Search Results

Described in this paper is a component test methodology to evaluate the door trim armrest performance in an Insurance Institute for Highway Safety (IIHS) side impact test and to predict the SID-IIs abdomen injury metrics (rib deflection, deflection rate and V*C). The test methodology consisted of a sub-assembly of two SID-IIs abdomen ribs with spine box, mounted on a linear bearing and allowed to translate in the direction of impact. The spine box with the assembly of two abdominal ribs was rigidly attached to the sliding test fixture, and is stationary at the start of the test. The door trim armrest was mounted on the impactor, which was prescribed the door velocity profile obtained from full-vehicle test. The location and orientation of the armrest relative to the dummy abdomen ribs was maintained the same as in the full-vehicle test.

As part of an ongoing technical collaboration between Ford and Rouge Steel Company, a comprehensive study of door slam event was undertaken. The experimental phase of the project involved measurements of accelerations at eight locations on the outer panel and strains on six locations of the inner panel. Although slam tests were conducted with window up and window down, results of only one test is presented in this paper. The CAE phase of the project involved the development of suitable “math” model of the door assembly and analysis methodology to capture the dynamics of the event. The predictability of the CAE method is examined through detailed comparison of accelerations and strains. While excellent agreement between CAE and test results of accelerations on the outer panel is obtained, the analysis predicts higher strains on the inner panel than the test. In addition, the tendency of outer panel to elastically buckle is examined.

There are several reasons why it can be daunting to apply Six Sigma to product creation. Foremost among them, the functional performance of new technologies is unknown prior to starting a project. Although, Design For Six Sigma (DFSS) was developed to overcome this difficulty, a lack of applicable in-class case studies makes it challenging to train the product creation community. The current paper describes an in-class project which illustrates how Six Sigma is applied to a simulated product creation environment. A toy construction set (TCS) project is used to instruct students how to meet customer expectations without violating cost, packaging volume and design-complexity constraints.

Adhesive bonding technology is playing an increasingly important role in automotive industry. Ultrasonic evaluation of adhesive joints of metal sheets is a challenging problem in Non-Destructive Testing due to the large acoustic impedance mismatch between metal and adhesive, variability in the thickness of metal and adhesive layers, as well as variability in joint geometry. In this paper, we present the results from a matrix array of small flat ultrasonic transducers for evaluation of adhesively bonded joints in both laboratory and production environments. The reverberating waveforms recorded by the array elements are processed to obtain an informative parameter, whose two-dimensional distribution can be presented as a C-scan. Energy of the reflected waveform, normalized with respect to the energy obtained from an area with no adhesive, is a robust parameter for discriminating "adhesive/no-adhesive" regions.

The Snook tables (Liberty Mutual Tables) are a collection of data sets compiled from studies based on a psychophysical approach to material-handling tasks. These tables are used to determine safe loads for lifting, lowering, carrying pulling, and pushing. The tables take into account different population percentiles, gender, and frequency of activity. However, while using these tables to analyze a work place, Ergonomists often have to select from discrete data points closest to the actual work place parameters thereby reducing accuracy of results. To compound the problem further, multiple interrelated variables are involved, making it difficult to analyze parameters intuitively. For example, it can be difficult to answer questions such as, does reducing the lifting height lower the recommended lifting weight, if the lifting distance is increased? To resolve such issues, this paper presents a new methodology for implementing the Snook tables using multi variable regression.

An automobile seat’s thermal performance can be challenging to quantify since it requires comprehensive human subject testing. Seat manufacturers must rely on subjective ratings to understand how the construction of a seat and its underlying heating and cooling technology may compare to other seats. Other factors may influence seat ratings published by global marketing information services companies (e.g., JD Power and Associates). In particular, occupants may be biased by the vehicle class in which a seat is installed and by how much the contribution of a specific vehicle’s HVAC system performance affects the perception of seat thermal comfort. Therefore, there is a need for an objective testing methodology that does not rely on human participants but is still capable of producing a thermal performance rating in terms of established thermal comfort scales.

