Research On The Injury Risk And Protection Of 6-year-old Child Occupant In Frontal Offset Impact

With the continuous increase of car ownership,the number of worldwide traffic accidents is also increasing.Road traffic accidents have become the main cause of death of children and young people aged 5-29.Frontal impact is the most common form of impacts in car accidents,and offset impact is the main form of frontal impacts.It is very significant that study the injury of child occupants in offset impact and put forward corresponding optimization suggestions for restraint system to improve the safety of child occupants.Three types of child restraint systems suitable for six-year-old child occupant are selected in this paper.They are the traditional child restraint system(CRS A),the high-backed booster child restraint system(CRS B),the backless booster child restraint system(CRS C).According to the test requirements of C-NCAP,Euro-NCAP and ?HS,vehicle crash models with 100%,40%and 25%overlap were established respectively.The differences of occupant kinematics responses between different overlap rates and different types of child restraint systems were studied using Hybrid ? 6YO model.The injury risk of head and chest is analyzed in small overlap frontal impact using THUMS 6YO model.Finally,the vehicle restraint system is optimized according to the occupant injuries.The results show that there are obvious differences in the kinematic responses of occupant in different overlap impacts.The smaller the overlap rate,the larger the movement range of occupant to the door side.In the 25%overlap impact,the head and arms of Hybrid ? 6YO occupant hit the door and the internal structure nearby.Damage parameters of head and neck are larger.The kinematics response of occupant constrained by different types of restraint system is also different.CRS A,CRS B and CRS C have good restraint behavior on Hybrid ? 6YO occupant.Among them,the protective performance of the high-backed booster is better than that of the backless booster.During the impact process,the occupant is within the children restraint system,and the head injury value is larger.When using THUMS 6YO human body finite element model to study occupant's head and chest injury risk in small offset impact,due to the difference of structure and material between THUMS model and Hybrid III model,THUMS 6YO head and car interior structure have a slight impact or no impact,and the injury risk of head is low,but the risk of rib fracture,heart and lung contusions is high.THUMS 6YO occupant constrained by CRS C appears submarining phenomenon during impact.The optimization results of vehicle restraint system show that the seat belt with load limiter can effectively reduce the risk of rib fracture,heart and lung contusion,increase the injury risk of brain,but the value does not exceed the tolerance limit;the inflatable seat belt can reduce the injury risk of head,ribs,heart and lung although the effect is not obvious.