APPLICATION OF A SIMPLIFIED LOWER LEG MODEL TOIMPROVE INSTRUMENT PANEL RESPONSES IN KNEEIMPACT FRONTAL CRASH TEST

摘要

The European Car Assessment Programme (EuroNcap) was created in 1996 with theaim of providing customers a fair, meaningful and objective information of the impactperformance of cars. Through that, EuroNcap aims to encourage manufacturers toexceed the minimum statutory standards established by law and to bring passivesecurity improvements throughout the European Union. The tests used are based onthose developed for legislation by the European Enhanced Vehicle safety Committee(EEVC), for frontal and side impact protection of car occupants, which may becomepart of the type-approval requirements for passenger cars sold in the European Union.Current efforts related to obtaining the maximum qualification on Passive Safetybehaviour are of mayor concern in the development phases of a new automotivevehicle. In that sense, EuroNcap Assessment Programme constitutes the standardmeasure to evaluate dummy responses in Frontal crash tests, where differentmodifiers to the assessment criteria and limit values are applied and can dramaticallyreduce the global qualification.Modifiers related to Knee, Femur and Pelvis (Variable Contact location &Concentrated Loading) are very influenced by the design of the Instrument Panel (IP).Up to now, huge engineering tasks are carried out with the purpose of improving itsresponse in frontal crash, in the late development stages where the IP is fullyintegrated in the vehicle, and is not suitable to be extremely redefined.In order to prevent these problems and to provide an efficient tool to account for thesephenomena from the early design stages, a reduced CAE simulating tool has beenproposed and developed. This consists of a simplified lower leg finite element model,based on the Hybrid III dummy, that integrates all the members and sensors formeasuring Femur compression, Knee slider compressive displacement, Tibia Indexand Tibia Compression, which are the current parameters related to injuries measuredin EuroNcap frontal crash tests.The use of this CAE tool and its state-of-the-art associated methodology aredemonstrated in the engineering development phases of IP, making use of the derivedconclusions in the re-design activities when impacting the lower leg model proposedto first dashboard prototypes.