In a 2012 paper, Brach, Brach, and Louderback (BBL) investigated the uncertainty that arises in calculating the change in velocity and crush energy with the use of the CRASH3 equations (2012-01-0608). They concluded that the uncertainty in these values caused by variations in the stiffness coefficients significantly outweighed the uncertainty caused by variations in the crush measurements.This paper presents a revised analysis of the data that BBL analyzed and further assesses the level of uncertainty that arises in CRASH3 calculations. While the findings of this study do not invalidate BBL's ultimate conclusion, the methodology utilized in this paper incorporated two changes to BBL's methodology. First, in analyzing the crash test data for several vehicles, a systematic error that is sometimes present in the reported crush measurements was accounted for and corrected. This systematic error arises when a vehicle's plastic bumper fascia rebounds more than the underlying structure, creating an air gap and causing the reported crush measurements both to underestimate the actual deformation and to exhibit more scatter than they otherwise would. This scatter translates into uncertainty in the stiffness coefficients.Second, linear regression was used to obtain the stiffness coefficients and to quantify their uncertainty. Instead of using linear regression, BBL assumed the same damage onset speed (b0) for each crash test. In essence, this means that BBL assumed a value for one of the stiffness coefficients, with the only variability in that coefficient coming from the differences in vehicle weights from test to test. The methodology employed in this paper eliminated the need to assume a damage onset speed.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Further Assessment of the Uncertainty of CRASH3 ΔV and Energy Loss Calculations


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE 2014 World Congress & Exhibition ; 2014



    Publication date :

    2014-04-01




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Further Assessment of the Uncertainty of CRASH3 Delta V and Energy Loss Calculations

    Rose, N.A. / Carter, N. / Society of Automotive Engineers | British Library Conference Proceedings | 2014


    Uncertainty of CRASH3 ΔV and Energy Loss for Frontal Collisions

    Louderback, Andrew / Brach, R. Matthew / Brach, Raymond M. | SAE Technical Papers | 2012


    Uncertainty of CRASH3 Delta V and Energy Loss for Frontal Collisions

    Brach, R.M. / Louderback, A. / Society of Automotive Engineers | British Library Conference Proceedings | 2012


    2012-01-0608 Uncertainty in CRASH3 Delta V and Energy Loss for Frontal Collisions

    Brach, R.M. / Louderback, A. / Society of Automotive Engineers | British Library Conference Proceedings | 2012


    Inaccuracies in the CRASH3 Program

    Wolley,R.L. / Warner,C.Y. / Tagg,M.D. et al. | Automotive engineering | 1985