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During frontal and rear end type collisions, very large forces will be imparted to the passenger compartment by the collapse of either front or rear structures. NCAP tests conducted by NHTSA involve, among other things, a door openability test after barrier impact. This means that the plastic/irreversible deformations of door openings should be kept to a minimum. Thus, the structural members constituting the door opening must operate during frontal and rear impact near the elastic limit of the material. Increasing the size of a structural member, provided the packaging considerations permit it, may prove to be counter productive, since it may lead to premature local buckling and possible collapse of the member. With the current trend towards lighter vehicles, recourse to heavier gages is also counterproductive and therefore a determination of an optimum compartment structure may require a number of design iterations. In this article, FEA is used to simulate front side door behavior.

Focal Project I (FP-I) of the Automotive Composites Consortium (ACC) was initiated in early 1990 to focus on the use of composites in a vehicle's front end structure to perform crash energy management. The project is a continuation of a proprietary Ford project to replace the entire front structure of a production 1984 Escort with a molded composite front structure. Although FP-I uses existing RTM molding tools, the project focuses on the development of a completely new reinforcement architecture which emphasizes production feasible preforming methods: triaxially braided glass fibers over foam cores make up the upper and lower rails and the connecting panel can be formed from either thermoformed continuous strand mat or directed fiber. The process uses a vinyl ester resin. The front structure of the Escort has been redesigned and replaced with production-feasible composite components designed for crash energy management requirements as well as other overall structural considerations.

A finite element model for hybrid III dummy's lower torso is presented. All details of the dummy's knee structure are carefully considered. In order to justify the finite element model, numerical results are made to compare with the experimental results from both knee impact test and knee slider impact test. It is found that the finite element results agree very well with their experimental counterparts.

A scheme which addresses the determination of the time step for time integration of non-linear explicit structural dynamic equations is described. Explicit time integration algorithms based on nodal partitions and mass scaling for crash applications are presented. This allows for greater advantage to be taken of local stability criteria, and thus improves the efficiency of the explicit time integrator. Consistency, convergence and stability analyses of this algorithm for first order systems are given. Issues relating to the effect of user selection of the proper technique on the outcome of the analysis, are discussed. The adequacy of the technique is evaluated by measuring its performance in various benchmark model problems. Example problems are included to demonstrate the accuracy and stability of the method. The stability conditions for general integration parameters in an element partition are also discussed.

The dynamic behavior of the fuel inside a fuel tank and the fuel pressure caused by the acceleration of the vehicle during a rear crash will determine whether a damage of vehicle fuel system resulting in fuel leakage will occur. The dynamic behavior of the liquid and the gas in the fuel tank depends on the fuel tank capacity, shape, and the level which the fuel tank is filled. The mode and severity of the crash will also affect the pressure distribution inside the tank. In order to predict fuel system leakage in early stage of vehicle design before any test vehicles are made, it is necessary for the crash analyst to have a tool that can predict this phenomena. The analyst should have the capabilities to compute not only the fuel tank pressure, but also possible fuel system pipe cut during the crash.

The extensions to a basic explicit finite element code for execution in a parallel-distributed environment are described. A parallel-distributed implementation of the pinball algorithm for contact-impact is presented. The parallel algorithm employs message-passing for interprocessor communication. Nonlinear benchmark calculations for network-connected Hewlett Packard workstations and the IBM SP-1 are also presented.

Statistic shows the majority of real world frontal collisions involve only partial overlap of the vehicle front end. Thus the European Experimental Vehicle Committee (EEVC) has established a safety standard and test procedure utilizing a deformable barrier for offset impacts. The offset deformable barrier (ODB) is designed to represent the characteristics of a vehicle front end. Therefore, it can replace a target vehicle and the offset test can be conducted economically. Many component, sub-assembly and full vehicle system tests have been conducted in Ford using the EEVC ODB. Based on the various tests, the barrier responds differently depending on the front end design and the size of an impacting vehicle. Sometimes the front end of a test vehicle punches through the barrier. Also rupture of aluminum sheets and tearing of honeycomb materials are often observed in post-test barriers.

There is a trend in the automotive industry to reduce the number of physical prototypes and to rely more on Computer Aided Engineering (CAE) for sizing and final design of vehicle structures. The traditional deterministic approach does not necessarily clarify the degree of variability and conservatism. With small variability in influence parameters and a design factor for final design, the approach may be over conservative resulting in weight and cost penalty. On the other hand, with large variability and the same design factor, the deterministic approach may not satisfy durability requirements. It is important to identify the variability of all factors including road loads and sensitivities of the control parameters, and to minimize their effects on durability so that fatigue life distribution meets the durability requirements.

In order to accurately predict fatigue life of vehicle structures or components, it is necessary to predict dynamic stresses efficiently as well as accurately. This paper demonstrates how to improve the accuracy of dynamic stresses that are computed from the conventional flexible multibody dynamic system simulation where modal stress superposition method is used. In the proposed method, the mode-acceleration concept is utilized in each flexible component in the postprocessing stage of dynamic simulation. Numerical examples of a vehicle chassis structure show the effectiveness of the proposed method.

