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Understanding the lightweighting potential of materials is important in making strategic decisions for material selection for a new vehicle program. Frequently benchmarking is done to support these decisions by selecting a reference vehicle which is believed to be mass efficient, then using the teardown mass data to set targets for the vehicle under design. In this work, rather then considering a single benchmark vehicle or a small set of vehicles, we looked at a large sample of vehicles over a range of sizes and segments (approximately 200 vehicles). Statistical methods were used to identify mass drivers for each subsystem. Mass drivers are the attributes of the vehicle and subsystem which determine subsystem mass. Understanding mass-drivers allows comparisons across vehicle size, segments, and materials. Next, we identified those vehicles which had subsystems which were much lighter than the average after adjusting for mass drivers. This set was defined as mass-efficient designs.

It is well known that an unplanned component mass increase during vehicle design creates a ripple effect of changes throughout the vehicle subsystems, which require resizing for the additional mass. This in turn, increases overall vehicle mass. And the opposite is true in vehicle mass reduction where subsystem resizing is necessary to account for an initial mass reduction enabled, for example, by a new technology. These secondary mass changes can be significant and must be considered in the mass budgeting process due to their importance to fuel consumption and greenhouse gas emission assessments. Secondary mass reduction may be modeled using subsystem mass influence coefficients-the incremental change in subsystem mass for a unit change in gross vehicle mass. This paper focuses on means to estimate influence coefficients using two methods: Analytical and Regression.

Nyquist plots are a classical means to visualize a complex vibration frequency response function. By graphing the real and imaginary parts of the response, the dynamic behavior in the vicinity of resonances is emphasized. This allows insight into how modes are coupling, and also provides a means to separate the modes. Mathematical models such as Nyquist analysis are often embedded in frequency analysis hardware. While this speeds data collection, it also removes this visually intuitive tool from the engineer’s consciousness. The behavior of a single degree of freedom system will be shown to be well described by a circle on its Nyquist plot. This observation allows simple visual examination of the response of a continuous system, and the determination of quantities such as modal natural frequencies, damping factors, and modes shapes. Vibration test data from an auto rickshaw chassis are used as an example application.

This book provides readers with a solid understanding of the principles of automobile body structural design, illustrating the effect of changing design parameters on the behavior of automobile body structural elements. Emphasizing simple models of the behavior of body structural systems rather than complex mathematical models, the book looks at the best way to shape a structural element to achieve a desired function, why structures behave in certain ways, and how to improve performance.

This book provides readers with a solid understanding of the principles of automobile body structural design, illustrating the effect of changing design parameters on the behavior of automobile body structural elements. Emphasizing simple models of the behavior of body structural systems rather than complex mathematical models, the book looks at the best way to shape a structural element to achieve a desired function, why structures behave in certain ways, and how to improve performance. This second edition of Fundamentals of Automobile Body Structure Design contains many new sections including: the treatment of crashworthiness conditions of static roof crush and the small overlap rigid barrier torsion stiffness requirements material selection illustrations of body architecture Each chapter now includes a clear flow down of requirements following the systems engineering methodology.