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Many different studies have been performed to understand brake roughness, and in particular how brake rotor Disc Thickness Variation (DTV) is generated. The intent of this paper is to analytically explore through non- linear finite element modeling methods the effects of wheel joint variables on brake rotor mounted Lateral RunOut (LRO). The phenomenon of LRO is believed to be a primary contributor to DTV generation and resulting brake roughness. CAE analyses were conducted in non-linear contact mechanics in which real contacts between components exist. Various joint designs were simulated to compare rotor LRO and coning. Several parameters inherent to the design of wheel joints were varied and studied. A comparative approach was used to develop specific design recommendations for LRO reductions.

An automotive cockpit module is a complex assembly, which consists of components and sub-systems. The critical systems in the cockpit module are the instrument panel (IP), the floor console, and door trim assemblies, which consist of many plastic trims. Stiffness is one of the most important parameters for the plastic trims' design, and it should be optimum to meet all the three functional requirements of safety, vibration and durability. This paper presents how the CAE application and various other techniques are used efficiently to predict the stiffness, and the strength of automotive cockpit systems, which will reduce the product development cycle time and cost. The implicit solver is used for the most of the stiffness analysis, and the explicit techniques are used in highly non-linear situations. This paper also shows the correlations of the CAE results and the physical test results, which will give more confidence in product design and reduce the cost of prototype testing.

The intake and exhaust port design plays a substantial role in performance of combustion systems. The port design determines the volumetric efficiency and in-cylinder charge motion of the spark-ignited engine which influences the thermodynamic properties directly related to the power output, emissions, fuel consumption and NVH properties. Thus intake port has to be appropriately designed to fulfill the required charge motion and high flow performance. While turbulence intensity and air-mixture quality affect dilution tolerance and fuel economy as a result, breathing ability affects wide open throttle performance. Traditional approaches require experimental techniques to reach a target balance between the charge motion and breathing capacity. Such techniques do not necessarily result in an optimized solution.

This paper highlights a simplified CAE model technique, which can simulate and predict door crush strength performance quickly. Such quick models can be used for DFSS and Design change studies. The proposed method suggests an equivalent sub model technique using only the door beam with tuned stiffness end springs to predict FMVSS214S full vehicle crush performance. Such models can be solved in minutes and hence very useful for DFSS studies during product design. The proposed method can be used to finalize door beam design for identical size of vehicle doors to meet required FMVSS214S crush performance. The paper highlights the door beam end springs tuning for identical size of cars and SUVs. Four vehicles were considered for the study. A single spring F-D (force -displacement) is tuned which correlated well for frond door of all the four vehicles. A separate unique spring F-D was needed which correlated well for rear door of all the 4 vehicles.

Nitrocarburizing is an economical surface hardening process and is proposed as an alternative heat treatment method to carbonitriding. The focus of this study is to compare the size and shape distortion and residual stresses resulting from the ferritic nitrocarburizing and gas carbonitriding processes for SAE 1010 plain carbon steel. Gas, ion and vacuum nitrocarburizing processes utilizing different heat treatment temperatures and times were performed to compare the different ferritic nitrocarburizing processes. Navy C-Ring specimens and prototype stamped parts were used to evaluate size and shape distortion. X-ray diffraction techniques were used to determine the residual stresses in the specimens. Overall, the test results indicate that the nitrocarburizing process gives rise to smaller dimensional changes than carbonitriding, and that the size and shape distortion can be considerably reduced by applying appropriate ferritic nitrocarburizing procedures.

Ring gear bolts in differentials are often modified in size to accommodate the additional clamp load that is required due to an increase in torque from a vehicle's powertrain. Depending on a given program several constraints need to be considered. These include cost, validation time, reliability / durability and timing for implementation. In this paper, a Finite Element Analysis (FEA) procedure for analyzing stresses in ring gear bolts within a rear differential assembly is outlined and the computational results are then compared to quasi-static bench test results that were developed to measure bending and tension loads in the ring gear bolts during loading and unloading of the axle pinion. A dynamometer test is then developed to duplicate the failure mode and provide a comparison of the design changes proposed and the expected improvement in durability.