Service loading histories have the same general character for an individual route and the magnitudes vary from driver to driver. Both the magnitude and character of the loading history change from route to route and a linear scaling of one loading history does not characterize the variability of usage over a wide range of operating conditions. In this paper a technique for measuring and extrapolating cumulative exceedance diagrams to quantify the distribution of service loading in a vehicle is described. Monte Carlo simulations are coupled with the local stress strain approach for fatigue to obtain distributions of service loading. Fatigue life estimates based on the original loading histories are compared to those obtained from statistical descriptions of exceedance diagrams.

Providing confidence in life-cycle inventories (LCI) is dependent on being able to understand the source and extent of uncertainties in data and in the results produced with the data. From a situation several years ago of nearly no methodology for data quality considerations to a future where sophisticated data modeling approaches allow decision makers to obtain quantitative indications of the differentiability of alternatives, the science and art of data quality assessment are advancing rapidly. This paper provides perspective on why and how data quality issues are critical to successful implementation of LCI results and an overview of how practitioners are responding to the need for enhanced data quality assessment procedures. These procedures range from incorporation of individual data quality indicators to statistically-based models for estimation of parameter distributions. Careful consideration of data quality can markedly improve the interpretation and utility of LCIs.

Car manufacturers spend steadily increasing efforts to design cars in such a way that material selection, production steps, use and recycling, respectively disposal, fulfill environmental expectations and requirements to an optimal, best known extent. The additional application of Life Cycle Assessment (LCA) for car design supports a better and virtually “objective” understanding about resource consumption and environmental impacts during the complete life cycle of cars. Thus, LCA opens a high potential to contribute for future cars to improve them in terms of ecology as well as with regard to technological and even economic aspects. Holistic Life Cycle Costing (LCC) can hereby serve in a useful complementary manner. Co-operating with experienced partners and taking part in the development of LCA standards, Mercedes-Benz is developing LCA as a supporting tool for vehicle design.

Engineering components made by combining metals with plastic are not only lighter, stiffer and stronger but also cost effective to produce. Parts with complex geometry and attractive surfaces can be produced using this innovative hybrid technology developed by Bayer. Recycling these components is easy to accomplish due to the unique characteristics of the hybrid technology.

Since about 8 years the PE Product Engineering GmbH has a cooperation with the Institute for Polymer Testing and Polymer Science of the University of Stuttgart. Together they had been investigating automotive parts, structures and cars during their life cycle with many of the European automobile producers and their suppliers. Therefore energy-, raw material-, emissions-, waste-, waste water- and cost analysis have been made. A new generation of tires will be characterized by reduced rolling resistance that results in a lower fuel consumption during the usage phase and for this reason the overall system achieve a better environmental performance. This paper will show how Life Cycle Engineering works to meet the technical, economic and environmental requirements.

Life cycle benefits of a fully integrated thermoplastic instrument panel (IP) are compared to a traditional steel lattice construction. Design, manufacture, use and end-of-life phases are reviewed and presented in a life cycle management methodology. All components and processes are reviewed in a design for “X” format (i.e., recyclability, assembly, separability, disassembly, etc.) The IP objectives that were balanced include: design implications; feature content; consumer appeal; occupant energy management; quality, warranty, and NVH performance; design flexibility, materials of construction; weight savings and time to market. This methodology has been found useful to examine complex systems to guide decision makers in optimizing total life cycle costs.

Transportation, with its high energy consumption, is commonly recognized as a major contributor to local, regional, and global environmental impacts. With around 95% of transportation energy originating from petroleum and an increasing emphasis on the associated environmental impacts, alternative transportation fuels are receiving great attention from industry, government, researchers, and the public. When the motivation for developing alternative fuels is to reduce environmental impact, a rigorous tool is needed for comparing the effects of very different alternative and conventional fuels. Such an evaluation tool must consider not only the effects of fuel combustion, but also the effects of producing, refining/processing, distributing, and disposing of wastes associated with that fuel… in other words, the life cycle effects of the fuel.

The aim of this article is to show how Life Cycle Assessment (LCA) is used at PSA Peugeot-Citroën. The encountered difficulties and its limitations are emphasized regarding a practical example: end-of-life scenarios of a polypropylene bumper skin. The step evaluating the environmental impacts from the inventory results is particularly developped.

There are key considerations that need to be addressed when designing life-cycle assessment (LCA) studies with the purpose of providing input into making environmental superiority or equivalence claims or public policy decisions. For example, studies intended to be used in support of a public claim, about the superiority or equivalence of one product system over another, should follow specific requirements to ensure comparability of data and systems. The purpose of this paper is to describe methodological considerations, including critical review of an LCA study, which are key to the successful application of LCA for environmental superiority or equivalence claims and policy-making, and to present recommendations as to the appropriate use of LCA today.

The developing field of life cycle assessment is influenced by a multitude of environmental, economic, societal and cultural factors. The pace of change in the field masks the emerging consensus on the methodologies and common factors that influence life cycle assessment and give birth to life cycle management. This paper is designed to extract the trends from the developing field and present the concepts and structure of the state-of-the-art life cycle management techniques as they apply to business decision-makers.

Life-cycle analysis forces long-range planning, total cost visibility, enables a better understanding among different system components, helps identify alternate designs, and allows for effective, environmentally conscious manufacturing procedures. This paper will highlight the phases of a product life-cycle and the associated, product based cost models and environmental assessment for each phase. With this breakout of costs and assessment, indices and measures will be discussed which aid to optimally determine the most favorable options in designing for total product life-cycle.