Analysis of a UTV Axle Fracture Associated with Rollover

Abstract

An analysis of the fracture mechanism of a rear axle shaft of an off-road side-by-side utility vehicle (UTV) is presented in this paper. Two minors were recreating; they were riding a UTV within the fenced confines of the family farm. While driving on a dirt trail at a substantial velocity, the UTV yawed hard to the left, just before the turn in the trail. The leading side passenger’s side tires dug into the soft soil, and the UTV overturned for three-quarters of a revolution. The belted driver was partially ejected during the overturn and fatally pinned underneath the vehicle’s tubular rollover protective structure. After the event, the vehicle could not be driven as the left rear axle was fractured nearest the inner race of the outboard constant velocity (CV) joint, and the wheel hub and disc brake system were damaged. The investigation answered the question: “Did the overturn cause the axle fracture, or did the axle fracture cause a braking action and initiate the overturn?”