ABSTRACT
Objective To propose an airbag-type helmet cushioning lining structure and analyze its protective effect on head injury of two-wheeled bicycle riders. Methods The airbag lining was applied to two typical two-wheeled bicycle helmets for bicycles (half helmets) and motorcycles (full helmets). Then kinematic and biomechanical responses of the human head model were predicted from impact simulations under test conditions of the standard GB 24429-2009 and the regulations ECE R22.05, and conventional expanded polystyrene (EPS) helmets were compared from the perspective of skull fracture and brain injury risk, so as to make comprehensive evaluation on protective performance of the airbag helmet. Results When the airbag pressure was 0.06 MPa, the relevant amount of human skull fracture under protection of airbag helmet (half/full helmet) was smaller than 120 g and 150 g, respectively; the risk of skull fracture was basically lower than 40%; the maximum principal strains of the brain were both smaller than 0.3, which indicated that the risk of mild brain injury was lower than 25%. Generally, the risk of human skull fracture and head injury under protection of airbag helmets was lower than that under protection of EPS helmets. Conclusions The airbag helmet designed in this study has a good protective effect, which can give attention to the protection of both skull fracture and head injury, providing a basic example for the design of novel helmet. Injury risk analysis can also provide the preliminary reference for emergency diagnosis on head injury of cyclists.