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A Method for Quantifying Vehicle Crush Stiffness Coefficients

James A. Neptune, George Y. Blair, and James E. Flynn

Blair, Church & Flynn Consulting Engineers

ABSTRACT

The accuracy of an accident reconstruction, which employs the damage, analysis feature of the CRASH3 computer program, is directly related to the accuracy of the crush stiffness coefficients employed. Crush stiffness coefficients, however, are available only through a limited number of publications and for a limited number of vehicles. In addition, assumptions made in the determination of these published stiffness coefficients bring their accuracy into question and, as a result, limit their value to a reconstructing engineer. It is concluded, therefore, that an engineer must use a critical eye when viewing the results of a CRASH3 reconstruction in which these stiffness coefficients were employed.

A method is set forth for quantifying stiffness coefficients from crash test data available in a databas.

e which can be obtained from the National Highway Traffic Safety Administration (NHTSA). This method will allow reconstructing engineers to have a greater level of confidence in the results of an accident reconstruction in which the damage analysis feature of CRASH3 is employed.

*The numbers in the brackets refer to references listed at the end of the paper.