Experimental and Simulation Study on Fatigue Damage Characteristics of HNBR by HTHP Aging in Oil‐Based Mud Environment

ABSTRACT Hydrogenated nitrile butyl rubber (HNBR) elastomers are widely used in high‐temperature and high‐pressure (HTHP) corrosive environments, especially in the oil and gas sector. However, fatigue failure, which is often encountered in rubber components, remains a critical issue. In this paper, the effect of HTHP aging on the fatigue damage characteristics of HNBR in an oil‐based mud environment is investigated through experiments and numerical simulations. The experimental results showed that the elongation at break of the specimens decreased by 260% and the compressive stiffness increased with strain after high‐temperature and high‐pressure exposure in the oil‐based mud. Furthermore, tear tests showed that the rate at which the aged HNBR produced unit crack surfaces was significantly accelerated. Finally, the fracture and fatigue crack extension simulation results show the similarity between the damage evolution law of HNBR materials and the stress–strain curve of typical rubber materials.