Automobile Wheel Lug Nuts
Accident
A Ford automobile was taken to a garage for a brake pad change. When the rear wheel was replaced, the lug nuts which hold the wheel in place
had been
improperly tightened. After one month of driving, the wheel came loose from the automobile and a one vehicle accident and personal injury resulted.
 .
Photograph A: Overall
view of wheel which separated from the axle in a one vehicle accident.
Metallurgical failure analysis revealed that two of the five wheel lugs failed by metal fatigue. The lug nuts from the three remaining wheel lugs totally "backed off" allowing
separation of the wheel from the automobile.
Photograph B: Close-up view of axle plate and wheel
studs. Note three of five wheel studs are present.
Two wheel studs failed by metal fatigue. The two
wheel studs that failed by metal fatigue are denoted
with white arrows.
The
automobile wheel rim lug holes were completely "wallowed" out of round during the one month driving time.
Photograph C: Close-up view of wallowed out wheel
stud hole in wheel rim.
The automobile accident occurred as a result of the rear wheel lug
nuts being improperly tightened, allowing the rear
wheel and tire to come loose from the subject
automobile.
Back to top
|
Dr.
R. Craig Jerner, Ph.D., PE specializes in accident
investigation and metallurgical failure analysis,
with over 30 years experience as a metallurgical
consultant and accident investigator. He has
testified as a metallurgical expert in over 250
depositions and more than 70 court appearances. If you or someone you know should need the services of Dr. Jerner and J.E.I. Metallurgical, please visit our web site at the buttons below, or e-mail Dr. Jerner --- 