Radial Tire Tread Separations

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Radial tires offer many advantages over bias ply tires, and steel was recognized early on as having desirable properties for the construction of radial tire belts. However, mating steel structures to the rubber structures in a tire is an engineering challenge and one of the principle difficulties in making safe and durable radial tires. The steel/rubber interface is exposed in service to adverse mechanical, thermal, and chemical stresses which include combinations of static and cyclic (fatigue) stresses, as well as potential invasion of the structure by cuts and puncturing objects, moist air, and electrolytes such as sodium chloride. Deterioration of the composite structure…

Wheel Separations

In October 1991, the National Transportation Safety Board investigated a fatal accident in which a two-axle cargo van truck lost a front wheel, which rolled into the path of an oncoming school bus carrying 46 fourth-graders and their chaperones. The 365-pound wheel smashed through the bus windshield and entered the passenger compartment, killing two children and a chaperone. In the 3 weeks following this accident, two more fatal accidents involving truck-wheel separations occurred in North Carolina…

Tire Mounting Machine Defects

Concern about the design of machinery in relation to hazards presented to machine operators and others has a very long history dating from the Industrial Revolution and has progressively developed particularly since the end of the 19th century. A process for systematically achieving appropriate product safety has evolved in product design called failure mode and effect analysis (FMEA). This requires that the following hierarchical sequence be followed in addressing hazards associated with a product’s use…