Simulation and Experimental Analysis of Insulator Fracture Failure at Extremely Low Temperature

At extremely low temperatures, the bonding interface between the metal components of the transmission line insulator and the cement adhesive is affected by the huge temperature difference and the extremely low temperature, resulting in structural fracture due to thermal expansion and contraction, which in turn affects the integrity and bearing capacity of the insulator. In order to study the principle of adhesive failure of insulators at extremely low temperatures, a simulation model of disc suspension insulators was established. The stress and strain of insulator metal accessories and the internal thermal stress of insulators in low-temperature environments were simulated and analyzed, and the mechanical strength and size change tests of insulators in different low-temperature environments were carried out. The results show that the extremely low temperature will increase the failure strength of the insulator metal attachment, but the plasticity and toughness will decrease and the brittleness will increase. If there are defects in the ball head and rod of the insulator steel foot during the casting process, brittle cracking may occur under the ultimate bearing capacity, resulting in a fracture of the steel foot. The volume of cement adhesive for insulators shrinks with the decrease in temperature, resulting in gaps in the internal bonding interface of the insulator, causing the internal structure of the insulator to loosen, and the strength of the insulator at extreme low temperatures decreases significantly.