Selective Sensitivity Study of the Jordan Rollover System – Comparison with the Un-Constrained Model for Different Test Bed Mass and Yaw Angle

In this paper, finite element analysis was used to compare the dynamic rollover performance of a midsized SUV with a strengthened roof in a Jordan Rollover System (JRS) test with an Un-Constrained (UC) rollover under the same initial conditions. The JRS has the ability to closely control 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: roll angle of 145°; pitch angle of 5°; yaw angle of 10°; test bed speed of 24 km/h; vertical drop height of 10 cm; and roll velocity of 190°/s. The finite element model of a 2003 Ford Explorer was used in this study and was validated towards several full-scale tests. The roof was then strengthened to meet new federal roof regulations. Computer simulations comparing a JRS test with an Un-Constrained rollover showed that during the pure roof crush phase, both models behave similarly. Afterwards, some variations occur but the differences are 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 on a JRS test showed a decrease in the roll rate and intrusion characteristics of less than 5%. Working Paper NCAC 2011-W-006 October 2011