COMPUTER SIMULATION OF REAR IMPACTBIOMECHANICAL OCCUPANT RESPONSE PREDICTIONSFOR FRONT REAR SEATED PASSENGERS

摘要

Many variables, each with a wide parameter range, influence theperformance limits and occupant injury protection levels provided by a motor vehiclesafety system. Full scale crash tests offer one means to study safety systemperformance, but such tests are expensive and only provide limited data related to theinfluencing variables or factors. Commercially available occupant computersimulation codes, in conjunction with efficient 'multi-variable' analysis techniqueslike the '2-level factorial' method, offer a cost-effective means for 'multi-variable'evaluation of a given safety system. The current study uses a 'Articulated TotalBody' (ATB) computer code, with a 'high-low' (I.e. 2-level) 'factorial' method, tostudy 'multi-variable' effects of motor vehicle adult occupied 'front seat systemperformance' as it relates to child head injury potential (I.e. HIC) of rear seatedchildren during rear impacts. Of primary interest is: whether or not a adult occupiedfront seat will collapse into a child seated behind, and; if front to rear contact is made,under what conditions will it result in head injury to the rear child. Variables studiedincluded: non-linear seat strength; impact severity (I.e. speed change); front adultoccupant size; rear child size; and 2 vehicle types. Front seat strength levels rangedfrom about 3.1 kN, for a typical single recliner seat, on up to about 14.7 kN for acommercially available 'belt-integrated' seat design. Impact severity levels rangedfrom about 20-kph on up to 50-kph speed changes. Front adult sizes ranged from asmall female (I.e. 50 kg) on up to a larger male of about 110 kg. Rear child sizesincluded a 3 year-old, seated in the 'built-in' booster seat of a minivan, and a 6 yearold,seated in the rear bench seat of a 4 door sedan. Analysis of the 3 year-old childhead injury potential was conducted prior to the running of sled-buck validation tests.Refinements were made to the non-linear front seat computer model for the study ofthe 6 year-old. Sled-buck tests were also run for this case. The predicted and test HICcurves compared well in each case. Finally, the child HIC data was plotted over arange of variables (I.e. front occupant weight versus rear impact severity) and theresults were compared with data from actual accident cases to validate the analysis.