Fatigue Failure of Rayon Tire Cord

Abstract

Tire-cord fatigue tests are characterized and interpreted in terms of the following parameters: magnitude and frequency of the cyclic stroke, average load, minimum load, temperature, and humidity. By varying one test parameter at a time, it is shown that the effects of creep and degradation are minimized by using a high frequency and a high stroke. The relative rating of two samples of rayon depends on the parameters of the test and on the modulus and twist structure of the samples. Fatigue breakdown is interpreted in terms of progressive fracture under localized strains occurring at the peak stress of the cycle. A comparison of the fatigue behavior of rubbers, metals, and tire cord suggests they may all involve the same basic process of crack growth.