FACTORS AFFECTING THE FATIGUE LIFE AND FRACTURE AREA MACROMORPHOLOGY OF NATURAL RUBBER

ABSTRACT The service life of rubber products lacks a comprehensive evaluation of the factors that influence rubber fatigue life and an accurate prediction of their fracture behavior. To address this gap, we developed a protocol to investigate the working conditions that affect the fatigue behavior of rubber and document changes in the fracture area during its fatigue life. We subjected natural rubber specimens to various fatigue tests under changing conditions, including temperature, deformation, aging, sample geometry and frequency. For each experimental setup, we conducted a detailed examination of the fracture area, recording the rate and direction of crack propagation. Our observations revealed that the applied load within a dynamic deformation range substantially impacted fatigue life, providing valuable insights into the effects of these factors on material behavior. Furthermore, our macromorphological analyses unveiled distinct characteristics of crack propagation rates and directions associated with each factor at different stages of the fatigue life of the rubber samples. Additionally, the surface temperature elevated as deformation levels increased, highlighting the need to consider this factor in conjunction with geometric, mechanical, and environmental influences on rubber fatigue life. The combined effect of these parameters has the potential to either extend or shorten the fatigue life of natural rubber.