The influence of pre-tension on the fatigue durability of rubber with a single reinforcement layer

This study presents the results of fatigue tests on a composite material in which rubber is the matrix, while the reinforcement consists of a single layer of interwoven nylon cords arranged in a 0/90 o configuration. The tests were carried out using cyclic, symmetrical three-point bending of composite samples. This method, due to the negligible bending-induced stress, resulted in unidirectional cyclic tension in the sample. The loading was displacement-controlled and performed in two variants: without pre-tension and with pre-tension of approximately 10%. The failure criterion was defined as the point at which the force amplitude dropped to 50% of its initial value. Analysis of the results showed that the fatigue process is well described by the fatigue characteristic in the form of maximum strain in the sample versus the number of cycles to failure. Although the strain-time profiles differed between the non-pre-tensioned and pre-tensioned samples, the observed relationship proved to be universal. The application of pre-tension introduced a wider variety of mean values, enhancing the reliability of the obtained results.