Real car versus driving simulator comparison of head dynamics in emergency braking events

This paper presents a pilot study which aims at comparing the results of dynamic ranges of motion made in real conditions versus virtual conditions. Whiplash remains a big socio-economic issue and the need to implement virtual reality to better understand the head stabilization strategies is here spelled out. To do so, we proposed two experiments in which subjects are seated on the front passenger seat and are subject to a given deceleration. The vehicle accelerates to a given speed, maintain its speed for a short time then proceed to the braking event which is either a custom one or the natively equipped emergency automated braking system. Range of motion and acceleration of the head are recorded. The final goal of the study is to replicate the experiment on a hexapod driving simulator. We expect the results of this replication to legitimate the comparison between results from real tests and results obtained using driving simulators. Doing such tests should reduce their human and technical costs and give a better knowledge of the participant cognition by the perfect control of the visual environment.PHC FASIC, Fondation Arts et Métier

Head dynamics during emergency braking events

The on-going automation of our vehicles will take away the driver’s attention from the road and the driving task. This results in the car occupants’ paying less attention to the exterior environement of the vehicle and also to an increased prevalance of Out-Of-Position (OOP) seating arrangements. However, emergency braking events are still likely to happen and one can wonder about the effectiveness of restraint systems which are designed for in-position occupants, as reported by Subit et al. (Subit et al., 2017). This study aims to investigate the influence of several seating positions on the head kinematics of car occupants during various braking and speed conditions.PHC FASIC PhD travel grant Fondation Arts et Métiers through the Réseau Sant

A biomechanical model of traumatic contusional injury produced by controlled cerebrocortical indentation in sheep

International audienceA biomechanical model of traumatic contusional injury was used to map axonal damage and neuronal reaction proximal and distal from the contusion. The model uses a precisely controlled and characterised dynamic indentation of the cerebral cortex of anaesthetised sheep. The indentation (16.15-16.50 mm deep; contact speed 1.2-1.24 m/s) is made through a 20 mm craniotomy in the frontal bone. The brain is then perfused-fixed after 6 hours and sectioned at 5 mm intervals. Immunohistochemistry was used to detect axonal injury and neuronal reaction. Quantitation of injury was by an automatic counting algorithm applied to micrographs of each entire section. These maps were cross-checked with manual counts. The injury was characterised by well-defined zones radiating from the impact point; these were a region of haemorrhagic and necrotic tissue, subadjacent penumbra of axonal injury, and distal multi-focal and diffuse areas of neuronal positivity. The model includes precise characterisation of the contact load and the pattern of injury. This will allow future finite element modelling to be used to explore quantitative relationships between several forms of neural damage and the dynamics of the tissue deformation in a finite element model of the insult