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This paper introduces for the first time a fully connectorized passive optical star for use with plastic optical fiber that addresses all automotive application requirements. A unique mixing element is presented that offers linear expandability, uniformity of insertion loss, and packaging flexibility. The star is constructed of all plastic molded components to make it low cost and produceable in high volume and is single-ended to facilitate vehicle integration. The star is connectorized to facilitate assembly into the vehicle power and signal distribution system.

This paper discusses an analytical technique for computing the failure rate of steel springs used in automotive part applications. Preliminary computations may be performed and used to predict spring failure rates quickly at a very early stage of a product development cycle and to establish program reliability impact before commitment. The analytical method is essentially a combination of various existing procedures that are logically sequenced to compute a spring probability of failure under various operational conditions. Fatigue life of a mechanical component can be computed from its S-N curve. For steels, the S-N curve can be approximated by formulae which describe the fatigue life as a function of its endurance limit and its alternating stress. Most springs in service are preloaded and the actual stress fluctuates about a mean level. In order to compute an equivalent alternating stress with zero mean, an analytical method based on the Goodman Diagram is used.

The Cadillac Electronic Climate Control heating and air conditioning system provides automatic control of the passenger compartment temperature. It utilizes a microcomputer to control the operation of electrical, mechanical and vacuum components that regulate the amount and temperature of air delivered into the car to maintain the “customer set” comfort level. The first step in the evolution of this new system was to define the performance requirements. With this established, the system was then designed, tested and developed in the laboratory and on the road until this desired performance was achieved.

Build variation has long been recognized as one of the most important factors in vehicle performance. In this study an elastic assembly simulation program is used to guide a wheelhouse assembly process design to reduce build variation. Five (5) different clamping schemes are evaluated through the simulation program. From the five proposed process design choices, the best assembly process was identified, which results in reduced assembly variation and less tooling and manufacturing costs. Two different variation simulation approaches, one based on perturbation and the other based on Design of Experiments, were used to predict the assembly variation. Good agreement between the two approaches provided a validity check for the simulation tool.

Constrained Layer Damping (CLD) treatments have long provided a means to effectively impart damping to a structure [1, 2 and 3]. Traditionally, CLD treatments are constructed of a very thin polymer layer constrained by a thicker metal layer. Because the adhesion of a thin polymer layer is very sensitive to surface finish, surfaces that a CLD treatment can be effectively applied to have historically been limited to those that are very flat and smooth. New developments in material technology have provided thicker materials that are very effective and less expensive to apply when used as the damping layer in a CLD treatment. This paper documents the effectiveness of such a treatment on a cast aluminum front cover for a V6 engine. Physical construction of the treatment, material properties and design criteria will be discussed. Candidate applications, the assembly process, methods for secondary mechanical fastening will be presented.

As component and systems sophistication in both cars and trucks increase, improved diagnostic capabilities are required to assure proper and expedient serviceability. Replacement of electrical modules, starter motors, carburetors, fuel injectors and even whole engines or transmissions is encouraged by high labor costs and continued vehicle mobility mandates. The remanufacturing business has grown and components previously discarded now provide valuable core elements to feed the industry. To achieve efficient utilization of capital, equipment and labor, remanufacturers must estimate when this supply of core elements will be available and plan their production schedules accordingly. In order to properly service private individuals and commercial fleets, minimize vehicle downtime and reduce life cycle costs, adaptation of available analytical tools must be made.

Casting, machining and structural simulations were completed on a V8 engine block made in Compacted Graphite Iron (CGI) for use in a racing application. The casting and machining simulations generated maps of predicted tensile strength and residual stress in the block. These strength and stress maps were exported to a finite element structural model of the machined part. Assembly and operating loads were applied, and stresses due to these loads were determined. High cycle fatigue analysis was completed, and three sets of safety factors were calculated using the following conditions: uniform properties and no residual stress, predicted properties and no residual stress, and predicted properties plus residual stress.

Free form fabrication, or rapid prototyping as it is commonly known, is the creation of a physical entity, directly from numerical description, using an additive process. The mathematical data used is typically in the form of a 3D CAD file, but it may also be obtained from a reverse engineering process. This paper presents a review of three of the leading FFF (free form fabrication) systems which are commercially available. Time constraints will allow us to describe only three of these products. Although this does not do justice to a technology where there are more than 30 different systems in various stages of development, these examples represent the vast majority of machines which are in the marketplace today.

The purpose of this paper is to provide an overview of the process of selection, development and approval of General Motors original equipment TPC passenger car tires. We have attempted to minimize detail in each specific area, but intend to provide a general comprehension of the thought processes involved and the procedures used to select the proper tire size and type for a vehicle. We will then describe the tire performance criteria involved in the overall development and approval process and will subsequently consider tire noise requirements in somewhat greater detail. The paper will conclude by describing the General Motors Tire Performance Criteria (TPC) System, which is a documentation of the General Motors Tire Performance requirements and test procedures.

