The Effect of Changing Vehicle Seat Stiffness: A MADYMO Sensitivity Analysis 2020-01-0524
In low-speed, rear-end collisions, the occupant moves rearward relative to the vehicle and interacts with the seatback and seat bottom as the occupant loads the seat. Due to the interaction of the occupant with the seat, the seat stiffness can affect the kinematics of an occupant. Generic seat stiffness values are often used as input parameters in computer programs, such as MADYMO, that are used to model low-speed, rear-end collisions and simulate occupant kinematics. To create an accurate simulation, the model should take into account all aspects of the accident including the person involved, the subject vehicle, and the subject vehicle seat. Recent research has demonstrated that the stiffness of the compressible structure of the seat, comprised of foam and springs, is statistically significantly different between vehicles, and there are significant variations between different regions within a single vehicle seat. To improve the accuracy of occupant kinematics, this information can be used to better inform the model. Using seat stiffness values obtained from a variety of commercially available vehicles, a sensitivity analysis was completed in MADYMO. In addition to changing the stiffness within the seat, the seat bottom and seat back were modeled either as one component or two. The relevant outputs include head velocity, head acceleration, cervical spine loads, and lumbar spine loads. The MADYMO simulations of occupant kinematics were also compared to the occupant kinematics of anthropomorphic test dummies in sled tests simulating low-speed, rear-end accidents. This sensitivity analysis attempts to determine the effect of vehicle seat stiffness on occupant kinematics and injury mechanics.
Denise R. Cruise, Bethany L. Suderman, Nicholas H. Yang, Lenka Stepan, Irving S. Scher