Search Results

Pre-crash safety systems are reversible systems that are deployed in a vehicle when external and internal sensors determine that a crash is likely. This paper provides a preliminary estimate of the effect of such systems in reducing the number and the severity of injuries to automobile occupants in traffic accidents. These estimates are obtained by combining test data for pre-crash system response with the statistical information on vehicle crashes available in NASS-CDS database for years 1996-2007. It is observed that significant reductions in the number and the severity of occupant injuries may be achievable by pre-crash systems that include pre-crash braking enhancements and seatbelt pre-tightening actions.

The development of a mobile deformable barrier (MDB) for use as a passenger car surrogate in car-to-LTV impacts is examined here. Since data from crash tests are subject to variations in vehicle properties as well as variations in test configurations, it is likely that repeated identical tests utilizing nominally identical vehicle pairs will yield different results due to these variations. It is necessary to account for the above variations and the resulting response corridor in developing vehicle surrogates if these surrogates are to be used for evaluating compatibility. Results are presented here for the ‘response corridor’ of a medium size passenger car, obtained from finite element simulation of car-to-LTV impacts with defined variations in the input parameters. An MDB concept is then developed to represent this ‘response corridor’ in impacts with LTVs.

The essential concepts for developing a moving deformable barrier that may serve as a vehicle surrogate in assessing vehicle compatibility are described in this paper. Although moving deformable barriers have been used for assessing other safety criteria, their purpose in those cases is to reproduce a limited set of responses in the struck vehicle. An MDB for vehicle compatibility however, needs to be able to reproduce the responses of both the vehicles. The present study describes the concept of developing such barriers by generating ‘response corridors’ for the significant variables by nonlinear finite element simulations and then selecting design parameters such that the MDB response is within this corridor. It is observed that the response of the equivalent MDB representing a light truck vehicle is reproducible when response corridors are utilized.

The concept of height of force has been suggested by some researchers as one possible parameter defining the structural interaction probability between vehicles of different sizes. This proposed parameter was defined as the vertical centroid of forces exerted on a flat barrier surface when a vehicle crashes into the barrier. It is therefore measured as a function of elapsed time since crash. In this paper, the height of force is obtained from theoretical calculations and also measured in crash tests at 56 km/h against barriers instrumented with an array of load cells. It is observed that the measured values of height of force have significant errors which are dependent on factors other than the crash conditions and the properties of the vehicle's structure and geometry. These factors need to be taken into account in future discussions of using the height of force or the average height of force as an indicator of vehicle compatibility.