Sensitivity Study of Jordan Rollover System and Unconstrained Model

Abstract

Finite element analysis was used to compare the dynamic rollover performance of a midsized sport utility vehicle with a strengthened roof in a Jordan Rollover System (JRS) test with an unconstrained rollover under the same initial conditions. The JRS can control closely the initial conditions of a vehicle being subjected to a rollover test. This research was proposed to study the ability of the JRS to emulate the vehicle kinematics and roof crush resulting from an actual rollover. An additional sensitivity study for the test bed mass and yaw angle was performed. The model was given initial conditions at impact similar to the JRS common values. These conditions were a roll angle of 145°, a pitch angle of 5°, a yaw angle of 10°, a test bed speed of 24 km/h, a vertical drop height of 10 cm, and a roll velocity of 190°/s. The finite element model of a 2003 Ford Explorer was used in this study and was validated against several full-scale tests. Then the roof was strengthened to meet the new federal roof regulation. Computer simulations comparing a JRS test with an unconstrained rollover showed that during a pure roof crush phase, both models behaved similarly. Afterward, some variations occurred, but the differences were less than 5%. For different test bed mass, the only significant difference between the model results was the final test bed speed. Finally, increasing the yaw angle in a JRS test showed a decrease in roll rate and intrusion characteristics of less than 5%.