Modeling and evaluation of child safety seat and restraint system for aerospace application

by Patil, Ashutosh Ashok

The increasing trend of carrying babies in aircraft raises the question of their safety. The National Transportation Safety Board (NTSB) states that all occupants should be restrained during takeoff, landing, and turbulent conditions and that all infants and small children should be restrained in an approved child restraint system appropriate to their height and weight. The present child seats are primarily developed for automotive applications and not tested for aerospace applications; therefore, there is a need to test these child restraint systems for aerospace test conditions. Also, the cost of actual testing and the secrecy maintained by manufacturers make research process difficult and increase the importance of computer simulations. The need for validated computer models is imperative. The 12-month-old and 3- year-old child seats used in this research have been approved for use in automobiles but not in aircraft. This research attempts to develop and validate a child restraint seat model for aerospace application. Two types of child restraint seat models - 12-month-old and 3-year-old child seat models were developed and validated using the computational tool MADYMO. The surface models of these two types of seat were exported in IGS format and meshed using Hypermesh. The meshed model was then defined as a facet in MADYMO. These models were validated for the type II dynamic test condition specified according to FAA regulations. Validation was carried out by comparing the kinematics in the simulations and the actual sled tests. To ensure validity, a comparison of various acceleration profiles and force/moments experienced by the occupant under test conditions were compared. Furthermore, the injury levels sustained by the occupant in the actual sled tests and the simulations were compared. Thus, the seat models were validated for their practical applications. These simulated models can help in future research on child safety and to generate guidelines for child restraint use in aircraft. v