion at the SCR catalyst inlet temperature of 150 °C. This project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015 and completed in 2017.

We developed a non-destructive and non-contact method for measuring stress at the mid-plane of tempered glass plates that uses Bragg scattering from a pair of thermal gratings. These gratings are formed by 1064 nm beams from a seeded Nd:YAG laser and we measure the polarization state of light from a 532 nm beam that scatters from both these thermal gratings. The change in polarization of the doubly scattered light with separation between the two gratings allows measurement of the in-plane stress. Stress measurements are reported.

The history of the development of sheet aluminum wheels, including alloy selection, properties, and tests are discussed. A number of alloys were considered for wheel application. The strain hardening characteristics, the excellent corrosion resistance and other property criteria led to the selection of 5454 as the sheet aluminum wheel alloy

Recent trends in the automotive industry toward improving fuel economy have led to the conversion of many steel applications to aluminum. The use of aluminum reduces vehicle weight while allowing the automaker to continue to use traditional fabricating methods. The primary joining technique used for steel sheet components has been resistance spot welding. While this technique is currently used to join many aluminum components, automakers are reluctant to specify this joining technique due to capital equipment cost, electrode tip life, or reliability concerns. Several alternate joining techniques have been investigated and used. These include adhesive bonding, weld bonding, resistance welding with arc cleaning (1, 2)*, GMA spot welding, clinching, and riveting. Recently, a method of riveting components without prepunching or pre-drilling holes has generated a large amount of interest. This paper is a review of this riveting technique.

The catalytic activity of selected materials (BaY and NaY zeolites, and γ-alumina) for selective NOx reduction in combination with a non-thermal plasma was investigated. Our studies suggest that aldehydes, formed during the plasma treatment of simulated diesel exhaust, are the important species for the reduction of NOx to N2. Indeed, all materials that are active in plasma-assisted catalysis were found to be very effective for the thermal reduction of NOx in the presence of aldehydes. For example, the thermal catalytic activity of a BaY zeolite with aldehydes gives 80-90% NOx removal at 250°C with 200ppm NOx at the inlet and a VHSV=12,000 h-1. The hydrocarbon reductants, n-octane and 1-propyl alcohol, have also shown high thermal catalytic activity for NOx removal over BaY, NaY and γ-alumina.

Mixing controlled compression ignition, i.e., diesel engines are efficient and are likely to continue to be the primary means for movement of goods for many years. Low-net-carbon biofuels have the potential to significantly reduce the carbon footprint of diesel combustion and could have advantageous properties for combustion, such as high cetane number and reduced engine-out particle and NOx emissions. We developed a list of over 400 potential biomass-derived diesel blendstocks and populated a database with the properties and characteristics of these materials. Fuel properties were determined by measurement, model prediction, or literature review. Screening criteria were developed to determine if a blendstock met the basic requirements for handling in the diesel distribution system and use as a blend with conventional diesel. Criteria included cetane number ≥40, flashpoint ≥52°C, and boiling point or T90 ≤338°C.

The Reynolds’ 390 engine technology eliminates the need for iron bore liners in aluminum engines. This allows casting of the cylinder block and bores as an integral unit. The technology is a three-part system consisting of the hypereutectic 390 aluminum-silicon alloy, compatible pistons and a special cylinder bore finish. When properly applied, it can produce a lightweight, strong, compact and relatively low-cost aluminum engine block.

A noticeable degree of inconsistent forming behaviors has been observed for the 1st generation advanced high strength steels (AHSS) in production, and they appear to be associated with the inherent microstructural-level inhomogeneities for various AHSS. This indicates that the basic material property requirements and screening methods currently used for the mild steels and high strength low alloys (HSLA) are no longer sufficient for qualifying today's AHSS. In order to establish more relevant material acceptance criteria for AHSS, the fundamental understandings on key mechanical properties and microstructural features influencing the local formability of AHSS need to be developed. For this purpose, in this study, DP980 was selected as model steels and eight different types of DP980 sheet steels were acquired from various steel suppliers.

Tailored blanks have been produced by a variety of welding processes. Currently, laser welding and mash seam welding are commonly used to produce steel blanks for automotive stampings. Because of the high electrical and thermal conductivity of aluminum, mash seam welding is generally not suitable for this application. Laser welding is currently in the developmental stage for welding aluminum. Reynolds Metals Company is investigating another existing welding technology -- Gas Tungsten Arc Welding (GTAW)--for welding of aluminum tailored blanks. Using the GTAW process, production weld speeds approximating those of laser systems can be obtained. Additionally, good control of weld geometry and quality can be easily attained. This study focuses on GTA welding process parameters for joining various alloys, tempers, and thickness of aluminum. Additionally, performance of welded joints in terms of strength, ductility, and formability are discussed.

This paper describes a method for predicting structural failure probabilities for automotive windshields. The predictive model is supported by the data from strength tests performed on specimens of automotive glass. Evaluations of stresses can be based on finite element calculations, or measurements of the residual stresses that arise from fabrication. Failure probabilities for each subregion of a windshield are estimated from the local state of stress, the surface area or length (for edge elements) of the subregion, and statistical distributions of glass strengths. Example calculations are presented that show the relative contributions of edge stresses, surface stresses and residual stresses to calculated failure probabilities.

In this paper, a three-dimensional (3D) microstructure-based finite element modeling method (i.e., extrinsic modeling method) is developed, which can be used in examining the effects of porosity on the ductility/fracture of Mg castings. For this purpose, AM60 Mg tensile samples were generated under high-pressure die-casting in a specially-designed mold. Before the tensile test, the samples were CT-scanned to obtain the pore distributions within the samples. 3D microstructure-based finite element models were then developed based on the obtained actual pore distributions of the gauge area. The input properties for the matrix material were determined by fitting the simulation result to the experimental result of a selected sample, and then used for all the other samples’ simulation. The results show that the ductility and fracture locations predicted from simulations agree well with the experimental results.

This paper describes two independent studies on γ-alumina as a plasma-activated catalyst. γ-alumina (2.5 - 4.3 wt%) was coated onto the surface of mesoporous silica to determine the importance of aluminum surface coordination on NOx conversion in conjunction with nonthermal plasma. Results indicate that the presence of 5- and 6- fold aluminum coordination sites in γ-alumina could be a significant factor in the NOx reduction process. A second study examined the effect of changing the reducing agent on NOx conversion. Several hydrocarbons were examined including propene, propane, isooctane, methanol, and acetaldehyde. It is demonstrated that methanol was the most effective reducing agent of those tested for a plasma-facilitated reaction over γ-alumina.

This paper describes the application of pore-scale filtration simulations to the advanced ceramic material (ACM) developed for use in advanced diesel particulate filters. The application required the generation of a three-dimensional substrate geometry to provide the boundary conditions for the flow model. An innovative stochastic modeling technique was applied matching chord length distribution and the porosity profile of the material. Additional experimental validation was provided by the single-channel experimental apparatus. Results show that the stochastic reconstruction techniques provide flexibility and appropriate accuracy for the modeling efforts. Early investigation efforts imply that needle length may provide a mechanism for adjusting performance of the ACM for diesel particulate filter (DPF) applications. New techniques have been developed to visualize soot deposition in both traditional and new DPF substrate materials.