Injury Biomechanics in Railway Backrest Table Design

The study presented here concerns a parametric study for the analysis of the influence of backrest table design during crashes of railway vehicles, focusing on the protection of occupants of railway coach interiors. A railway accident is described by the primary collision, in which the vehicle is subjected to an abrupt deceleration causing the unrestrained occupants to continue the original motion. Then the occupants are projected through the vehicle until the secondary collision occurs with their contact with some part of the interior of the vehicle or with other occupants. The strategy presented here combines and explores the already developed railway structures for crashworthiness with injury biomechanics. The methodology attends the railway accidents specificities such as the inexistence of restraints and the larger distance between contact features, which decreases the predictability on the kinematics of the occupants. Due to the importance of the vehicle interior features for the potential injury of the occupants during the secondary collision, in particular the seating layout with backrest table for which the experimental sled tests were not performed due to its cost, a parametric study was conducted with a numerical model of a reference simulation scenario characterized by the seating pitch of the first class coach. Simulation results suggest design modifications that are discussed in the scope of the reduction of the biomechanical injury indices for the occupants.