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This paper is intended to give a general overview of the key aerodynamic developments for the 2006 Chevrolet Corvette C6 Z06. Significant computational and wind tunnel time were used to develop the 2006 Z06 to provide it with improved high speed stability, increased cooling capability and equivalent drag compared to the 2004 Chevrolet Corvette C5 Z06.

Over the past 20 years, polyvinyl chloride (PVC) has almost replaced metal in stationary glass reveal moldings with dramatic part cost savings on cars and trucks world-wide. The process of assembly is generally simple and convenient but to replace a reveal molding can be difficult. Many times, in order to replace the molding, it may also be necessary to replace or reseal the glass. In short, PVC reveal moldings, relatively inexpensive parts, are very expensive to service. Outside of general assembly and processing issues, there are 5 variables that may cause a failure in the performance of a stationary glass reveal molding. They are as follows: material degradation, crystallization, plasticizer loss, material properties, and molded-in stress. Because of modern standard PVC formulations and the material requirements of most automotive companies, material degradation, crystallization and plasticizer loss do not commonly cause failure. Material properties and molded-in stress do.

For higher mileage vehicles, noise from contaminant ingress is one of the largest durability issues for wheel bearings. The mileage that wheel bearing sealing issues increase can vary due to multiple factors, such as the level of corrosion for the vehicle and the mating components around the wheel bearing. In general, sealing issues increase after 20,000 to 30,000 km. Protecting the seals from splash is a key step in extending bearing life. Benchmarking has shown a variety of different brake corner designs to protect the bearing from splash. This report examines the effect of factors from different designs, such as the radial gap between constant velocity joint (CVJ) slinger and the knuckle, knuckle labyrinth height and varying slinger designs to minimize the amount of splash to the bearing inboard seal. This report reviews some of the bearing seal failure modes caused by splash.

The complexity of vehicle-pedestrian collisions necessitates extensive validation of pedestrian computational models. While body components can be individually simulated, overall validation of human pedestrian models requires full-scale testing with post mortem human surrogates (PMHS). This paper presents the development of a full-scale pedestrian impact test plan and experimental design that will be used to perform PMHS tests to validate human pedestrian models. The test plan and experimental design is developed based on the analysis of a combination of literature review, multi-body modeling, and epidemiologic studies. The proposed system has proven effective in testing an anthropometrically correct rescue dummy in multiple instances. The success of these tests suggests the potential for success in a full-scale pedestrian impact test using a PMHS.

Since its very beginning in 1953, Corvette has been a pioneer in light weight material applications. The new 6th generation corvette high performance Z06 model required aggressive weight savings to achieve its performance and fuel economy targets. In addition to aluminum body structure and some carbon fiber components, the decision to use a magnesium front crossmember was identified to help achieve the targets. An overview of the Structural Cast Magnesium Development (SCMD) project will be presented which will provide information on key project tasks. Project focus was to develop the science and technical expertise to manufacture and validate large structural magnesium castings, which provide a weight reduction potential of 35 percent with respect to aluminum. The die cast magnesium cradle is being produced from a Mg-Al-RE alloy, designated AE44, for high temperature creep and strength performance as well as casting ductility requirements.

Free expansion of straight tubes is the simplest test to evaluate tube properties for hydroforming applications and to provide basic understanding of the mechanics of tube hydroforming. A circular cylindrical tube is sealed at both ends and fluid, usually water, is pumped into the tube to increase its internal pressure to bulge and burst the tube. Previous numerical simulations of the free expansion tube test were limited to modeling the midsection of the tube under various assumptions of deformation path. The simulation results obtained deviated from the experimental results under all simulation conditions considered. A new model is developed in this paper in which the whole tube is simulated instead of considering only its mid-section. Judged by the pressure-expansion relations, the model accurately predicted free expansion hydroforming tests results.

The following document is a set of guidelines intended to be used as a reference for the practicing automotive sound quality (SQ) engineer with the potential for application to the field of general consumer product sound quality. Practicing automotive sound quality engineers are those individuals responsible for understanding and/or conducting the physical and perceptual measurement of automotive sound. This document draws upon the experience of the four authors and thus contains many “rules-of-thumb” which the authors have found to work well in their many automotive related sound quality projects over the past years. When necessary, more detailed publications are referenced. The intent of publication of this document is to provide a reference to assist in automotive sound quality work efforts and to solicit feedback from the general sound quality community as to the completeness of the material presented.

Several methods are currently used to enforce motion in different types of noise and vibration models. Experimentally based FRF models often use a matrix inversion technique to enforce motion. In finite element models, the large mass method is one that is very commonly used. A literature review has shown few guidelines for determining the size of these large masses. In this paper, the relationship between the matrix inversion technique and the large mass method is derived. From this relationship, conditions necessary for these large mass FEM models to converge to the same answers as the matrix inversion technique are derived. These conditions are then used to develop a criterion for determining a smallest possible large mass. Results from a simple model are presented to demonstrate the criterion.

