Study of Vehicle Dynamics and Occupant Response in Side Impact Crash Tests
Side impact crash is a leading cause of fatalities on the roadways of the industrialized world. In the mid 1990's NHTSA implemented a new car assessment program testing the lateral crashworthiness of vehicles entering the market with a moving deformable barrier. Previous work has been done in an attempt to distill these tests into finite element simulations using specific vehicle test results; however there has not been a comprehensive study attempting to develop a model that includes a large number of tests to evaluate trends in vehicle kinematics and how they affect the occupants coupled with finite element simulations. To this end, a study of side NCAP tests was performed on all sedan cars based on the test results reported in the NHTSA Vehicle Crash Test Database since the introduction of the 2005 model year. This data was used to evaluate typical motion of the target vehicle during a regulatory crash test, and the corresponding occupant response. This sample consisted of new models entering the market and nameplates with major redesigns with a sample size of 72 vehicles. From these tests a series of velocity profiles were developed including time versus average velocity plots for vehicle center of gravity, door sill, driver's seat and driver door. These parameters have been shown to be important in occupant response and injury. There was significant variability in the response at several accelerometer locations. It was also found that rotation of the vehicle did not become significant until after 100 ms, after the maximum injury was predicted by the dummy. A parametric finite element analysis was performed using the both the USSID and ES-2re models to study the response of a restrained occupant during a typical crash test. These simulations showed that the velocity of the intruding door had a large effect on the thoracic injury predicted by the side impact dummy models. The full text of this paper may be found at: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv21/09-0016.pdf For the covering abstract see ITRD E145407.
Comparison of ES-2re with ES-2 and USSID Dummy - Considerations for ES-2re model in FMVSS Tests
For almost 2 years the ES-2 dummy is used to predict occupant injury risk in side impact crashes in EURO-NCAP. Recently, NHTSA announced that a modified version of the ES-2, the ES-2re is likely to substitute the USSID in the FMVSS 214. Hence, the knowledge gained with the ES-2 might be also useful to design cars in accordance with the regulation FMVSS 214. The paper discusses various simulations to investigate the behavior of the models. One emphasis is to penetrate if and under which circumstances the ES-2re dummy behaves different from the ES-2 and if the modeling technique for the ES-2 model is sufficient to achieve accurate results for the ES-2re dummy. The simulations contain simple rigid barriers as well as sub models using a detailed seat model and the deformable door and b-pillar. Another emphasis is a comparison between the ES-2re and the USSID model in barrier tests. Finally, results of the ES-2re and the USSID model from a vehicle side crash simulation are compared.
COLLISION PERFORMANCE OF AUTOMOTIVE DOOR SYSTEMS
Historically, most safety related improvements to door systems have involved retention of occupants within the vehicle. However, such improvements have not been without some safety trade-offs. The recent update to FMVSS 214 (Side Impact Protection) has focused attention on increased occupant protection in side impacts. The standard essentially increases vehicle side strength requirements in order to reduce intrusion into the occupant space. The safety consequences associated with strengthening vehicle side structure will be evaluated with respect to various impact configurations. Energy management considerations of current as well as conceptual door systems during a collision will also be discussed. Individual latch and hinge component testing as currently required by FMVSS 206 does not completely evaluate the collision performance of the door as a system. From field collision evaluation, it has been seen that doors and surrounding side structure must act as a system to efficiently manage collision forces and distribute occupant loads. Procedures for evaluating current and future door systems by means of revised laboratory testing procedures will be evaluated. (A) For the covering abstract see IRRD 874898.