SiC devices have inherent fast switching capabilities due to their superior material properties, and are considered potential candidates to replace Si devices for traction inverters in electrified vehicles in future. However, due to the comparatively low gate threshold voltage, SiC devices may encounter oscillatory false triggering especially during fast switching. This paper analyzed the causes of false triggering, and also studied the impact of a critical parasitic parameter - common source inductance. It is shown that crosstalk is the main cause for the false triggering in the case and some positive common source inductance help to mitigate the crosstalk issue. A packaging layout method is proposed to create the positive common source inductance through layout of control terminals / busbars, and/or the use of control terminal bonded wires at different height.

Thermal comfort in automotive seating has been studied and discussed for a long time. The available research, because it is focused on the components, has not produced a model that provides insight into the human-seat system interaction. This work, which represents the beginning of an extensive research program, aims to establish the foundation for such a model. This paper will discuss the key physiological, psychological, and biomechanical factors related to perceptions of thermal comfort in automotive seats. The methodology to establish perceived thermal comfort requirements will also be presented and discussed.

An experimental study of the acoustic characteristics of automotive catalytic converters is presented. The investigation addresses the effects and relative importance of the elements comprising a production catalytic converter assembly including the housing, substrate, mat and seals. Attenuation characteristics are measured for one circular and one oval catalytic converter geometry, each having 400 cell per square inch substrates. For each geometry, experimental results are presented to address the effect of individual components in isolation, and in combination with other assembly components. Additional experiments investigate the significance of acoustic paths around the substrate and through the peripheral wall of the substrate. The experimental results are compared to address the significance of each component on the overall attenuation.

High cycle fatigue material properties are not uniformly distributed on cylinder heads due to the casting process. Virtual Aluminum Casting (VAC) tools have been developed within Ford Motor Company to simulate the effects of the manufacturing process on the mechanical properties of cast components. One of VAC features is the ability to predict the high cycle fatigue strength distribution. Residual stresses also play an important role in cylinder head high cycle fatigue, therefore they are also simulated and used in the head high cycle fatigue analysis. Cylinder head assembly, thermal and operating stresses are simulated with ABAQUS™. The operating stresses are combined with the residual stresses for high cycle fatigue calculations. FEMFAT™ is used for the high cycle fatigue analysis. A user-defined Haigh diagram is built based on the local material properties obtained from the VAC simulation.

Assembly operators are rarely observed performing one-handed tasks where the unutilized hand is entirely inactive. Therefore, this study was designed to determine the forces applied to supporting hands, by automotive assembly operators, during common one-handed tasks such as hose installations or electrical connections. The data were computed as a percentage of body weight and a repeated measures analysis of variance (ANOVA) (p<0.05) was conducted. Supporting hand forces were observed to range from 5.5% to 12.1% of body mass across a variety of tasks. The results of this study can be used to account for these supporting hand forces when performing a biomechanical/ergonomic analysis.

To address the need of increasing fuel economy requirements, automotive Original Equipment Manufacturers (OEMs) are increasing the number of turbocharged engines in their powertrain line-ups. The turbine-driven technology uses a forced induction device, which increases engine performance by increasing the density of the air charge being drawn into the cylinder. Denser air allows more fuel to be introduced into the combustion chamber, thus increasing engine performance. During the inlet air compression process, the air is heated to temperatures that can result in pre-ignition resulting and reduced engine functionality. The introduction of the charge air cooler (CAC) is therefore, necessary to extract heat created during the compression process. The present research describes the physics and develops the optimized simulation method that defines the process and gives insight into the development of CACs.

Static seating bucks have long been used as the only means to subjectively appraise the vehicle interior packages in the vehicle development process. The appraisal results have traditionally been communicated back to the requesting engineers either orally or in a written format. Any design changes have to be made separately after the appraisal is completed. Further, static seating bucks lack the flexibility to accommodate design iterations during the evolution of a vehicle program. The challenge has always been on how to build a seating buck quickly enough to support the changing needs of vehicle programs, especially in the early vehicle development phases. There is always a disconnect between what the seating buck represents and what is in the latest design (CAD), since it takes weeks or months to build a seating buck and by the time it is built the design has already been evolved. There is also no direct feedback from seating buck appraisal to the design in CAD.

