Every year more than 1.3 million people die in road traffic worldwide. Pedestrians are among the most vulnerable road users, both in terms of their statistical relevance and because of the often very high severity of injuries. In addition to promoting active safety systems, legislation, consumer protection organisations and vehicle development continue to focus on the advanced optimisation of passive safety in order to further improve the protection of pedestrians and other unprotected road users. In the bonnet area, due to the reduced mass inertia, lightweight design required to improve efficiency and driving dynamics, represents a conflict of objectives with the pedestrian protection during head impact scenarios. A favourable deformation behaviour needs to be optimised for compliance with biomechanical limits during head impact while also minimising the required deformation space and is characterised by a rapid increase in force with subsequent degression. Current passive structural measures to improve pedestrian protection show specific disadvantages in this respect. Within the scope of this work, a series-capable concept for the realisation of pedestrian protection of a lightweight engine hood based on carbon fibre reinforced plastics has been developed, realised as prototypes and validated by physical testing. The developed concept of an engine hood in integral CFRP sandwich design with a compression- and shear-resistant foam core achieves a weight reduction of 57.6 % compared to the steel reference. At the same time the negative effect of the reduced mass inertia with regard to an optimised deceleration of the head can be compensated by a tailored increase of the local stiffness in combination with a high energy absorption. In addition, it is shown that the acceleration curve during head impact can be optimised by varying the foam core topography according to a theoretically optimal characteristic. In particular, the required deformation space can be reduced by increasing the local stiffness, which can be particularly advantageous in demanding package situations. In addition to demonstrating the functional and safety-relevant properties of the concept, the suitability for series-production and a-class paint quality are demonstrated as well. Compared to other solutions, the integral CFRP sandwich design thus offers a high potential for pedestrian protection and weight saving in series production.
Fußgängerschutzpotenzial von Leichtbau-Motorhauben
Pedestrian protection potential of lightweight engine hoods
2021-01-01
1 Online-Ressource pages
Dissertation, RWTH Aachen University, 2021; Aachen : RWTH Aachen University, Schriftenreihe Automobiltechnik 241/21, 1 Online-Ressource (2021). = Dissertation, RWTH Aachen University, 2021
Miscellaneous
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German
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