This paper is mainly focused on development of the methodology to predict the over-slam travel of the decklid using the LS DYNA model and the sensitivity of the parameters that affect the overslam travel such as weatherstrip, overslam bumper CLD and the location. The full factorial experiments approach is used for maximizing the possibility of finding a favorable result.

Over the past decade, the automotive industry has seen a rapid decrease in product development cycle time and an ever increasing need by original equipment manufacturers and their suppliers to differentiate themselves in the marketplace. This differentiation is increasingly accomplished by introducing new technology while continually improving the performance of existing automotive systems. In the area of automotive brake system design, and, in particular, the brake apply subsystem, an increased focus has been placed on the development of electrohydraulic apply systems and brake-by-wire systems to replace traditional pneumatic and hydraulic systems. Nevertheless, the traditional brake apply systems, especially vacuum-based or pneumatic systems, will continue to represent the majority of brake apply system production volume into the foreseeable future, which underscores the need to improve the performance and application of these traditional systems in passenger cars and light-trucks.

Glass run-channel seals are located between DIW (Door in White) and window glass. They are designed to allow window glass to move smoothly while other two major requirements are met; (1) Provide insulation to water leakage and noise, and (2) Stabilize the window glass during glass movement, door slamming and vehicle operation. For a robust glass guidance system, it is critical to minimize the variation of seal compression force. In addition, it is desired to maintain a low seal compression force, which meets the minimum requirement for insulating water leakage/noise and stabilizing the window glass, for enhancing the durability of glass guidance system. In this paper, a robust synthesis and design concepts on the glass run-channel seal is presented. The developed concept is demonstrated with test data.

Managing (minimizing and optimizing) the total mass of a vehicle is recognized as a critical task during the development of a new vehicle, as well as throughout its production lifecycle. This paper summarizes a literature review of, and investigation into, the strategies, methods and best practices for achieving low total mass in new vehicle programs, and/or mass reductions in existing production vehicle programs. Empirical and quantitative data and examples from the automotive manufacturers and suppliers are also provided in support of the material presented.

A review of available information on the effect that brake rotor crossdrilling has on brake performance reveals a wide range of claims on the subject, ranging from ‘minimal effect, cosmetic only’ to substantially improving brake cooling and fade resistance. There are also several theories on why brake rotor crossdrilling could improve fade performance, including crossdrill holes providing a path for ‘de-gassing’ of the brake lining material and increasing the mechanical interaction, or ‘grip’ of the lining material on the rotor. This paper reviews three case studies in which the opportunity arose to compare the performance of brake systems with crossdrilled versus non crossdrilled brake rotors in otherwise identical brake corner designs. The effect of brake rotor crossdrilling on brake cooling, brake output, brake fade, wet brake output, and brake wear rates were studied using both on-vehicle and dynamometer data.

An improvement in a vehicle's front of dash barrier assembly's acoustical performance has in the past been addressed by both adding individual absorbers and increasing the overall weight of the dash sound barrier assembly. Depending upon the target market of the vehicle, adding mass may not be an option for improved acoustical performance. Understanding the value of an increase in vehicle mass and / or cost for a specific level of improved acoustical performance continues to plague both Original Equipment Manufacturer (OEM) Engineers and Purchasing representatives. This paper examines the importance of properly sealing the front of dash pass-through areas and offers recommendations which can improve the overall vehicle acoustical performance without the addition of cost and mass to the vehicle.

Over the past five years, the US Automotive Materials Partnership (USAMP) has brought together representatives from DaimlerChrysler, General Motors, Ford Motor Company and over 40 other participant companies from the Mg casting industry to create and test a low-cost, Mg-alloy engine that would achieve a 15 - 20 % Mg component weight savings with no compromise in performance or durability. The block, oil pan, and front cover were redesigned to take advantage of the properties of both high-pressure die cast (HPDC) and sand cast Mg creep- resistant alloys. This paper describes the alloy selection process and the casting and testing of these new Mg-variant components. This paper will also examine the lessons learned and implications of this pre-competitive technology for future applications.

In recent years, the automotive industry has seen a rapid decrease in product development cycle time and a simultaneous increase in the variety of vehicles offered in the marketplace. These trends require a rigorous yet efficient systems engineering approach to the development of automotive braking systems. This paper provides an overview of an objective process for developing and predicting vehicle-level brake performance through an approach using both laboratory subsystem testing and math modeling.

The wear test introduced in this paper can be used to determine and rank PV (pressure time velocity) capability of plastic materials for applications where a plastic part is rotating or reciprocating against a metal surface. It provides an accelerated test method to evaluate the wear performance of plastic materials. A single test can provide tribological information at multiple PV conditions. The tribological information obtained from this method includes coefficient of friction, PV (pressure times velocity) limits, and interface temperature profile. This test is currently used by General Motors Corporation to develop plastic materials for transmission thrust washer and dynamic seal applications. The test is running in two sequences (A & B), capable of a PV range from 50,000 psi-ft/min 500,000 psi-ft/min, under dry conditions. The PV steps in sequence A are combinations of high pressure and low velocity - for applications where high loads are expected, such as thrust washers.