Fatigue life prediction of a piercing connector subject to breeze vibration and multi-field coupling

Abstract

Piercing connectors are widely used in power line erection. However, piercing connectors are susceptible to fatigue failure induced by wind load and multi-field coupling. Therefore, this study aims to predict the fatigue life of piercing connectors. First, the thermal-electrical-mechanical coupling model is created. Second, the electrical contact resistance (ECR) of piercing connectors is experimentally measured and converted into the heat generation rate (HGR) by the thermal equivalence method. Meanwhile, the breeze vibration load (BVL) of the conductor is calculated by the wind vibration theory. Then, the HGR and BVL are applied to perform the multi-field coupling calculation and fatigue life prediction. Finally, the effect of installation torque on the highest temperature, maximum stress, and fatigue life of piercing connectors is analyzed in detail. The results show that the ECR of piercing connectors decreases with the mounting torque, and ultimately tends to be stable. The highest temperature and maximum stress are located on the piercing blade, which is likely to become the failure origin. Within the allowable range of installation torque for piercing connectors, an optimal installation torque exists to minimize the maximum stress fluctuation and prolong the fatigue life.