Occupant pre-crash kinematics in rotated seat arrangements

The introduction of automated L5 driving technologies will revolutionise the design of vehicle interiors and seating configurations, improving occupant comfort and experience. It is foreseen that pre-crash emergency braking and swerving manoeuvres will affect occupant posture, which could lead to an interaction with a deploying airbag. This research addresses the urgent safety need of defining the occupant’s kinematics envelope during that pre-crash phase, considering rotated seat arrangements and different seatbelt configurations. The research used two different sets of volunteer tests experiencing L5 vehicle manoeuvres, based in the first instance on 22 50th percentile fit males wearing a lap-belt (OM4IS), while the other dataset is based on 87 volunteers with a BMI range of 19 to 67 kg/m2 wearing a 3-point belt (UMTRI). Unique biomechanics kinematics corridors were then defined, as a function of belt configuration and vehicle manoeuvre, to calibrate an Active Human Model (AHM) using a multi-objective optimisation coupled with a Correlation and Analysis (CORA) rating. The research improved the AHM omnidirectional kinematics response over current state of the art in a generic lap-belted environment. The AHM was then tested in a rotated seating arrangement under extreme braking, highlighting that maximum lateral and frontal motions are comparable, independent of the belt system, while the asymmetry of the 3-point belt increased the occupant’s motion towards the seatbelt buckle. It was observed that the frontal occupant kinematics decrease by 200 mm compared to a lap-belted configuration. This improved omnidirectional AHM is the first step towards designing safer future L5 vehicle interiors.

Forensic Engineering Analysis of Upper Extremity Nerve Entrapment Injury Mechanisms as Related to Rear-End Collisions

Nerve entrapments of the median nerve, i.e., carpal tunnel syndrome (CTS) and the ulnar nerve, i.e., cu-bital syndrome (CT) are relatively common, reflecting traumatic and atraumatic mechanisms. Claims of such injuries in relation to rear-end collisions (particularly low-velocity or < 10 mph collisions) are often contested by the defense, acknowledging that there is no obvious relationship between the collision and the claimed inju-ries. Of the collision types (frontal, side, rear-end), it is the least clear how a rear-end collision can establish mechanisms for such injuries. Direct blunt trauma to the carpal tunnel region or the cubital tunnel region are unlikely in a rear-end collision. Also, “stretch” injuries due to hypermotion of either the wrist or elbow are unlikely, reflecting occupant kinematics, vehicle interior geometry, and other factors. A case study involving CTS and CT claims as a result of a low-velocity rear-end collision will be presented.