An adaptive nonlinear simulation method for member buckling in lattice towers

To accurately simulate the force-deformation relationship of lattice tower members, this paper proposes an adaptive nonlinear simulation (ANS) method of member buckling behavior based on the physical model method. The proposed ANS method uses a combined buckling model (CBM) to simulate the plastic deformation behavior of tower members by integrating tension-compression and rotation springs, which has the advantages of clear physical meaning. Furthermore, to reduce the degrees of freedom of the entire structure significantly, an adaptive spring mechanism is introduced to adaptively add springs during the process of analysis based on the member stress state. Since the strong nonlinearity of the structure in the collapse process will lead to calculation instability, an adaptive implicit-explicit sequential solution scheme is incorporated into the framework of the proposed ANS method, which can ensure the calculation stability of the proposed method with higher efficiency. The proposed ANS method has been compared with ANSYS software and three full-scale tests of the lattice towers. The results show that the proposed ANS method can accurately predict the structural response, including the ultimate bearing capacity, failure location, and collapse process.