Calculation of new head injury criteria through a Simulink model and an evaluation of the DAMAGE’s rotational contributions

In car accidents, head injuries are among the main causes of death or disabling condition, involving high costs both in terms of human lives and costs for the national health system. Specific injury criteria used to analyze such injuries, such as BrIC and DAMAGE, are therefore essential in order to make cars intrinsically safer for occupants. The thesis work that I set out to do focuses precisely on these two criteria: specifically, it consists in the creation of an alternative calculation model to the one used by the ITALDESIGN team, carrying out afterwards experimental applications. Chapter I provides a general overview of automotive safety through: 1. an historical introduction about car safety and its development; 2. the crash tests setups in the European (Euro NCAP) and American (NHTSA) protocols; 3. the evolution of the Crash Test dummies used; 4. the current injury criteria evaluated for the various body compartments. Chapter II, on the other hand, focuses on the in-depth analysis of those topics that are closely related to the procedure adopted by the experts for the calculation of these two criteria. To begin with, the study of oblique impact in Europe and the USA is dealt, continuing with a description of the THOR which is currently the dummy of choice in the testing phase; to conclude, a detailed discussion is made, both for the BrIC and the DAMAGE, about their development and application. Chapter III specifically includes the aim of the proposed work: the computation through the Matlab-Simulink calculation software of the BrIC and DAMAGE injury criteria, after modeling the head-brain system, which can be traced back to a second-order system, constructed using a physical mass-spring-damper analogue. The simulations results are then compared with those obtained by the company and the differences between them are discussed.