Fullscale Two-Car Impact Test: A Comparison of Measured and Model Results

Abstract

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. INTRODUCTIONThe Federal Railroad Administration's Office of Research and Development, with the assistance of the Volpe Center, has been conducting research studies on the crashworthiness behavior of conventional and modified passenger rail equipment. The goal of these studies is to enhance the safety of both passengers and crewmembers in the event of a derailment or collision. Work conducted for these studies includes the development of analytical models as well as scaled and fullscale testing. Examples of the models developed include: detailed three dimensional non-linear large deformation finite element crush models used to investigate the crush behavior of equipment and lumped parameter models to study the collision dynamic behavior of single cars, connected cars, and complete consists. The fidelity of the modeling approaches has been demonstrated by the close agreement of predicted responses with measurements taken from full-scale testing [1,2,3] for key test parameters.As part of this research, a series of tests are being carried out to compare the crashworthiness performance of conventional equipment and the performance of improved crashworthiness equipment [4]. The measurements made during these tests also allow the refinement of analytical models. As a result these refined models can predict the crashworthiness of trains with increased fidelity [5,6].A rigid barrier impact test was conducted on two coupled conventional Budd Company Pioneer rail...

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“…Related research has proven that developing and using a multibody dynamics model, as opposed to a traditional finite element model, can save substantial computation time. [21][22][23][24][25] Scaled model tests have been widely used in ship designing, aerospace industry, bridge structure engineering, traffic design, bullet explosion shock analysis, bridge and tunnel deformation failure analysis and other engineering problems. Simplified small-scale model motor coaches have been designed and tested under both static and dynamic loading, and attempts were made to relate the results to a full-scale collision by Lowe et al 26 Barley and Mills 27 and Kao and Chan 28 conducted an automobile model test at scales of 1/10 and 1/2 to study the automobile crashworthiness.…”