Search Results

The 2005 Ford GT high performance sports car was designed and built in keeping with the heritage of the 1960's LeMans winning GT40 while maintaining the image of the 2002 GT40 concept vehicle. This paper reviews the technical challenges in designing and building a super car in 12 months while meeting customer expectations in performance, styling, quality and regulatory requirements. A team of dedicated and performance inspired engineers and technical specialists from Ford Motor Company Special Vehicle Teams, Research and Advanced Engineering, Mayflower Vehicle Systems, Roush Industries, Lear, and Saleen Special Vehicles was assembled and tasked with designing the production 2005 vehicle in record time.

The cyclic behavior of single overlap aluminum joints joined through a number of different methods has been investigated using Alcan 5754-O, an alloy that potentially could be used in structural applications. Overlap shear tests of spot welded, clinched and riveted joints are compared on the basis of their fatigue performance. The fatigue response of the spot welded joint was the baseline to which the other fasteners were compared. Test results showed an improvement of approximately 25% for both the mechanical clinch joints and aluminum rivets in fatigue strength at 106 cycles. The most significant improvement in fatigue strength of 100% was found for the self piercing rivets at 106 cycles. The failure behavior of the various joining methods is discussed as well as the surface appearance.

A cycle counting algorithm that will reduce a complex history into a series of discrete cycles is presented. The cycles determined by this technique are defined as closed stress-strain hysteresis loops of the type obtained from constant amplitude tests. Using the computer cycle counting algorithm, life predictions were made and compared with experimental results. These predictions were found to be typically within a ±3 factor of error. Also, the computer counting method was found to yield more accurate life predictions when compared to the histogram and range counting methods.

Due to magnesium alloy's poor weldability, other joining techniques such as laser assisted self-piercing rivet (LSPR) are used for joining magnesium alloys. This research investigates the fatigue performance of LSPR for magnesium alloys including AZ31 and AM60. Tensile-shear and coach peel specimens for AZ31 and AM60 were fabricated and tested for understanding joint fatigue performance. A structural stress - life (S-N) method was used to develop the fatigue parameters from load-life test results. In order to validate this approach, test results from multijoint specimens were compared with the predicted fatigue results of these specimens using the structural stress method. The fatigue results predicted using the structural stress method correlate well with the test results.

In this paper, a soft computing approach to a model-free vehicle stability control (VSC) algorithm is presented. The objective is to create a fuzzy inference system (FIS) that is robust enough to operate in a multitude of vehicle conditions (load, tire wear, alignment), and road conditions while at the same time providing optimal vehicle stability by detecting and minimizing loss of traction. In this approach, an adaptive neuro-fuzzy inference system (ANFIS) is generated using previously collected data to train and optimize the performance of the fuzzy logic VSC algorithm. This paper outlines the FIS detection algorithm and its benefits over a model-based approach. The performance of the FIS-based VSC is evaluated via a co-simulation of MATLAB/Simulink and CarSim model of the vehicle under various road and load conditions. The results showed that the proposed algorithm is capable of accurately indicating unstable vehicle behavior for two different types of vehicles (SUV and Sedan).

Automakers have the opportunity to utilize bio-based composite materials to lightweight cars while replacing conventional, nonrenewable resource materials. In this study, Life Cycle Assessment (LCA) is used to understand the potential benefits and tradeoffs associated with the implementation of bio-based composite materials in automotive component production. This cradle-to-grave approach quantifies the fiber and resin production as well as material processing, use, and end of life for both a conventional glass-reinforced polypropylene component as well as a cellulose-reinforced polypropylene component. The comparison is calculated for an exterior component on a high performance vehicle. The life cycle primary energy consumption and global warming potential (GWP) are evaluated. Reduced GWP associated with the alternative component are due to the use of biomass as process energy and carbon sequestration, in addition to the alternative material component's lightweighting effect.

This paper presents the application of a proposed fuzzy inference system as part of a stability control design scheme implemented with active steering actuator sets. The fuzzy inference system is used to detect the level of overseer/understeer at the high level and a speed-adaptive activation module determines whether an active front steering, active rear steering, or active 4 wheel steering is suited to improve vehicle handling stability. The resulting model-free system is capable of minimizing the amount of model calibration during the vehicle stability control development process as well as improving vehicle performance and stability over a wide range of vehicle and road conditions. A simulation study will be presented that evaluates the proposed scheme and compares the effectiveness of active front steer (AFS) and active rear steer (ARS) in enhancing the vehicle performance. Both time and frequency domain results are presented.

