Thermal buckling of aluminum conductors in submarine cables

Abstract

The conductor is a key component in submarine cables for power transmission. During the operation of the cable, the transmission of current results in an increase in the conductor's temperature. Due to initial imperfections caused by welding, the aluminum conductor at the joint may experience buckling failure under the compressive load induced by thermal loading. In this study, a finite element model is developed to investigate the thermal buckling of the wire in the conductor, and the model is validated against theoretical formulas within the elastic stage. The welding effect is considered in the finite element model, including the mechanical strength reduction, length, and initial deformation of the heat-affected zone (HAZ). The typical buckling mechanism of the conductor wire is analyzed, and a sensitivity analysis of the welding effect on the buckling behavior is also conducted. The results indicate that the conductor wire in the HAZ undergoes snap-through buckling under thermal loading during the plastic stage. This buckling behavior causes a sudden and significant increase in displacement and stress in the HAZ, which may lead to structural failure. Moreover, both the critical buckling temperature and critical buckling axial force are negatively correlated with the magnitude of the mechanical strength reduction, length, and out-of-straightness of the HAZ.