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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.

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.

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.

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.

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.

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.

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.

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.

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.

Traditional methods used to produce a die set (from developing initial machining cutter paths through finalized die tryout to produce a part that meets design intent) begin with draw simulation and development. It is here, traditionally, that scientific evaluation of actual metal stretch and theoretical ideals end. In past programs, a designed part would be simulated for stretch and a development model created to include various die compensations (i.e. springback, overcrown, etc.) based on past experience for area and amount. At this point, the die is cut and undergoes a metamorphosis through die tryout to finally produce a quality part. This is currently an open loop system. This paper will focus on the differences in the predicted way the die should look and the actual outcome (after part buyoff).

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.

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.

The overall program objectives were three fold: assess the benefits and limitations of oxygenated diesel fuels on engine performance and emissions identify oxygenates most suitable for potential use in future diesel formulations based on physico-chemical properties (e.g. flash point), toxicity, biodegradability and estimated cost of production perform limited emissions and performance testing of the oxygenated diesel blends select at least two oxygenated compounds for advanced engine testing In Part 1 of this program which is described in this paper, an extensive literature review was conducted to identify potential oxygenates for blending into diesel fuels. As many as 71 oxygenates were identified for the initial screening process. Based on a set of physical and chemical properties, a screening methodology was developed to select the 8 oxygenates that will be eligible for engine testing.

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.

This paper presents the results of optimization study for sunroof buffeting reduction using CFD technology. For an early prototype vehicle as a baseline model in this study a high level of sunroof buffeting 133dB has been found. The CFD simulation shows that the buffeting noise can be reduced by installing a wind deflector at its optimal angle 40 degrees from the upward vertical line. Further optimization study demonstrates that the buffeting peak SPL can be reduced to 97dB if the sunroof glass moves to its optimal position, 50% of the total length of the sunroof from the front edge. For any other vehicles, the optimization procedure is the same to get the optimal parameters. On the other hand, however, this optimization study is only based on fluid dynamics principle without considering manufacturability, styling, cost, etc. Further work is needed to utilize the results in the production design.