An experimental study was conducted to simulate the airborne phase of a rollover. The study goals were: (1) to quantify the effect of restraint anchor locations and belt component designs in reducing head excursion; and (2) to better correlate the response between humans and an Anthropomorphic Test Device (ATD) during the high angular roll rate of the airborne phase of a rollover. A Head Excursion Test Device was designed to rotate a restrained occupant about an axis. A total of 80 excursion tests were conducted: 51 tests with a Hybrid III 50th percentile male ATD (20 static and 31 dynamic); 18 tests with a cadaver (7 static and 11 dynamic); and 11 static tests with two male volunteers. In tests using a two-point lap belt, belt angle was more significant than overall belt length in reducing head excursion. Vertical head excursion was minimized with a steep lap belt angle and short webbing length. Tests utilizing a three-point lap and torso restraint demonstrated that the torso belt reduced vertical head excursion primarily by restricting forward torso rotation. Increasing the belt webbing pretension load reduced vertical and lateral head excursion. Comparison of results from human volunteers, cadaveric and Hybrid III ATD subjects in static tests indicated that the Hybrid III ATD had the least vertical excursion. Dynamically, the Hybrid III ATD had less vertical and lateral excursion than the cadaver. (A)
Abstract