Measurement and Modelling of the Rubber Resilience based on Ultrasonic Nondestructive Testing in Tires

In tire industry, it is very crucial to evaluate physical and mechanical properties of rubbers which are used for production of tires, to ensure the quality of the final product. Resilience is an important property of a rubber, which cannot be evaluated through direct measurement in production cycle in this industry. Therefore, non-destructive ultrasonic testing, which has been used in many applications for examination of various material properties, can be used as an alternative approach for this purposes. In this study, the non-destructive ultrasonic testing method has been employed to investigate the resilience of nanoclay reinforced rubber compounds. By changing physical and mechanical properties of materials, ultrasonic wave velocities are changed. For this purpose, sixteen different samples of nanoclay reinforced rubber compounds with different formulations were prepared and both their resilience and the longitudinal ultrasonic wave velocity through them were measured. In the next step, using the relevance vector machine regression analysis, a mathematical expression for the rubber resilience based on the longitudinal ultrasonic wave velocity was developed, which was proven to be qualified with acceptable accuracy and generalization capability. The results of this research can be used for online evaluation of the rubber resilience in tire production cycle.