Fullscale two-car impact test: a comparison of measured and model results

The Volpe National Transportation Systems Center is conducting research into the crashworthiness of rail vehicles in support of the Federal Railroad Administration´s Office of Research and Development. The approach taken has focused on the review of accidents, development of analytical tools and performing full-scale testing. A series of inline full-scale impact tests have been performed using conventional passenger cars. Recent full-scale testing included two instrumented coupled conventional passenger cars impacting a fixed barrier at 26 mph. The cars were instrumented with accelerometers, strain gages and string potentiometers. From these measurements, car translations, rotations, relative displacements and coupler forces were calculated. A rigid body dynamics model of the two-car configuration was developed and used to design the test. In order to improve the collision dynamics models of passenger cars, the results from this test are being used to refine that model. This paper describes the two-car impact test, the reduction of data collected during the test and the refined collision dynamics model. Post-test refinements allow the model to more accurately simulate the vertical and lateral motions of the cars, including the timing of the lateral buckling of the cars. The post-test model also more accurately simulates the climbing of the impact car as it crushes. Comparisons between the refined model results with the measured data are presented for the motion of the center of gravity of the cars, coupled car interactions and forces, and lateral buckling.