A new bumper system which provides 8 kph (5 mph) vehicle protection with superior quality, outstanding durability and high value is in production. The system includes five new technologies: Hot stamped, ultra high strength front beam, 970 N/mm2 (160 KSI) which also is the #1 body structure crossmember. Ultra high strength roll formed rear beam 1150 N/mm2 (190 KSI). polypropylene foam isolators designed for controlled energy management Thermoplastic olefin (TPO), injection molded fascias Two component urethane paint for long term color, gloss and scratch resistance. This bumper system, installed on over 100,000 vehicles so far, meets both MPV and passenger car 8 kph standards. Consumer and insurance industry trends indicate increasing demand for Multi Purpose Vehicle (MPV) bumper systems which meet 8 kph criteria. The major competitors in the MPV market (Aerostar, Grand Caravan, Toyota Previa, GM APV's, and Mazda MPV) have either 0 kph or at best 4 kph systems.

An estimate of the rate of attrition of passenger cars, needed to establish the service life expectancy of passenger cars, is of major interest whenever long range production plans are made, marketing strategies are developed, the total needs of vehicles on the roads are estimated, etc. Estimation of vehicle attrition is very complex, however, due to the lack of accurate data and the interaction of the parameters affecting attrition. In 1980 and 1985, similar studies of attrition [1,2] utilized vehicle registration data available as of July, 1979 and as of July, 1984. The object of this paper is to update the results of these papers, using the 1991 July registration data, available in May 1992. Within the scope of this paper the attrition rates of various passenger cars are compared and the effect of geographical location on the attrition rates and the change in attrition rates during the past twenty years are discussed.

The galvanostatic polarization method was used to determine the pitting potentials of candidate wrought aluminum alloys in inhibited ethylene glycol engine coolants. It was shown that the relative value of the pitting potential is an excellent measure of the long-term effectiveness of the coolants in preventing spontaneous pitting and crevice attack in the aluminum heat exchangers. The long-term effectiveness was determined by metallographic examination of aluminum heat exchangers subjected to a four-month, 50,000 mile simulated service circulation test.

It is frequently useful to calculate the theoretical composition of the major components of vehicle exhaust. A software program has been written in Basic (or Quick Basic) which allows the convenient calculation of volume percents of CO, CO2, O2, H2, and H2O from fuel composition (H/C and O/C ratios), the water content (dew point) of the combustion air, and a chosen stoichiometry (air/fuel ratio). The program considers the Water Gas Shift reaction and the production of hydrogen under fuel rich conditions. The program is valid for both standard gasolines and oxygenated blends. Vehicle emissions data, collected to compare values calculated by the program with actual experimentally determined values from vehicle exhaust, show good agreement for measurements made at a series of air/fuel ratios ranging from lambda of 0.85-1.2.

Manual Materials Handling has been historically recognized as one of the more prevalent causes for work related lost time injuries. Many manufacturing facilities use Material Handling Systems (lift/ tilt tables, hoists, articulated arms), often to alleviate ‘ergonomic’ stressors as well as to optimize production. If not used appropriately, Material Handling Systems can create new ergonomic concerns, or in some cases increase the physical demands of a job. A strategy designed to optimize the fit between the operator, the appropriate equipment and the operation is addressed in this paper.

Fatigue analysis using finite element models of a full vehicle body structure subjected to proving ground durability loads is a very complex task. The current paper presents an analytical procedure for fatigue life predictions of full body structures based on a time-domain approach. The paper addresses those situations where this kind of analysis is necessary. It also discusses the major factors (e.g., stress equivalencing procedure, cycle counting method, event lumping and load interactions) which affect fatigue life predictions in the procedure. A comparison study is conducted which explores the combination of these factors favorable for realistic fatigue life prediction. The concepts are demonstrated using a body system model of production size.

This paper presents the progress of an ongoing vehicle micro corrosion environment study. The goal of the study is to develop an improved method for estimating vehicle corrosion based on the Total Vehicle Accelerated Corrosion Test at the Arizona Proving Ground (APG). Although the APG test greatly accelerates vehicle corrosion compared to the field, the “acceleration factor” varies considerably from site-to-site around the vehicle. This method accounts for the difference in corrosivity of various local corrosion environments from site-to-site at APG and in the field. Correlations of vehicle microenvironments with the macroenvironment (weather) and the occurrence of various environmental conditions at microenvironments are essential to the study. A comparison of results from APG versus field measurements generated using a cold rolled steel based corrosion sensor is presented.

