Abstract
Deformable structure on impacts in nowadays vehicles is a basic component of passive car safety, along with occupant retention systems.
In studying the influence of car remanent deformations on occupant injury the NHTSA (National Highway Traffic Safety Administration) database was used, out of which a series of collision tests were selected and their results were processed and interpreted.
Impact severity has been evaluated based on the following parameters: vehicle velocity change in collisions (Δv), ridedown efficiency (μ) and relative kinetic energy factor (Ec). In assessing occupant injury risk in front impacts the following injury criteria have been used: occupant thorax maximum linear acceleration sustained for 3 ms or longer (a(3ms)) and chest severity index (CSI). The correlation between Δv and the mean vehicle crush rate is not evident considering the total number of analyzed cases. Collision energy efficiency is directly proportional to mean crush and relative kinetic energy factor is inversely proportional to the mean crush in all the analyzed cases. According to the occupant protecting system (safety belt or airbag) differences were recorded between the passive safety parameters μ and Ec, respectively.
The statistical analysis reveals that injury risk is inversely proportional to the mean crush. Furthermore, injury risk assessed by a(3ms) and CSI criteria was analyzed considering the occupant safety system. Keywords: ridedown energy density, relative kinetic energy, injury risk