Mold designers and foundrymen spend a lot of time in developing molds without knowing exactly the phenomena which take place inside. Simulor, which has been used in an industrial environment for two years, offers the solution to make foundrymen understand what happens during the filling of the mold and the solidification of the part. Based on navier-stokes and heat transfer equations, simulor provides speed distribution and metal front evolution in the cavity and thermal map in the mold and the part. Some examples with different metals (cast iron, aluminum alloy) cast with various processes (sand or die casting, low pressure or gravity casting) will be given. This new tool will given foundrymen the opportunity to test the mold before having it machined and will also allow reduction in development delays.
In order to improve the design of drawn parts and to reduce the number of trial and error tests, Renault has undertaken the development and the validation of various finite element procedures and codes. This paper describes the function of each software and its level of integration into the design process. One of them is already an operational tool used be planners whilst the others are still in the validation phase. Selected examples show typical applications of the computer programs on automotive parts.
The pending changes in European law enabling the use of plastic lenses on vehicle headlamps provide an opportunity for further advancement of vehicle styling, lighting performance and aerodynamic efficiency. Plastic lenses can also provide a useful weight saving and contribute to energy savings during the lifetime of the vehicle. This paper discusses the current requirements, technologies and solutions for plastic lenses, and indicates the way this advance can impact on the evolution of lighting products.
The paper review some recent efforts, made by the aluminum industry, towards the development of new advanced alloys for aerospace applications; unconventional production technologies and MMC occupy an outstanding position in this context. Raid solidification processes are currently used for obtaining advanced alloys and, among them, the powder metallurgy route is one of the most commonly applied, since it has reached a considerable level of maturity. Experimental results of PM materials are shown and discussed in order to appreciate the potentialities of this class of materials and some recent further progress is shown: the spray deposition approach (osprey process). After having described the main features of the osprey process, some results obtained at the Department of Aerospace Engineering of Pisa about the development of high strength Al-alloy and MMC obtained by means of the osprey process are shown.
An overview of high strength thermoset and thermoplastic composites will provide a basis of comparison with exotic hybrid composites. A specific theoretical application for a very high strength unibody application will be presented and test results evaluated. A critical overview of immediate applications will be presented and evaluated. In conclusion, it will be suggested that a uniform standard of performance be established for the practical application's requirements for these materials
The article emphasizes the effect of flow on dimensional stability, mechanical properties and surface finish, and the close coupling of dimensional stability and mechanical properties. Warpage is the result of the balance between the structural stiffness of the part and the stress pattern resulting in variation in shrinkage due to area shrinkage, orientation, and thermal effects. The practical solution to warpage depends on the use of software to isolate the basic causes of warping which then leads to a logical solution procedure.
An inexpensive driving simulation system with sufficient fidelity has been developed. The system produces motion cues of four degrees of freedom, visual and auditory cues, and control feel on the steering wheel. This paper describes the features of this newly developed system and gives examples that demonstrate its effectiveness. The motion cues provided in this system are yaw, heave, and lateral and fore/aft accelerations. The lateral and fore/aft accelerations are simulated by tilting the simulator compartment. A computer-processed road image is given through a CRT monitor. The restoring torque of the steering wheel is produced by an electrical servosystem via a coil spring. Cruising sound is given in order to improve speed perception. Since the system uses digital computers, the vehicle characteristics are altered easily by merely rewriting the software. This enables us to simulate special vehicle dynamics such as front & rear wheel steering.
Many areas of the world are in various stages of development which frequently includes a rapid increase in the motor vehicle population. As a result, some areas are beginning to show the effect of increased motor vehicle use on air pollution. The vehicle's contribution to California's air pollution has long been recognized and studied, and measures have been implemented to reduce emissions from motor vehicles. The history of light duty vehicle emission control in the South Coast Air Basin of California is reviewed. Emission reductions achieved, current levels, projected future emissions and the need for further emissions reductions from light duty vehicles are discussed. For other areas of the world where motor vehicles contribute to air pollution, suggestions are made which can improve the effectiveness of emission control efforts; which should be consistent with political and economic realities, and efforts to achieve international harmonization of standards.