Magnesium alloy extrusions offer potentially more mass saving compared to magnesium castings. One of the tasks in the United States Automotive Materials Partnership (USAMP) ?Magnesium Front End Research and Development? (MFERD) project is to evaluate magnesium extrusion alloys AM30, AZ31 and AZ61 for automotive body applications. Solid and hollow sections were made by lowcost direct extrusion process. Mechanical properties in tension and compression were tested in extrusion, transverse and 45 degree directions. The tensile properties of the extrusion alloys in the extrusion direction are generally higher than those of conventional die cast alloys. However, significant tension-compression asymmetry and plastic anisotropy need to be understood and captured in the component design.

The paper studies the distributions of residual stresses in auto components after induction hardening. Three prototype parts are analyzed in this paper. Firstly, the temperature fields of the analyzed parts are quantitatively simulated during quenching by simulating surface heating to the austenitization temperature of the material. Secondly, the formation and states of the residual stresses are predicted. Therefore the distribution of residual stress is simulated and shows compressive stresses on the surface of components so that the strength can be improved. The simulated results by computer are compared with experimental results. The good comparison indicates that the results obtained by the FEA analysis are reliable. Thus, it can be concluded that the FEA (Finite element analysis) program is effectively developed to simulate heating and quenching processes and residual stresses distribution.

Finite element analysis (FEA) predictions of magnesium beams are compared to load versus displacement test measurements. The beams are made from AM60B die castings, AM30 extrusions and AZ31 sheet. The sheet and die cast beams are built up from two top hat sections joined with toughened epoxy adhesive and structural rivets. LS-DYNA material model MAT_124 predicts the magnesium behavior over a range of strain rates and accommodates different responses in tension and compression. Material test results and FEA experience set the strain to failure limits in the FEA predictions. The boundary conditions in the FEA models closely mimic the loading and constraint conditions in the component testing. Results from quasi-static four-point bend, quasi-static axial compression and high-speed axial compression tests of magnesium beams show the beam's behavior over a range of loadings and test rates. The magnesium beams exhibit significant material cracking and splitting in all the tests.

The focus of this study was to determine the residual stress and retained austenite profiles for carbonitrided and nitrocarburized SAE 1010 plain carbon steel and to relate these profiles to one another and to the distortion resulting from heat treatment. Navy C-ring specimens were used for the purpose of this study and X-ray diffraction techniques were used to measure both residual stress and retained austenite. The findings from this research are then applied to a manufacturing application involving the surface hardening of a thin shelled, plain carbon steel automotive component.

This paper discusses steps for identifying, evaluating and recommending a quantifiable design metric or metrics for Side Airbag (SAB) development. Three functionally related and desirable attributes of a SAB are assumed at the onset, namely, effective SAB coverage, load distribution and efficient energy management at a controlled force level. The third attribute however contradicts the “banana shaped” force-displacement response that characterizes the ineffective energy management reality of most production SAB. In this study, an estimated ATD to SAB interaction energy is used to size and recommend desired force-deformation characteristic of a robust energy management SAB. The study was conducted in the following three phases and corresponding objectives: Phase 1 is a SAB assessment metric identification and estimation, using a uniform block attached to a horizontal impact machine.

Dimensional variation simulation is a computer aided engineering (CAE) method that analyzes the statistical efforts of the component variation to the quality of the final assembly. The traditional tolerance analysis method and commercial CAE software are often based on the assumptions of the rigid part assembly. However, the vehicle functional attributes, such as, ride and handling, NVH, durability and reliability, require understanding the assembly quality under various dynamic conditions while achieving vehicle dimensional clearance targets. This paper presents the methods in evaluating and analyzing the impacts of the assembly variations for the vehicle dynamic performance. Basic linear tolerance stack method and advanced study that applies various CAE tools for the virtual quality analysis in the product and process design will be discussed.

A process for simultaneously optimizing the mechanical performance and minimizing the weight of an automotive body-in-white will be developed herein. The process begins with appropriate load path definition though calculation of an optimized topology. Load paths are then converted to sheet metal, and initial critical cross sections are sized and shaped based on packaging, engineering judgment, and stress and stiffness approximations. As a general direction of design, section requirements are based on an overall vehicle “design for stiffness first” philosophy. Design for impact and durability requirements, which generally call for strength rather than stiffness, are then addressed by judicious application of the most recently developed automotive grade advanced high strength steels. Sheet metal gages, including tailored blanks design, are selected via experience and topometry optimization studies.