Research On Injury Protection Of Children's Occupants Based On Multi-angle Collision Of Vehicle Side

The urban traffic roads in China are mainly in the form of plane intersections,and the number of side collision accidents accounts for 41.81% of the total accidents.The death rate of children's occupants under side collision conditions is the highest among all Collision conditions.The current global regulatory standards mainly evaluate the risk of child injury under the side 90° collision conditions.The domestic and international research also focuses on the side 90° collision conditions,and there are few studies on the other side angle collisions.However,the actual traffic accidents indicate that the side angle impact collision also accounts for a large proportion,and the child occupants in the side angle angle collision condition have different kinematic responses under the 90° collision condition.In order to further study the safety of children's occupants under side collision conditions,based on the statistical data of traffic accidents,it is of great significance to carry out research on the damage of children's occupants in the side multi-angle collision conditions.In this paper,two different types of child restraint systems(CRS)are selected,namely three-point seat belt type CRS A and ISOFIX type CRS B.According to traffic accident statistics,three side collision angles of 30°,60° and 90° are selected.The Q series 3 year old dummy model was used,and the vehicle side impact finite element model was established based on 2018C-NCAP.The kinematic response and injury risk of the 3-year-old child occupant under different angles of side impact were analyzed,and the child restraint system was optimized and improved according to the analysis results.The simulation results show that the larger the collision angle,the greater the intrusion,intrusion speed and intrusion acceleration of the door.In the 90° working condition,the impact is relatively large.Even if the dummy's head is within the CRS protection range,the impact with the headrest will still cause a large head acceleration and a large risk of injury.However,under the impact angle(30° and 60°),the speed of the vehicle by the collision is large,so the forward displacement of the Q3 dummy is large,and the five-point seat belt is easier to slide off the shoulder of the dummy,The head easily exceeds the CRS headrest protection range.The peak value of the Resultant acceleration of the child's chest increases as the angle of collision increases.Cause of the child's dummy is always within the CRS protection range.The greater the collision angle,the impact on the chest of a child's dummy is greater.The addition of the chest clip prevents the five-point belt strap from slipping off the shoulder,which has a certain effect on restraining the child's dummy,but there is a phenomenon of "stretching the neck",thereby applying a shearing force to the lower neck of the child's dummy.In turn,the upper neck force is increased.The improvement of the shape of the headrest based on the addition of the chest clip can further enhance the protection of the head and neck of many children's dummy,but the head of the child dummy still exceeds the protection range of the CRS A headrest.Strengthening the rigidity of the headrest and the stiffness of the headrest and the back of the seat facilitates further restraining the head of the child's dummy.The five-point seat belt preload has a certain effect on restraining the head movement of the child dummy.The addition of the side anti-collision block can improve the deformation of the middle part of the child safety seat flanks,and achieve the effect of reducing the synthetic acceleration of the child occupant's chest.The anti-collision block stiffness has a certain influence on the risk of child dummy injury.