Analysis of the Effect of Infant Carrier’s Webbing Tension on 18-month-old Child Occupant’s Chest Accelerations in Frontal Crash Accidents Based on Experimental Validations

Abstract

Infant carriers play an important role in protecting child occupants from severe injuries caused by collisions, but the tension of harness webbing cannot be controlled properly most of the time. Infant carrier’s user manual or instruction generally contains little information about the extent to which the adjusting belt should be pulled to cause the necessary webbing tension, and it is often neglected that the infants should be restrained securely. In order to improve public awareness, it is important to ascertain the effect of infant carrier’s webbing tension on the occupant’s chest accelerations. A testing scheme including 12 dynamic tests was devised and conducted, and test conditions were controlled strictly to ensure the accuracy and objectivity of results. P1.5 dummy’s resultant and vertical chest accelerations were collected and analyzed. Both ISOFIX installation and seat belt installation methods were taken into consideration without lack of generality. Sled’s accelerations and velocities were set and acquired, which constituted the fundamental testing conditions of dynamic tests and ensured the repeatability and reliability of tests. Furthermore, dummy’s chest acceleration pulses were monitored and recorded, and the data were evaluated in accordance with criteria defined in relevant technical standards. The dummy’s chest accelerations were classified into 2 groups according to child restraint systems’ installation methods, i.e., the ISOFIX group and the seat belt group. In each group, both resultant chest acceleration and vertical chest acceleration were involved. Universal phenomena were displayed in all the tests, and the larger the tensile forces were, the lower the chest accelerations were in tests. Based on experimental validations, the relation between webbing’s tensions and chest accelerations in frontal crash accidents was verified. Furthermore, suggestions were made about adjusting the webbing tension and the proper use of infant carriers.