Development of Improved Injury Criteria for the Children

Each year, 700 children are killed on European roads and 80,000 are injured. It represents an unacceptably high burden on Europe`s society and economy. The fact that such poor results are observed, despite normal use of CRS (Child Restraint Systems) complying with the ECE 44 Regulation, underlines the high social importance of continued child safety research. The European Commission (EC) as well as National Highway Traffic Safety Administration`s (NHTSA) plan for upgrading the existing directives and legislation for frontal and side crash protection safety including additional requirements that will specify performance limits to minimize the risks from injuries to small sized occupants and children in both normal and out-of-position seating locations. These new crash specifications will require the use of additional dummies of various sizes as well as improved injury criteria that will appropriately represent injury thresholds of these population segments. Plan for upgrading existing legislation based on new improved consumer tests and results from these tests that are available for public and publish by various organizations all over the world. Existing Injury Criteria are developed on extensive analysis, for limited size dummy (e.g., an adult like dummy). By using different techniques, scientists try to applied and adopt existing Injury Criteria to other size dummies (e.g., a child like dummy). At the moment two techniques - statistical analysis and scaling - are used in developing appropriate Injury Criteria for different (non-standard) dummy size. As usually necessary data for Injury Criteria development can be collected only for a specific type of vehicle occupant under a given loading condition, (e.g., an adult male or female) statistical analysis is limited for some type of occupants. This is clearly evidenced by the lack of biomechanical data available for children. Under these circumstances scaling techniques and engineering judgment is the only approach to develop injury criteria for other size occupants. The type of scaling most commonly used at the moment is dimensional analysis. For mechanical systems this technique allows the unknown physical responses of a given system to be estimated from the known responses of a similar system by establishing fundamental scaling factors that are based on ratios between fundamental properties that characterize the two systems. In this project detailed acquisition of geometrical data and in addition acquisition of some inertial data over children population between age 4 and 14 will be considered to improve understanding of the influence of these mechanical data on children body dynamic response and injury potential during impact. Dynamic response and injury potential will be studied by using new scaling methods, based on sensitivity analysis and measured data applied to available numerical models of child body and selected existing Injury Criteria. We hypothesize that new scaling techniques will provide more complex and realistic insight how different mechanical parameters variation influence the dynamic response and Injury Criteria and therefore make scaling more realistic. We also hypothesize new scaling method based on sensitivity analysis along with measured data will make possible to considerably improve biomechanical properties of children numerical model and also improve the use of existing Injury Criteria when addressing children injury potential. Improved children numerical model and improved use of Injury Criteria will represent an important tool for evaluating vehicle safety equipment in the future.