The influence of seatback reclination on body kinematics during low-speed frontal impact

Abstract

Safety tests are generally performed in accordance with strict procedures that involve the use of a carefully positioned dummy. Safety tests are rarely conducted with the occupant being in a non-standard position. In real life driving, occupants, especially passengers, choose a more comfortable reclined position, and in such a case the body dynamics are different from those investigated in the standard safety test. Furthermore, with the rapid development of autonomous vehicles, which provide the possibility of the position of occupants being unrestricted, the investigation of “out of position” body kinetics is becoming more important. The presented study aimed to evaluate body dynamics with various seatback reclinations. Body dynamics were verified by simulating frontal impact on a sled system with the use of a standard 50 percentile Hybrid III dummy. Points of interest located on the dummies head, neck, pelvis, and legs were traced, which allowed its trajectory to be evaluated. Additionally, the maximal extrusion and the time of motion were evaluated. It was found that the maximal extrusion in the longitude direction is the same for semi and fully reclined seats. Furthermore, a reclined seat causes head rotation, which can result in neck injuries.

The Effect of Changing the Angle of the Passenger Car Seat Backrest on the Head Trajectories of the 50th Percentile Male Dummy

“…Furthermore, it should be noted that lumbar spine injuries are well-researched in the literature, but there are few studies focusing on body dynamics in a reclined position. The diversity of seat belt reactions and altered body dynamics can negatively affect the effectiveness of airbags, especially when dealing with submersion, which increases the risk of head injuries due to the greater distance from the airbag [ 47 , 48 , 49 ].…”

“…The diversity of seat belt reactions and altered body dynamics can negatively affect the effectiveness of airbags, especially when dealing with submersion, which increases the risk of head injuries due to the greater distance from the airbag [47][48][49].…”