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Two widely used computer programs developed for the analysis of vehicle collisions are CRASH and SMAC. This paper reviews stiffness parameters which are used in the application of these programs, and methods to select these parameters. The paper also introduces a rational method to select stiffness parameter KV for the SMAC program. The CRASH program expresses the vehicle force-crush relationship as FC = A + B*CR, where FC is the force per unit width, and CR is the vehicle residual crush. The “stiffness parameters,” A and B, define a linear relation with a zero-crush intercept. For collinear impacts, these parameters are used in determining crush energy, which in turn is used in determining changes in velocities of the impacting vehicles. Over the years, considerable effort has been expended by numerous researchers to determine A and B for a variety of vehicles, and a substantial body of vehicle crash test data has been developed and analyzed to this end.

Testing methods and SAE Recommended Practices were developed for evaluating both the ability of a truck cab to resist roof loading in a rollover environment and the occupant kinematics and injury potential for occupants in a 90-degree heavy truck rollover. In evaluating a heavy truck roof for its ability to resist rollover loads, real-world accident data was analyzed and full-scale tests were performed to define the rollover environment. It was found that testing methods currently in place for passenger cars were not sufficient to represent the loading mechanisms that typically occur in a heavy truck rollover. An SAE Recommended Practice (RP) for both dynamic and quasi-static roof load testing was developed, and tests were conducted to evaluate their use. To evaluate heavy truck occupant safety in a 90-degree rollover, independent of roof intrusion, a rollover simulator was developed. The simulator allows occupant restraints, seats, and interiors to be evaluated for injury mechanisms.

This paper describes a straight-forward, automated approach to performing sensitivity analyses using Monte Carlo simulation techniques. Probability distributions are assigned to key input parameters, and results are expressed in the form of probability distributions of each of the desired output parameters. With this technique, it is possible to obtain quantitative results regarding the probability of results being within selected ranges. The approach is fast and automated, and provides a rational basis for dealing with uncertainty and ranges of parameters in accident reconstruction analyses.

This report presents two test methods and results of a study involving unrestrained dummies in dynamic rollover tests. Data are presented showing dummy head kinematics in relation to the interior of the vehicle as the vehicle experiences deceleration prior to the trip.

Testing techniques for creating rollovers have been a subject of much study and discussion, although previous work has concentrated on creating a repeatable laboratory test for evaluating and comparing vehicle designs. The two testing methodologies presented here address creating rollover tests that closely mimic a specific accident scenario, and are useful in accident reconstruction and evaluation of vehicle performance in specific situations. In order to be able to recreate accidents on off-road terrain, a test fixture called the Roller Coaster Dolly (RCD) was developed. With the RCD a vehicle can be released at speed onto flat or sloping terrain with any desired initial roll, pitch and yaw angle. This can be used to create rollover collisions from the trip stage on, including scenarios such as furrow trip on an inclined road edge.