Numerical approach to assess critical installation of vehicle restraint systems
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In the last few years road passive safety has become an evolving field due to the increase of mobility and consequently of the increase of traffic. Road authorities are deeply involved in this process in order to reduce the risks and consequences of accidents, such as off-roads and heads-on collisions, improving vehicle restraint systems and other safety features. The use of virtual testing can represent the key tool to make the field evolve faster and in a cost-effective way. In this view, virtual testing can be used to speed up test procedures or reduce the number of numerical tests and also to study different and more complicated issues related to vehicle restraint system (VRS) use and installation. The first issue consists of making reliable and robust numerical tests compared to the full scale test behaviour. This can be reached only defining common and widely accepted norms covering all aspects of crash test simulation against VRSs such as the European Technical Report 16303. This document covers almost any aspect of virtual testing starting from the modelling technique to the vehicle and test item modelling and verification and finally the validation procedure of the virtual test against a VRS. The first part of this work of thesis focuses on the vehicle modelling and verification that represent a key element of virtual testing, often underestimated. The validation procedure, according to TR 16303, is run for a coach model (13 ton) and for a passenger car (1500 kg) of different categories from the one used as a reference in the Validation Roadmap. The tests have been performed and have raised observations concerning the way these tests can be carried out in order to make them suitable for any other vehicle models. Finally a reduced version of the validation procedure has been proposed in order to make the procedure more cost-effective. The second part of this work presents the study of selected critical installation of vehicle restraint systems using the foregoing validated models. The results of these tests will be used as a reference for further installation and to enhance National guidelines. All numerical tests are performed with the Finite Element code implemented in the software Ls-Dyna.
Masteroppgave - Politecnico di Milano. Facoltà di Ingegneria Industriale. Corso di laurea in Ingegneria Aeronautica. Dipartimento di Scienze e Tecnologie Aerospaziali.