Abstract
Keywords
Knee, frontal crash, instrument panel, passive safety, simulation
Abstract
The European Car Assessment Programme (EuroNcap) was created in 1996 with the aim of providing customers a fair, meaningful and objective information of the impact performance of cars. Through that, EuroNcap aims to encourage manufacturers to exceed the minimum statutory standards established by law and to bring passive security improvements throughout the European Union. The tests used are based on those developed for legislation by the European Enhanced Vehicle safety Committee (EEVC), for frontal and side impact protection of car occupants, which may become part of the type-approval requirements for passenger cars sold in the European Union.
Current efforts related to obtaining the maximum qualification on Passive Safety behaviour are of mayor concern in the development phases of a new automotive vehicle. In that sense, EuroNcap Assessment Programme constitutes the standard measure to evaluate dummy responses in Frontal crash tests, where different modifiers to the assessment criteria and limit values are applied and can dramatically reduce 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 its response in frontal crash, in the late development stages where the IP is fully integrated 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 these phenomena from the early design stages, a reduced CAE simulating tool has been proposed 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 for measuring Femur compression, Knee slider compressive displacement, Tibia Index and Tibia Compression, which are the current parameters related to injuries measured in EuroNcap frontal crash tests.
The use of this CAE tool and its state-of-the-art associated methodology are demonstrated in the engineering development phases of IP, making use of the derived conclusions in the re-design activities when impacting the lower leg model proposed to first dashboard prototypes.