A theoretical model for the thermo-mechanical bending behavior of submarine power cables

Artikel i vetenskaplig tidskrift, 2027

Significant thermal load is generated in submarine power cables during power transmission, leading to thermal expansion and thermal stress in each layer of the cable structure. The resulting interlayer contact forces modify the contact state and slip behavior between the helical armor wires and adjacent layers, thereby influencing the nonlinear bending behavior of the cable. To address this, a theoretical model is developed to investigate the thermo-mechanical bending behavior of submarine cables. Based on thin rod theory and thick wall theory, an axisymmetric model under thermal loading is first established. A bending model that incorporates interlayer shear deformation is then formulated to characterize the nonlinear bending hysteresis response under combined thermal and bending loads. The axisymmetric and bending responses predicted by the theoretical model are validated against finite element (FE) simulations. The results show that the temperature rise increases the contact force between the armor layer and adjacent layers, which in turn raises the critical slip curvature and enlarges the bending-moment range in the hysteresis curve. Parametric analysis further reveals that a larger lay angle significantly reduces the stick stiffness and the moment range, whereas the critical slip curvature decreases and then increases as the lay angle grows. This work provides a theoretical framework and key insights into the intrinsic relationship between nonlinear bending behavior and thermo-mechanical effects in submarine cables.