Study On Impact Response Of Helmet-Windshield And Head Injury

Motorcycle helmets are commonly used safety protective equipment,which can protect the head of the motorcyclist very well.It includes several main components such as foam liner,composite shell and chin strap.In the traffic accident,the head of the motorcyclist is likely to impact on the windshield of the automobile,which is likely to cause helmet damage,windshield fracture and head injury.Therefore,in this paper the finite element model of motorcycle helmet will be established to simulate the impact process between helmet and windshield and the head injury characteristics will be studied,so as to provide a scientific basis for head safety protection and helmet design.Firstly,the finite element model of the motorcycle helmet will be established,and the crushable foam model and fibers-reinforced composite shell model are used to describe the impact damage of the motorcycle helmet.The finite element model of Hybrid-II headform will be established and verified by the impact test.The verified Hybrid II head and helmet model will be assembled,and the accuracy of the helmet model will be verified with the aid of the oblique collision experiment.In addition,the effectiveness of motorcycle helmet will be verified by four ECE 22.05 impact tests.The FEM model of windshield glass will be established by the intrinsic cohesive zone method with consideration of the glass fracture and the possible debonding between glass and PVB layers.Finally,in order to study the mechanical behaviors of motorcycle helmets and head injury,the parametric study on the normal and oblique collisions will be conducted.In the normal collision,the protective performance of the helmet will be studied by comparing the mechanical response of the helmeted head and the single head impacting on the windshield.Then,the influence the impact speed,the impact attitude of the helmeted headform and the collision position of the windshield on the head response,the energy absorption of the helmet components,and the windshield fracture will be studied.In the oblique collision,the effects of the impact speed,the density of the helmet liner,the impact direction and angle of the helmet on the headform response,the energy absorption of the helmet component,and the windshield fracture will be studied as well.