Statistical Energy Analysis (SEA) method is used to predict Sound Transmission Loss (STL) of sound barrier assemblies (SBA) commonly used in automotive dashmat design. Tests are performed for dashmat plaques with and without design features, and SEA equations have been used for predicting transmission loss with acceptable accuracy below the interception (cavity resonance) frequency. For frequency range higher than interception point, the SEA software used overestimates STL. For dashmat tests with design features, test results and SEA predictions are generally agreeable.
An overview of model development for seated occupants is presented. Two approaches have been investigated for modeling the vertical response of a seated dummy: finite element and simplified mass-spring-damper methods. The construction and implementation of these models are described, and the various successes and drawbacks of each modeling approach are discussed. To evaluate the performance of the models, emphasis was also placed on producing accurate, repeatable measurements of the static and dynamic characteristics of a seated dummy.
A hardware / software package is presented that is used to determine the dynamic mechanical properties of viscoelastic materials as a function of temperature and frequency. The material properties can then be used to aid in the design of surface damping treatments for various engineering structures.
This paper describes the procedures used to reduce the tonal noise of a class eight truck engine timing gear train that was initially found to be objectionable under idle operating conditions. Initial measurements showed that the objectionable sounds were related to the fundamental gear mesh frequency, and its second and third harmonics. Experimental and computational procedures used to study and trouble-shoot the problem include vibration and sound measurements, transmission error analysis of the gears under light load condition, and a dynamic analysis of the drive system. Detail applications of these techniques are described in this paper.
This paper argues in favor of a human-centered (anthropocentric) approach to modern manufacturing. The bases for these arguments are: (a) worker deskilling and creativity issues, (b) economics, and (c) unresolved problems in automation, such as software reliance and costs. Detailed arguments are avoided owing to space limitations. Finally, some issues confronting human-centered manufacturing are raised.
A design framework based on the principles of lean manufacturing and axiomatic design was used as a guideline for designing an automotive component manufacturing system. A brief overview of this design decomposition is given to review its structure and usefulness. Examples are examined to demonstrate how this design framework was applied to the design of a gear manufacturing system. These examples demonstrate the impact that low-level design decisions can have on high-level system objectives and the need for a systems-thinking approach in manufacturing system design. Results are presented to show the estimated performance improvements resulting from the new system design.
This paper explores the current status of error management strategies and human factors efforts within regional airlines. It briefly addresses the potential needs of the environment from a perspective of the market’s accident and incident history as well as anecdotal reports received from members of the regional airline community. It also raises questions concerning the applicability of human factors and error management strategies developed in other segments of aviation to the problems faced within regional airline environments.
Silencers are very often filled with absorbent fibers to optimize the acoustic performance, particularly when the volume is limited. The fibers have to meet several specifications concerning (1) acoustic damping as a function of frequency, (2) temperature stability, (3) processing, and (4) blow-out resistance. This paper will review the characteristic properties for continuous fibers including Advantex™ versus standard E Glass as well as discontinuous fibers such as basalt wool. The failure mechanism of the various fibers will be explored in detail. Thermal shock testing, single filament tensile strengths, and weight loss measurements will be used to contrast the failure mechanism of these fibers. Additionally, the acoustic performance of silencers filled with different fibers will be analyzed and compared. The selection of different filling materials is closely linked to the production process utilized.
This paper discusses the evolution of graduate education in manufacturing engineering and the curriculum needed to educate manufacturing engineers in the automotive industry. This paper examines the master's and doctoral curriculum in manufacturing engineering at the University of Michigan-Dearborn. Finally, it proposes future direction for graduate education in manufacturing that will be needed for the automotive industry of the future.