Fatigue of Rubber

Abstract

Abstract The long-range elastic properties of rubber suit it ideally to dynamic service applications. Vibration isolation, suspension, and force transmittal are examples of such uses of rubber compounds. Common examples illustrating these uses are isolation devices of all types, e.g., motor mounts, torsion, shear and compression springs, and tires—just to name a few. While fatigue failures may occur under static loads, they are generally accelerated by cyclic stresses. In most applications of rubber, a failure is critical in that the device depends for its functioning on the properties of the rubber and ceases to function when fatigue or other types of failure occur. Examples of fatigue failures are groove cracking in tires, tread and ply separations in tires, failures in torsion springs and motor mounts, etc. This review is concerned with fatigue of rubber under conditions of dynamic stress. Two specific areas are treated, the case where frequency of stressing is low enough and the samples are small enough that heat generation is not an important factor in failure and, to a lesser extent, the case where heat generation due to large samples and high frequency load application builds up temperatures which contribute to failure. Both of these cases of fatigue failure are encountered widely in service. For example, the first is found in vibration isolation devices such as motor mounts, and the latter in the shoulder area of heavy duty tires.