This paper presents a new computerized approach for designing the automobile window glass contour, the glass drop motion, and the regulator systems. The three-dimensional geometrical relationship of the glass contour, the drop path, and its guidance system have been studied. Methods for barrel and helical drops are presented for optimizing the glass profile and drop path trajectories. Criteria for perfecting the glass contour are developed for shaping the profile of the vehicle clay model. Methods for correcting the glass contour and shape are presented. Examples are provided to illustrate how to improve the design. This approach integrates the development works of glass contour, drop motion and regulator systems. Through this design approach the window glass can fit and move perfectly in the door assembly.

A search for methods of switching a proposed three beam headlight system led to the evaluation of 41 possible schemes. Human factors criteria reduced the original 41 to three systems which were tested in a laboratory with a broad range of subjects. Recordings of practice trials, learning trials, and the responses to visual cues projected on a screen were analyzed. The same test procedure was also used to compare three alternative ways of switching conventional two beam headlight systems. Summary data is presented for the six systems tested grouped by test subject age, sex, and driving experience. The most pronounced difference observed was in the subjective preference rating among two beam switching systems. All systems tested resulted in remarkably few learning and practice trials. Small differences were recorded among systems in operational response time.

From November 1970 through August 1971 an extensive program of static and dynamic air cushion inflation tests utilizing human volunteers was conducted at Holloman Air Force Base, New Mexico, sponsored by the Department of Transportation. Forty-one full cushion deployment static firings were made, with air cushion hardware and seating buck environment designed by General Motors. The static series was followed by 35 dynamic sled firings of human volunteers, beginning at 8.6 g (15.1 mph) and culminating at 21.7 g (31.5 mph). A major objective of both the static and dynamic test series was to identify changes in air-cushion design found necessary to improve its protective capability for human beings. Because of the severity of cushion deployment, one modification was made following the initial static tests: The orifice diameter size of the bag inlet was reduced from 1.0 to 0.6 in to diminish the rapidity of bag inflation. This modification proved effective in the dynamic series.

By using descriptive charts and graphs, this report provides an analysis of the IDB-C network at the Subsystem level and at the vehicle level, using data comparison between modeling and simulation of the network and measurement and analysis on physical systems.

Since 1997, General Motors Body Manufacturing Engineering - Die Engineering Services (BME-DES) has been working jointly with our software vendor to develop and implement a parallel version of stamping simulation software for mass production analysis applications. The evolution of this technology and the insight gained through the implementation of DMP/MPP technology as well as performance benchmarks are discussed in this publication.

This report summarizes the methodology used in automotive industry for virtual evaluation of vehicle structural integrity under abusive load cases. In particular, the development of a nonlinear finite element (FE) centric approach is covered that is based on the functions implemented in ABAQUS (by ABAQUS Inc.). An overview is also given for comparative study of the ABAQUS capability with the existing ADAMS (MSC Software) based methods.

This paper describes a numerical simulation technique applicable to the FMVSS 214 side impact test through the use of the finite element method (FEM) technology. The paper outlines the development of the side impact dummy (SID), moving deformable barrier (MDB) and the test vehicle FEM models, as well as the development of new advanced constitutive models of materials and algorithms in LS-DYNA3D which are related to the topic. Presented in the paper are some initial simulation problems which were encountered and solved, as well as the correlation of the simulation data to the physical test.

The performance and production requirements for future passenger vehicles has increased the efforts to replace metal body panels with plastic materials. This has been accomplished, to a large extent on some production vehicles that have been introduced recently. Unfortunately, these plastic body applications have necessitated special off-line handling or low temperature paint processing. However, the advantages of RIM nylon, offer the potential for uniquely new plastic body designs, that can be processed through existing assembly plants, much like the steel panels they are intended to replace. The intent of this paper is to discuss the rationale for future plastic body panel material selection and related nylon RIM development efforts.

The work presented here builds on the practical and effective spot weld fatigue life prediction method, the structural stress method (SSM), that was developed at Stanford University. Constant amplitude loading tests for various spot weld joint configurations have been conducted and the SSM has been shown to accurately predict fatigue life. In this paper refinements to the structural stress approach are first presented, including a variable amplitude fatigue life prediction method based on the SSM and Palmgren-Miner's rule. A test matrix was designed to study the fatigue behavior of spot welds under tensile shear loading conditions. Constant amplitude tests under different R-ratios were performed first to obtain the necessary material properties. Variable amplitude tests were then performed for specimens containing single and multiple welds.

Typically, “Reliability and Maintainability (R&M)” is perceived as a tool for products alone. Putting emphasis on reliability only at the cost of maintainability is another archetype. Inclusion of both reliability and maintainability (R&M) in all the phases of the machinery and equipment (M&E) life cycle is required in order to be world competitive in manufacturing. R&M is mainly a design function and it should be a part of any design review. Inclusion of the R&M concept early in the life cycle of M&E is key to cost effective and competitive manufacturing. Neither responsive manufacturing nor preventive maintenance can raise it above the level of inherent R&M.