Mr Ammerlaan presented results of TNO active human model simulations of the effect of sitting height in side impact (PSI-07-11) and an overview of shoulder loading for the WorldSID 50th male (PSI-07-12).
Mr Wernicke presented a WorldSID 50th male shoulder assessment proposal (PSI-07-13). Mr Wernicke noted that engagement of the human shoulder joint is likely to provide a valid means of protecting the human thorax and noted results of NHTSA and ISO biofidelity testing which had shown the WorldSID 50th shoulder to be a very biofidelic part of the dummy. Shoulder force deflection responses were analysed from a variety of pendulum, sled and vehicle-to-pole side impact tests. The results showed the shoulder force would typically plateau between 2-2.5 kN across the 40-70 mm deflection range. This indicated the shoulder rib of the WorldSID 50th percentile male would not have the attributes to be misused as a non-biofidelic load path. Mr Wernicke suggested that a shoulder criterion should only need to be used to prevent excessive non-biofidelic shoulder loadings. Shoulder force was not considered suitable because of the nature of the shoulder force-deflection responses and deflection may not be suitable due to limitations of the shoulder IRTRACC. Mr Wernicke suggested the use of a rib stop which replaces the IR-TRACC in the WorldSID shoulder. Detection of peak force in the shoulder load caused by bottoming out on a rib stop could be used to detect excessive shoulder loadings.
Ms Versailles was concerned the addition of a shoulder rib stop could delay the WorldSID 50th male timeline and noted that the WorldSID group had agreed to freeze the dummy design for the PSI GTR during the meeting held the previous day.
Mr Belcher suggested that even for the most severe shoulder loadings it may be likely to take 40-50ms to bottom-out the shoulder anyway. This would typically leave no more than 10 ms in which high shoulder load could be used to offload the thorax in a non-biofidelic way. Otherwise the thorax deflection would typically have peaked anyway. It may therefore be extremely difficult, if not impossible to use the shoulder of the WorldSID to offload the thorax in a non-biofidelic way.
The issue of how removal of the IRTRACC might influence the shoulder biofidelity was also discussed. Ms Tylko confirmed that a number of the WorldSID 50th male biofidelity and injury criteria tests had been conducted without shoulder IRTRACCs. Ms Tylko offered to make a presentation at the next meeting showing that the shoulder IRTRACC can be removed without adversely affecting results.
ACTION: Transport Canada to provide information for next meeting on results of matched WorldSID 50th male side impact tests with and without a shoulder IRTRACC fitted.
Mr Hogan took the key point from Mr Wernicke’s presentation to be that the shoulder cannot really be unreasonably exploited as a load path and suggested a shoulder criterion may therefore not be required.
Mr Ammerlaan was not comfortable with not including a shoulder criterion in the PSI GTR, but was also not sure (at this stage) what the best shoulder criterion would be.
Ms Tylko agreed that a satisfactory criterion had not yet been developed.
Mr Wernicke asked to keep the shoulder criterion discussions open till the next meeting. Mr Wernicke and Mr Ammerlaan noted the matter was also being considered within EuroNCAP.
Mr Hogan stated he was open to leaving shoulder criterion discussions open, but that it would be necessary to have a solid proposal by the next meeting for anything to be included in the first phase of the GTR.
ACTION: Sub-group including Hans Ammerlaan, Steve Ridella, Philipp Wernicke and Thomas Belcher to consider possible shoulder injury criterion.