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One way to improve vehicle's fuel economy is to reduce its weight. Reducing weight, however has other consequences. One of these is reduced vehicle size. Almost invariably, lighter vehicles are smaller. Reducing vehicle weight has also been associated with a reduction in occupant protection; the lighter the vehicle, the greater the chance of injury when a crash occurs. For this study, a data-based model is used to evaluate the independent effects of size and weight. This model is constructed using the NASS database and information obtained from NCAP tests. The results indicate that although mass is the dominant factor, size also has an effect; some of the observed reduction in safety benefits associated with mass reduction is actually an effect of size reduction. The model is also used to evaluate the effects of varying stiffness.

Deployment of an airbag or charging of a tank by an inflator-canister system is a highly dynamic process. Quantification of energy storage, energy flux, work done, flow rates, thermodynamic properties, and energy conservation are essential to describe the deployment process. The concepts of available work and entropy production are presented as useful parameters when evaluating airbag aggressivity from tank test results for different types of inflators. This paper presents a computational methodology to simulate a pyro- and a hybrid-inflator-canister-airbag system to predict the force pattern that could occur on an out-of-position occupant when the airbag deploys. Comparisons with experimental data have been made in all cases where data were available. These include driver-, passenger-, and side-airbag designs.