Helmet protective performance via reconstruction of electric two-wheeler rider's head-to-ground impact accidents

摘要

Numerous studies, including epidemiological, experimental and simulation studies, have shown that helmets can provide good protection for the two-wheeler (TW) rider's head and reduce the casualty rate due to head injuries during an accident. The objective of this current study was to evaluate the protective performance of a helmet based on in-depth accident reconstructions of electric two-wheel (ETW) rider's head-to-ground impact validated by the video information that provide clear and complete kinematics of ETW rider. Furthermore, validated finite element (FE) models of the helmet and human head were used. Three real-world accident cases (Cases A, B and C) were evaluated, in which, the riders' head were injured by ground impact after collided by the vehicles. In Case A and Case B, the helmet could effectively reduce the risk of skull fracture to 46% and 4%, respectively; whereas the risk of a skull fracture was up to 94% in Case C. In addition, the helmet can slightly reduce the risk of DAI injuries to 39% in Case C, while the risk of concussion cannot be reduced in three cases. In the violent impact condition such as in Case C, the bottoming out of the liner foam makes helmet lose effective protection against skull fracture. The connection between the shell and liner foam largely affects the helmet's protection against the brain injuries such as DAIs and concussions. The findings point out the lack of protective performance of the helmet and further provide more comprehensive guidance on the safety design of the helmet.