Structural assessment of segmental joints of wind turbine tower subjected to combined loads using finite element simulation

The wind turbine tower is an important component of the system that collects wind energy. The tower is built as a series of tapered pipes with decreasing thickness upward, which makes the joint connections play a significant role in the global structural integrity of the tower. A tower failure may trigger a global failure, as it might be followed by the rotor’s collapse, resulting in significant losses in maintenance expenditure. This study investigates the collapse behavior of the wind turbine tower with and without a bolt joint. The tower response was analyzed using the Finite Element Method (FEM) implemented in ABAQUS. Initially, a benchmarking analysis was conducted to verify the simulation procedures. After verification, numerical simulations were performed for the selected case configurations to evaluate the tower’s behavior under combined axial compression, shear force, and bending moment. Numerical simulation results show that the torsional loading of Loading Case 2 (LC2) significantly reduces the Load Proportionality Factor (LPF), with Loading Case 1 (LC1) having an LPF of 2.89 and LC2 having an LPF of 1.39, resulting in a weakening effect of torque on stability. Meanwhile, Material Nonlinear Analysis (MNA) and Geometric and Material Nonlinear Analysis (GMNA), which account for material plasticity and geometric nonlinearity, provide more realistic predictions with LPFs of 1.89 and 1.24 for LC1 and 1.95 and 1.29 for LC2. In addition, bolt pretension improved stress redistribution and structural stability, resulting in a more uniform load transfer within the jointed system. Therefore, these results contribute to the design and optimization of tower structures, emphasizing the importance of considering both material and geometric nonlinearities, as well as bolt pretension, in structural analysis.