Forensic Engineering Analysis Of A Pickup Truck Wheel-Off Failure

Abstract

While Traveling On An Interstate Highway, A Pick-Up Truck Went Out Of Control As A Result Of The Detachment Of Its Left Rear Wheel. The Loss Of A Wheel From A Moving Vehicle Obviously Represents A Significant Safety Hazard, And, Apparently, Is Not A Rare Occurrence. Wheel Detachment From A Moving Vehicle Causes Instability Of The Vehicle, Which Can Lead To A Series Of Catastrophic Events, Resulting In Serious Injury Or Death. The National Transportation Safety Board Estimates That Approximately 750 - 1050 Reported Accidents And 40-50 Fatalities A Year Occur Due To Truck-Wheel Separations The Wheel-Off Failure Discussed Herein Resulted From The Loss Of Adequate Clamping Load On The Nut/Lug/Wheel Joint. A Case Study Is Presented Of A Vehicle Wheel-Off Failure, After More Than 2000 Miles Of Travel, Resulting From Inadequately Torqued Lug Nuts. An Analysis Is Presented To Determine The Elements Of Causation.