Research Papers

Pre-Rollover Vehicle Dynamics of SUV's in Untripped Rollover Tests

Filename Gilbert.pdf
Filesize 712 KB
Version 1
Date added June 6, 2010
Downloaded 2 times/fois
Category 2010 CMRSC XX Niagara
Tags Session 3C
Author/Auteur Micky Gilbert, Brad Stolz

Abstract

The relationship between vehicle motion and scene evidence is of critical importance when reconstructing an untripped vehicle rollover accident. The events occurring prior to an untripped rollover frequently include a rotation of the vehicle about the vertical axis (yaw), leaving behind very distinct roadway markings. Such scene evidence (primarily tire and wheel markings on the roadway surface) aids in the reconstruction of the vehicle’s pre-rollover path. Given the pre- rollover yaw marks, the vehicle’s track width and the vehicle’s wheelbase, the sequencing of the pre-rollover dynamics can be determined, including vehicle yaw, vehicle path and slip angle. Since an investigator is rarely present at the scene during the actual rollover event, they must be able to view the scene evidence and extract from it these parameters that describe the vehicle motion path prior to the rollover event. This paper will present data from instrumented rollover testing of an SUV with very low rollover resistance with the intent of establishing a correlation between the roadway markings and the occurrence of yaw-specific vehicle motion, and will then discuss methods of correlating this motion back to the roadway markings. Relationships will be established between vehicle motion (such as the onset of vehicle yaw, the point of maximum lateral acceleration, the point of vehicle two-wheel-lift, and the effective deceleration during the pre-rollover motion) and yaw-specific roadway evidence (such as tire mark “separation” and other markings). The process of evaluating such roadway evidence and interpreting the overall vehicle yaw movement will be discussed in detail. Such relationships will become important to the investigator of any vehicle yaw, including those that lead up to an untripped rollover. The evidence can also be compared to that from tripped rollover events, which involve different dynamics.

Micky Gilbert and Brad Stolz