MADYMO occupant simulation IMPORTANT issues

Topics related to collision & Trajectory analysis formerly on our 'Registrants only' area however which we get asked about frequently so believe shoud be in the open forum too
Post Reply
MSI
Site Admin
Posts: 1302
Joined: Thu Jun 18, 2009 12:37 pm

MADYMO occupant simulation IMPORTANT issues

Post by MSI » Wed Oct 16, 2019 4:43 pm

Q: Do you use or have you evaluated any MADYMO applications in litigation cases?

A: Yes. And one case in particular, from a few years ago, we evaluated an expert report who used the MADYMO occupant simulation program to evaluate injury potential in a low speed collision.
This post is to demonstrate that ANY and ALL occupant simulation needs to be carefully evaluated.
EVERY HUMAN is different!
  • For any case specific application of ANY occupant simulation approach:
    • Use and/or evaluate with extreme caution!
Occupant simulation models come in several flavors, however ALL are based on or direct derivatives of the ATB program: Here are the conclusions from the case where we evaluated a MADYMO appliction (Note NAMES AND DATES REDACTED):
  • Summary and Conclusions
    In summary, the authors of the EXPERT report did not properly perform a scientific investigation or reconstruction of the subject accident. They provided arbitrary and speculative opinions based on limited and incomplete information, they did not use or reference any current techniques to reconstruct a collision like the subject accident, they included arbitrary calculations of impact duration and range of speed with no scientific basis.
    The authors of the EXPERT report then used their opinions as the basis to perform a 3D occupant simulation of OCCUPANT in the subject collision.
    The authors of the EXPERT report utilized the MADYMO 3D simulation model with the following deficiencies:
    • They did not properly create an acceleration substantially similar to the acceleration in the subject accident.
    • They did not properly create and include any provisions for the interior of the Jeep with seat, floor, dash, center console, B pillar and side glass substantially similar to the vehicle at the time of the collision.
    • They did not properly create a 3-point restraint system substantially similar to the belt in the vehicle at the time of the accident.
    • They did not properly create inputs to model OCCUPANT and place her in a position and orientation for their MADYMO simulation that was substantially similar to the position and orientation of OCCUPANT at the time of the impact (i.e., turned to left in preparation for making a right turn).
    Any results or conclusions drawn from their arbitrary and speculative MADYMO 3D occupant simulation related to detailed occupant kinematics involve so many approximations, estimates, and assumptions that they must be recognized as not being compatible with sound engineering practices and principles and, therefore, not scientifically supportable.
and here's the original report: For additional related information Please see:
  • What is the ATB?
  • pc-crash: Man rightfully Wins New Trial in Car-Accident Trial
    • The report from the case, filed with the court which includes the following important conclusions:
      • After over 55 years of research on occupant simulation there is no model in existence today which has been validated as a generally predictive model for detailed occupant kinematics in any type of real-world accidents.
      • Accident reconstruction programs and occupant simulation models are subject to limitations imposed by the mathematical idealizations and the simplifying assumptions inherent in any mathematical model of the physical world.
  • Validation for Occupant Simulation?
Question? Comment? Please email forum@mchenrysoftware.com. Also see the McHenry Forum Index
Visit McHenrySoftware.com for technical information & software.
(c) McHenry Software, Inc ALL Rights Reserved.

Post Reply