The passive safety performance of a child seat is modulated by the design
features of the child seat and the vehicle interior. For example, in the
rear-facing configuration, the child seat impacting front structures increases
the head injury risk during a frontal crash. Therefore, this study evaluates the
effectiveness of the load leg countermeasure in improving the child seat's
overall kinematics and its capability to prevent the secondary impact on the
vehicle interior structure in a severe frontal crash scenario. An in-depth,
real-world crash investigation involving a properly installed rear-facing child
seat impacting the center console was selected for the study where the infant
sustained a severe brain injury. In addition, this crash is employed to choose
the crash parameters for evaluating the effectiveness of the load leg
countermeasure in a similar scenario.
Finally, crash sled tests are conducted using the crash signature of the vehicle
as obtained from the NHTSA NCAP rigid barrier test that matched the severity of
the actual crash. With and without load-leg conditions are compared.
The overall kinematics improved with the load leg and prevented the blunt impact
between the child seat and the front console and seats. As a result, the Head
Injury Criteria were measured below the published IARV compared to the scenario
with no load leg. Furthermore, the head injury criteria without the load leg
were 123 % higher.
The load leg countermeasure provides an additional load path that improves the
overall performance of the rear-facing child seat by keeping it more stable
during the crash. Furthermore, the vehicle floor structure provided the required
reaction load without damaging or buckling the vehicle floor. This study is
limited to the frontal crash scenario without any significant obliquity of the
impact.