Biofidelity requirements for the THORAX project
Biofidelity requirements are to be used to ensure that a crash test dummy loads the vehicle and restraint system in an accident in a similar way to the human, and to ensure that the response of the dummy to this loading is relevant to the prediction of injury risk in simulated crashes that are representative of real-world accidents. The main aim of this deliverable is to provide a set of biofidelity requirements for the thorax and shoulder for evaluation of an advanced frontal impact crash test dummy.
This report has reviewed existing thorax and shoulder biofidelity requirements for frontal crash test dummy evaluations. The load cases used in these requirements were compared to the loads in actual collisions. It was identified that inclusion of additional requirements in which the thorax is exposed to various types of distributed and belt-only loads would be beneficial.
To identify additional tests, post mortem human subject data and volunteer data were reviewed and test conditions and available data documented. Inclusion criteria used to assess e.g. the quality of documentation of a data set, or the representativeness of the subjects that were tested, were established. Using these criteria the reported test conditions and results were analysed with the target to specify biofidelity requirements and engineering guidance for the design of an enhanced dummy shoulder-thorax complex. None of the available datasets were ideal for specifying biofidelity requirements for frontal impacts in modern restraint systems as available in the market now. These systems typically include belt pretensioning and force-limiting and carefully combined belt and airbag contributions to the occupant protection. Instead a broad set of requirements has been used in an attempt to capture biofidelity under various restraint system types and load conditions. It is hoped that a dummy with a good level of biofidelity throughout this broad range of conditions will still demonstrate an appropriate level of biofidelity in modern restraint systems and common crash conditions.
The biofidelity requirements document a well-defined set of test conditions and the dummy responses that are required in those loading conditions. The engineering guidance includes biomechanical data that will be used to define relative - rather than absolute - targets for dummy performance. These relative targets are useful to guide the design of an enhanced dummy.
Various methods used to normalise the response data to that of a standard size of subject or scale data to other sizes were reviewed, benefits and limitations discussed and recommendations were made.
Finally, a set of biofidelity target corridors for the 50th percentile male are presented in the Appendix B to Appendix K.