A Numerical Model to Assess the Risk of Fall in Public Transportation - Application to the Influence of the Jerk in Emergency Braking

2015 IRCOBI Conference, LYON, FRANCE, 09-/11/2015 - 11/11/2015Non-crash events (e.g. emergency brakings) are a prevalent cause of injuries for public transportation (PT) passengers. In particular, fall of standing passengers induced by the vehicle dynamics can have dramatic consequences, notably for fragile passengers, such as the elderly. One solution to mitigate this risk is to limit the aggressiveness of the interior design, which goes through the evaluation of the injury risks induced by secondary collisions. Another solution is to limit the occurrences of unbalance by identifying, and possibly adjusting, the sources of loss of balance in the vehicle's dynamics. Perturbations characteristics that induce a fall or a loss of balance have been assessed experimentally. However, the perturbations considered are extremely rarely relevant to those encountered in PT. In addition, apart from, no quantitative information exists on critical parameters, such as the Jerk of the emergency profiles. Finally, experimental results are very specific and difficult to generalise. There is, therefore, a need for a numerical tool that can evaluate the risk of fall of standing persons submitted to transient perturbations representative of PT. One of the difficulties is that, contrary to the passive human models classically used in injury biomechanics, it must include the reactions of passengers trying to restore their balance. To our best knowledge, such a tool does not yet exist. This study aims to fill this gap. It proposes a first evaluation of the model's performance and uses it to evaluate the influence of an emergency braking's Jerk on the risk of fall