Authors: David C. Tyrell, Eloy E. Martinez, Tomasz Wierzbicki

Date of Publication:  November 1999

Sponsoring Agency:  U.S. Department of Transportation - Federal Railroad Administration - Office of Research and Development

Performing Organization:  USDOT Volpe National Transportation Systems Center; Impact and Crashworthiness Laboratory - Massachusetts Institute of Technology

Report No:

Abstract:

This paper investigates the parameters that influence the structural response of typical wide nose locomotive short hoods involved in offset collisions. This accident scenario was chosen based upon the railway collision that occurred in Selma, North Carolina, on May 16, 1994. A raised overhanging intermodal trailer on a freight car struck the front of the oncoming passenger locomotive. The objective of the study is to determine the current baseline level of crashworthiness of locomotive hood structures and the potential effectiveness of stronger corner structures. The key issues addressed are: degree of overlap, material and thickness combinations, obliquity, and crush response dependence on initial impacting speed. For a raised offset collision where the intruding body is far away from any support structures, an analytical expression is developed to predict the mean crush force. Comparisons of the results with finite element calculation are favorable. The scenarios involving obliquity, and different initial impacting speeds are investigated using non-linear large deformation finite element analyses. Key results are: obliquity has little effect on the mean crush force for short penetration distances; increased material thickness improves crashworthiness performance; initial impacting speed does not dramatically alter mean crush loads predicted for large offsets away from supports; and the distances from supporting structures have a significant effect of the predicted mode of failure and hence predicted mean crush loads. The results of the study
show that it is possible to dramatically increase the crashworthiness responses of short hood structures with minor increases in weight while staying within the original design volume envelope.
 

No. of Pages:   15