The chair invited the audience to discuss the issue. Discussion came up on when the rebound phase starts. Mr. Zander confirmed on request of Mr. Roth that the interval should be considered in which the FlexPLI behaves like the human or the human model respectively. Dr. Ries pointed out that then the interval proposed seems much too long since the legform is only for the first contact confirmed to be biofidelic. Also, this period may be different for tibia and knee. He and Mr. Roth wondered how BASt specified the length of their Biofidelic Assessment Interval and Mr. Zander responded that an objective method and automatic evaluation method was requested. There is no clue that the impactor biofidelity is limited to the pure contact phase with the vehicle only. The BAI can solve this issue. In addition, it covers all potential critical loadings during the test. Partly, the BAI interval is even shorter than the interval proposed by industry in document GTR9-5-30. This was demonstrated in document GTR9-6-07. The secretary reminded the attendees that some information on this had also been shown in the TF-BTA meeting held on 18 March 2013 and that the information is already available on the website. (Note of the secretary: The documents referred to were presented in the 3rd meeting of the Task Force Bumper Test Area as documents TF-BTA-3-03, TF-BTA-3-07 and TF-BTA-3-08 and are available on the respective UNECE website.)
21. Mr Roth presented document TF-BTA-03-03 comparing some simulations done with the FlexPLI and the Total Human Model for Safety (THUMS). [Note of the secretary: The document shown was supplemented by some videos. Mr Roth kindly provided an extended version of his presentation afterwards for publication on the Task Force’s website that adds some sketches of the respective impactor behaviour. This document is available as TF-BTA-03-03/Rev.1.] He explained that the FlexPLI, compared to the THUMS, well reflects the behaviour in two dimensional testing but that clearly deviates from the THUMS when hitting curved shapes. He concluded that the impactor behaves not biofidelic in those areas.
22. Mr Broertjes thanked Mr Roth for the work. He was wondering whether it would possible to e.g. replace one THUMS leg by the FlexPLI – so to say using the FlexPLI as prosthesis for the THUMS. This may provide more complex information on the biofidelity of the FlexPLI at more outside positions. It was noted that, however, there may be different codings used for the two simulation models that could prevent this to be done. Also, it is most likely a huge amount of work since the proper functioning of this new model would need to be validated. Mr Knotz confirmed this assessment from his experiences with the simulation models.
23. Mr Stammen asked what the behavior is at the vehicle centreline and it was confirmed that the 2D testing does not seem to be an issue. Mr Hardy wondered whether the effects would be the same at the other car side: the standing position of the leg of the THUMS may influence the test result. Mr Roth answered that this was not considered in this part of their company internal study but that the differences between FlexPLI and THUMS will remain. Mr Gehring added that the behavior may vary at different positions and that according to his opinion clearly the mass of the upper body is missing which may change things.