Head Neck Injury in Autonomous Driving, Experiments and Simulations to see the Influence of Rotated Head Positions

Car accidents are frequently the cause of neck injuries ; these in juries are painful, expensive for society and challenging to simulate. Until now, the injury criteria are computed based on acceleration data of the test dummy used in the safety crash tests, both for pedestrian safety tests and interior pas senger safety. Human body models (HBM) can be used to move this assessment procedure toward soft tissues related injury criteria. For these reasons, the main scope of this work is to try to explain how injury in the neck occurs based on stress and strain analysis of the soft tissues present in the neck employing nite element models. The automotive safety assessment could be done in the future using simulations with HBM and soft tissue injury criteria. In the literature, there is a signi cant di erence between male and female injury occurrence and the probability of obtaining tissue damage due to rear-end collisions. Women are more likely to undergo whiplash associated disorder (WAD) injuries, and this is the reason why the model used in this work is representative of a 50 percentile female head and neck. The main contribution of this work is to assess injury metrics for soft tissues such as ligaments, intervertebral discs (IVD), facet joints and vertebrae corti cal bone endplate within rear-end collision scenarios. The scaling of the input pulses gives a second contribution to see the di erences in the neck behaviour at higher impact acceleration levels. A third contribution is provided by the assessment of injury in multidirectional collisions. This is considered a relevant topic since, with the autonomous driving development, the ordinary passenger seating positions could be rotated in di erent ways and the risk of neck injury may increase, leading to di erent kinds of WAD mechanisms. The thesis is structured to explore the research topic comprehensively through four interconnected chapters. Chapter 2 presents a preliminary review of the literature necessary to understand the basics of WAD injuries, FE HBM, soft tissue injuries, and experimental tests that investigate WAD. Chapter 3 explains the methods used to investigate new injury criteria and how the simulations and post-processing of data are obtained systematically, ensuring transparency and replicability. In Chapter 4, the numerical ndings are presented, rstly with a comparison with previous literature studies and then showing injury criteria according to standard sled-test simulation, scaled simulations, and rotated sim ulations. Tables and gures are present to highlight key patterns and trends. Subsequently, the thesis ends with a discussion chapter that interprets the result in the context of the literature and new framework. An appendix for additional material is present at the end of the script.