Nonlinear dynamic behavior of a guyed mast with unilateral cable constraints

Guyed towers are slender vertical structures anchored by stay cables, widely employed in engineering applications for their ability to reach great heights with remarkable structural efficiency. Due to their inherent slenderness and the complex interaction between the cable system and the central mast, these structures exhibit highly nonlinear structural behavior governed by geometric effects. The cable system provides lateral restraint and is particularly efficient when subjected to tensile forces. This study investigates the nonlinear dynamic response of a guyed tower subjected to base excitation. The structure is modeled as a simplified discrete three-dimensional system with two degrees of freedom. Special attention is given to the modeling of unilateral contact in the cable system, which allows the cables to carry only tensile loads. This constraint introduces a critical boundary condition that significantly affects the overall stability of the tower. The results clearly show that accounting for unilateral contact leads to a considerable reduction in the tower’s critical load and strongly influences its resonance curves, time histories, and phase portraits. These findings highlight the essential role of incorporating both geometric nonlinearities and the unilateral behavior of the cable system from the earliest design stages to ensure accurate and safe structural analyses.