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.
Door velocity and occupant distance affect lateral thoracic injury mitigation with side airbag.
The relationship between thoracic injury risk and parameters of door velocity and occupant distance was delineated in blunt lateral impact with side airbag deployment. A sled impact model was exercised with the validated MADYMO fiftieth percentile facet occupant model and a generalized finite element torso side airbag. Impact velocity was incremented from 4.0 to 9.0m/s; occupant-airbag distance (at time of airbag activation) was incremented from 2.0 to 24.0 cm; simulations without airbag were also examined. Using compression, deflection rate, and the Viscous Criterion, airbag performance was characterized with respect to occupant injury risk at three points of interest: occupant distance of most protection, distance of greatest injury risk, and the newly defined critical distance. The occupant distance which demonstrated the most airbag protection, i.e., lowest injury risk, increased with increasing impact velocity. Greatest injury risk resulted when the occupant was nearest the airbag regardless of impact velocity. The critical distance was defined as the farthest distance at which airbag deployment exacerbated injury risk. This critical distance only varied considering chest compression, between 3 and 10 cm from the airbag, but did not vary when the Viscous Criterion was evaluated. At impact velocities less than or equal to 6m/s, the most protective occupant location was within 2 cm of the critical distance at which the airbag became harmful. Therefore, injury mitigation with torso airbag may be more difficult to achieve at lower ΔV.
The alcohol-aggression stereotype: a cross-cultural comparison of beliefs.
University students (N = 1,008) in eight countries participated in a survey aimed at mapping cross-cultural alcohol expectancies. Multisample structured means analysis was applied to compare changes in aggressive behaviors believed to occur in connection with drinking after "many" alcoholic drinks. Most subjects expressed the belief that intoxication was associated with greater aggressiveness, but there were significant national differences unrelated to self-reported alcoholic beverage preference, frequency of drinking to intoxication, or rates of personal involvement in episodes of alcohol-related aggression. Thus, the expectation that drinking leads to aggression may be determined to a significant extent by contextual factors and cultural traditions related to alcohol use.