Abstract
Silicone rubber (SiR), widely used in high-voltage cable accessories, is subjected to cyclic mechanical stress arising from operational expansion and contraction, which may affect material properties, performance, and effective service life of the cable systems. In this study, we have examined how variable mechanical stress at ambient temperature influences stress relaxation of two high-voltage SiR grades used in commercial slip-on terminations, particularly within the elastic, elastic-plastic transition, and plastic stress levels. SiR materials were subjected to both constant and cyclic mechanical stress, and their respective material behaviour were analysed. The stress relaxation response was examined for samples strained at various magnitudes for 24 h. Different compression levels were utilized to target the elastic, transition from elastic to plastic, and finally, plastic regions. The investigations revealed that cyclic mechanical stress subjected to SiR was dependent on material hardness. The level of mechanical stress affecting the rate at which stress relaxation