Coupling analysis method for the construction tensioning simulation process of flexible cable structures

Flexible cable structures have been widely used in buildings such as large stadiums and exhibition centers due to their significant mechanical advantages. Flexible cable structures need to be formed by tensioning. However, during the tensioning process of flexible cable structures, the system exhibits a geometrically variable state due to insufficient stiffness, posing significant challenges to its tensioning simulation analysis, especially for large-span cable structures. Current research on tensioning simulation methods for such structures primarily focuses on the nonlinear finite element method (NLFEM) and the vector-form intrinsic finite element method (VFIFE). However, nonlinear FEM is prone to matrix ill-conditioning and iterative non-convergence problems, and VFIFE has great difficulty in conducting collaborative tensioning analysis of cable structures and supporting structures. Furthermore, difficulties exist in determining the initial state of cables during the tensioning process of flexible cable structures. Therefore, this paper proposes a simulation method for the tensioning process of flexible cable structures that couples the NLFEM with the VFIFE method: The VFIFE is used to analyze the tensioning process of flexible cable structures, while NLFEM is employed to analyze the supporting structure to obtain the influence of the supporting structure's deformation on the tensioning process of flexible cable structures. Meanwhile, this paper also proposes a method for determining the initial configuration of cables. The applicability of the proposed method is first validated through experiments in relevant literature. Subsequently, this paper successfully simulates the tensioning process of Tongren Olympic Sports Center, a spoke-type cable-truss—one of typical flexible cable structure configurations, with a long span of 263.3 m and a short span of 245.3 m. It obtains the spatial positions of cable structure nodes, axial forces of cables and rods, lengths and tensions of tooling cables, as well as node deformations and member internal forces of the supporting structure during tensioning. The advantages and disadvantages of the two tensioning schemes are comparatively analyzed, thereby providing technical support for the final scheme of the actual project.