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Crash Testing and Simulation of Passenger Trains
There is an ongoing research program in the United States to investigate and improve rail equipment crashworthiness. As part of this effort, computer models have been developed and applied to determine the crash response of rail equipment. Comparison of the model predictions with full-scale test results is required to validate the models. A corresponding series of full-scale rail vehicle crash tests are being performed as part of the rail crashworthiness research effort. The first full-scale test, an impact of a single passenger coach car into a fixed wall, was conducted at the Transportation Technology Center in Pueblo, Colorado on November 16, 1999. The test consisted of a single Pioneer car traveling at 35.1 mph when it impacted the wall.
The objectives of this test were to determine the failure modes of the major structural components, to measure the gross motions of the car, to measure the force/crush characteristic, and to evaluate selected occupant protection strategies. The condition of the test vehicle, both before and after the collision, is shown in Figure 1.
Our involvement included documenting the vehicle after the collision to determine the modes of deformation, postprocessing the recorded test data, and simulating the crash test with a detailed finite element model.
A detailed documentation of the test vehicle was performed to understand the failure modes and damage propagation within the vehicle structure. Also, undocumented details of the car structure were captured for making an accurate FEA model. The documentation was performed primarily through engineering sketches and through digital photography. Figure 2 shows sample sketches made during the postmortem. Figure 3 shows complementary photos.
Using the details from the vehicle postmortem described above, a detailed Finite Element Analysis (FEA) model was made, which contained approximately 500,000 elements. LS-DYNA3D was used to solve the problem, taking approximately 100 hours to solve 0.5 seconds worth of simulation on a 4 processor SGI Origin 200. Figure 4 below describes the generated FEA model.
The major structural element was the draft sill. It's predicted collapse, shown in Figure 5, closely resembled the failure mode seen on the test vehicle.
Figure 6 shows some comparisons between test data and calculated data.
Movie 1 shows the calculated response of the vehicle as it hits the wall. The lifting of the front truck as the end structure collapses closely matches the behavior seen during the test.
References:
MacNeill, R.A. and Kirkpatrick, S.W., "Vehicle Postmortem and Data Analysis of a Passenger Rail Car Collision Test," Proceedings of: JRC2002, The 2002 ASME/IEEE Joint Rail Conference, Washington D.C., April 23-25, 2002.
Abstract
Kirkpatrick, S.W. and MacNeill, R.A., "Development of a Computer Model for Prediction of Collision Response of a Railroad Passenger Car," Proc. JRC2002, The 2002 ASME/IEEE Joint Rail Conference, Washington D.C., Apr. 23-25, 2002.
Abstract
D. Tyrell, K. Severson, and A.B. Perlman, "Single Passenger Rail Car Impact Test Volume I: Overview and Selected Results," U.S. Department of Transportation, DOT/FRA/ORD-01/02.1, March 2000.
The above analyses were performed using LS-DYNA developed by the Livermore Software Technology Corporation (LSTC).
LS-DYNA - General Purpose Transient Dynamics Finite Element Program.
For inquiries or comments, please contact:
Dr. Steven Kirkpatrick
Principal Engineer
e-mail: skirkpatrick@ara.com
Dr. Robert T. Bocchieri
Principal Engineer
e-mail: rbocchieri@ara.com
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Figure 1
Crash Test PhotosTest Vehicle Pre- and Post-Test.
Figure 2
Sample Postmortem Sketches Documentation of Crash Damage with Engineering Sketches.
Figure 3
Sample Postmortem Photos
Documentation of Crash Damage with Photos.
Figure 4
Pioneer Car FEA Model
500,000 Element Pioneer Car Model: End Structure Detail.
Figure 5
Draft Sill Collapse Simulated Draft Sill Response from FEA Model.
Figure 6
Data Comparison
Test and Simulation Data are Compared.
Movie 1
Single-Car Crash Simulation
Pioneer Passenger Car Impacting a wall at 35 mph.
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