MADYMO MODELING METHOD OF ROLLOVER EVENT AND OCCUPANT BEHAVIOR IN EACH ROLLOVER INITIATION TYPE. IN: OCCUPANT AND VEHICLE RESPONSES IN ROLLOVERS

This chapter, from a comprehensive text on vehicle and occupant responses in rollovers, considers the MADYMO modeling method of rollover event and occupant behavior. The authors focuses on occupant kinematics in the initial phase of the rollover; this is critical in determining the restraint system activation timing. The authors report on a study that included six rollover tests consisting of six initiation types: FMVSS 208, SAE J857, corkscrew, curb trip, soil trip, and ditch rollover. From this test data, MADYMO models were constructed of the vehicle and occupant. The test data included the influence of gravity, therefore the authors developed a method to adjust for the influence of gravity in the MADYMO models. Results showed that in the trip-over tests (curb and soil) there is a tendency for the near-side dummy head to move toward the roll direction before a significant roll angle was developed (due to the vehicle's lateral acceleration). The occupant behavior in SAE J857 and Ditch tests is slower than the curb trip or soil trip test. In the corkscrew test, the occupants initially move away from the roll direction of the vehicle; once the vertical force from the ramp is removed, the dummies move toward the outside of the vehicle.