This paper discusses the testing for retentivity of non-volatile memories. The physics associated with the reliable production of various non-volatile data storage devices has long been a topic of debate. The ability to reliably produce devices which endure erase/write cycling and retain data for extended periods of time has been questionable. Recent improvements in IC processing has given rise to claims of enhancements in both of these areas. Non-volatile memories are attractive in many automotive electronic applications where battery backup is neither convenient or feasible, but because of reliability concerns they have not found their way into critical applications. In applications like odometer or emission control calibrations it is imperative that memory retention is assured. In order to verify the reliability of the various available non-volatile memory devices, an accelerated test program was instituted.

This paper proposes a novel algorithm. This algorithm is called Self-Organizing Fuzzy Neural Network (SOFNN). SOFNN revolutionizes how researchers apply control theories, image/signal processing on control systems and other applications. In general, SOFNN is an identification technique that automatically initiates, builds and fine-tunes the required network parameters. SOFNN evaluates required structures without predefined parameters or expressions regarding systems. SOFNN sets out to learn and configure a system's characteristics. Self-constructing and self-tuning features enable SOFNN to handle complex, non-linear, and time-varying systems with higher accuracy, making systems identification easier. SOFNN constructs and fine-tunes the system parameter through two phases. The two phases are the construction and the parameter-tuning phase. The two phases run concurrently allowing SOFNN to identify systems on-line.

A highly adaptable fatigue testing computer system is presented for controlling single or multichannel test machines. The system imposes most common varieties of waveforms and also provides time synchronization between channels, such as in the case of variable amplitude biaxial load histories, and monitors various feedback signals for both data acquisition and alarm purposes. The program operates in a real-time Unix system as a separate stand-alone process. Communication with other users or the operator is done only through a reserved common block of shared memory. This feature allows control and monitoring of all tests over the computer network. A user can simply login remotely and check the test or start a data acquisition task from any workstation in the company, and then take the data files and analyze them on other computers. This paper describes the operation of the software, the methodology behind the hardware selection and the software structure.

A number of advancements have been made in the coulometric sulfur trace instrumental technique for the real-time measurement of engine oil economy. These advancements include modification of the coulometric cell to improve reliability and reproducibility. The instrument has been interfaced with a microcomputer for instrument control as well as data acquisition, storage, and analysis. Studies were undertaken which demonstrate sufficient sensitivity and linearity for determination of engine oil economy at levels better than 10,000 miles/quart. Applications to steady-state engine oil consumption mapping and to instantaneous oil consumption during transient engine cycling are described. These instruments are being produced by an outside supplier for use in various company locations in both the engine production and engine research environments.

Magnesium die-cast alloys are known to have a layered microstructure composed of: (1) An outer skin layer characterized by a refined microstructure that is relatively defect-free; and (2) A “core” (interior) layer with a coarser microstructure having a higher concentration of features such as porosity and externally solidified grains (ESGs). Because of the difference in microstructural features, it has been long suggested that removal of the surface layer by machining could result in reduced mechanical properties in tested tensile samples. To examine the influence of the skin layer on the mechanical properties, a series of round tensile bars of varying diameters were die-cast in a specially-designed mold using the AM60 Mg alloy. A select number of the samples were machined to different final diameters. Subsequently, all of the samples (as-cast as well as machined) were tested in tension.

The fatigue strength and failure behavior of A5754-O adhesively bonded single lap joints by a hot-curing epoxy adhesive were investigated in this paper. The single lap joints tested include balanced substrate joints (meaning same thickness) and unbalanced substrate joints, involving combinations of different substrate thicknesses. Cyclic fatigue test results show that the fatigue strength of bonded joints increase with the increasing substrate thickness. SEM and Energy Dispersive X-ray (EDX) were employed to investigate the failure mode of the joints. Two fatigue failure modes, substrate failure and failure within the adhesive were found in the testing. The failure mode of the joint changes from cohesive failure to substrate failure as the axial load is decreased, which reveals a fatigue resistance competition between the adhesive layer and the aluminum substrate.