As part of determining the circumstances of a crash, sometimes components or component assemblies are evaluated to identify if they were damaged as a result of the crash or if they lost function prior to the crash. What role the loss of function may have contributed to the crash is useful in determining if they lost function prior to the crash. The causes and conditions for a brake rotor hub separation from the spindle of a vehicle with tapered roller bearing designs are analyzed through both component level testing and full vehicle testing. Laboratory tests were performed on component assemblies where loads were applied to the wheel assembly and the residual damage to the components was documented. In addition, full vehicle testing was conducted to evaluate the effects of a hub and rotor separation on vehicle control and to document evidence on the components. Real world case studies of hub and rotor separations are presented.

This paper presents the development and applications of engine friction algorithms to quickly estimate performance, optimum geometry of critical engine components, and packaging for rapid engine concept assessments. The development and implementation of some knowledge-based design rules will also be presented to quickly estimate the critical geometry of engine components and component weight such as valve sizing, piston weight, crankshaft geometry, etc. Some examples of powertrain concept design, such as the estimation of friction and packaging will be presented. The simulation results of the friction algorithms will be compared to some of available experimental data and also other friction estimation methods.

Build variation is an important aspect of vehicle assembly. However traditional variation analysis assumes parts are rigid, leading to overestimation of variations. A finite element analysis procedure to estimate the build variation due to variations of shape, size and mechanical properties of flexible parts is presented. In addition to the part deformation, assembly force and stress can also be calculated by this method. This procedure is illustrated with an example problem.

Today, the interior noise perceived by the occupants is becoming an important factor driving the design standards for the design of most of the interior assemblies in an automotive vehicle. Buzz, Squeak and Rattle (BSR) is a major contributor towards the perceived noise of annoyance to the vehicle occupants. An automotive vehicle consists of many assemblies such as instrumentation panel, doors, sun/moon-roof, deck lids, hood, etc. which are the potential sources of BSR noise. The potential locations of critical BSR noise could be contained within such assemblies as well as across their boundaries. An extensive study is made regarding the overall structural behavior as well as their interaction under typical road loads to come up with enhanced design for improved quality from the BSR noise perspective. The alternative designs were comparatively evaluated for their relative noise level from buzz, squeak and rattle perspective using an analytical tool - N-hance.BSR.

Automotive manufacturing presents unique challenges for ergonomic analysis. The variety of tasks and frequencies are typically not seen in other industries. Moving these challenges into the realm of digital human modeling poses new challenges and offers the opportunity to create and enhance tools brought over from the traditional reactive approach. Chiang et al. (2006) documented an enhancement to the Siemen's Jack Static Strength Prediction tool. This paper will document further enhancements to the ErgoSolver (formerly known as the Ford Static Strength Prediction Solver).

The automotive refrigerant systems can occasionally exhibit a transient hoot/whistle type noise under certain operating conditions. High pressure/velocity refrigerant flow through an evaporator core can readily excite the inherent acoustical and/or structural modes, resulting in audible transient tones. This condition if present can be experienced while driving away from a short stop and can last 2 to 10 seconds. The ambient conditions suitable for creating this noise are - moderate/high air-conditioning (A/C) load during days at 85-95° F temperatures with high humidity. Possible noise generating mechanisms have been discussed in earlier publications and our findings during this study indicate that they are excited by the high velocity superheated refrigerant vapor flow through the evaporator core plates. Examples of this transient noise and its spectral characteristics are presented to characterize this refrigerant system induced issue.

Sunroof is placed in certain high-end vehicles to give user a better driving experience. All automakers are searching alternatives to reduce weight and cost in the vehicle, in which sunroofs are also impacted. Some alternatives are already applied, as a honeycomb paper used in some sunshades that presents benefits, as less weight and with a good cost reduction. Although, due the reduced weight for this part produced in this material, it shows more susceptibility to reproduce the vibration that vehicle propagates in movement, especially in bad condition roads. The sunroof assembly is dependent of the roof reinforcement and roof skin, but in this special case, the validation could be done in the components itself because the interaction of the sunshades is directly dependent of the other sunroof parts, as rails and front frame.