The Numerical Investigation Of Head Injury In The Dummy-windshield Impact Process

Head injury is one of the most frequent and severe injuries in traffic accidents,which can lead to permanent disability or death in severe cases.The outside unprotected road users,such as pedestrians,motorcyclists and skateboarders,have a high probability of having their heads in contact with the windshield,so the buffering and energy absorption characteristics of windshield have a great effect on head injury.Therefore,this thesis will establish pedestrian-car and skateboarder-car collision simulation models to study the head injury of pedestrians and skateboarders and the impact response of the windshield,so as to provide a theoretical basis for the passive safety of vehicle.Firstly,the material constitutive models of Hybrid-Ⅲ dummy model are studied,then,they are transformed into corresponding material constitutive models of ABAQUS software.On this basis,pedestrian and vehicle FE models based on ABAQUS software are established.Then,the process of pedestrian-vehicle collision is simulated.The effectiveness of the established pedestrian and vehicle finite element models are verified by comparing the acceleration curve of tibia and kinematics behaviour of pedestrian from ABAQUS with literature results.In order to consider the fracture between glass layers and the debonding between glass layers and PVB layer when the head impact with windshield,the intrinsic cohesive model method is used to establish the windshield model.The proposed approach is verified by comparing linear acceleration of pedestrian head from the simulation with the literature results.Then,in order to study the effects of vehicle speed,pedestrian standing angle,pedestrian standing position and pedestrian gait on pedestrian’s kinematics behaviour,head injury and impact response of windshield when collision,the parametric study on pedestrian-vehicle collisions are conducted by using the pedestrian and vehicle models.The results indicate that the higher the speed of the vehicle,the larger the angle between the pedestrian’s body and the direction of the car’s movement,and the closer the pedestrian’s standing position is to the end of the car’s front anti-collision beam,the more severe the pedestrian’s head injury will be.When the pedestrian standing on the right foot（impact side leg standing）and left foot front and right foot back（impact side leg back）,the body rotation range is larger,and the head injury is more serious.Finally,a skateboarder-vehicle collision model is established and a parameterized study is carried out to analyze the effects of sliding speed,sliding posture,squatting height and sliding angle on skateboarder’s kinematics behaviour,head injury and impact response of windshield when collides with vehicle.The results show that when skateboarder and vehicle move towards each other,the skateboarder’s head injury is more severe.The sliding posture has a great effect on the kinematics behaviour and head injury of the skateboarder,and the head injury is the most severe when standing cross.When squatting,the skateboarder’s body will yaw during collision process,which cause higher HIC value compared with the straddling posture,but the RIC value will decrease.The larger the angle between the skateboarder’s sliding direction and the moving direction of the car,the greater the head HIC value.