Nonlinear Stability Analysis of Self-Supporting Roofs under Wind Loads Using Ansys Workbench Simulation

Abstract

Aims: The main objective of this study was to evaluate the nonlinear stability of a self supports roof with different spans subjected to wind loads. Specifically, this study  investigated the behavior considering geometric and material imperfections and nonlinearities, obtaining the buckling load before the structural system loses stability. Study Design: For this research, a computational approach was used, employing the finite element method to estimate the stability of self-supporting roofs under wind loads for different spans. The models were analyzed using eigenvalue buckling, and for non-linear buckling, a solution was found using the full Newton-Raphson method. Place and Duration of Study: Faculty of Engineering (postgraduate division), Universidad Autónoma de Querétaro (UAQ), between June 2024 and November 2025. Methodology: Four different scenarios were modeled in ANSYS Workbench, varying the length of the self-supporting roofs, using Shell181 elements for section MIC 240.The material used was ASTM A1008 Grade 33 cold-rolled structural steel. The critical load for linear buckling under wind loads was estimated by the CFE and INEEL wind design manual. Subsequently, in new models, stability was estimated considering imperfections, geometric and material nonlinearities, and the deformed configuration of the first buckling mode analyzed, in order to consider a degree of imperfection for each scenario. The critical load for nonlinear buckling was obtained, and the results obtained in the linear and nonlinear cases were compared. Results: The results for most of the scenarios evaluated showed that the critical load for nonlinear buckling is greater than that for linear buckling. Load increases of up to 275% were obtained, demonstrating that, for some load cases due to the pressures and suctions applied to the system, as well as the geometry of the arch, membrane effects occurred, increasing the stiffness of the roof. In addition, it was demonstrated that stability review is important for thin-walled structures, because even with an increase in critical load due to nonlinear buckling, in most scenarios the system becomes unstable before reaching the limit states for stress and deformation. Conclusion: This study suggests the importance of evaluating stability in self-supporting roofs, since instabilities can occur before reaching the design and service limit states. Likewise, it is necessary to evaluate linear and nonlinear buckling, since in some cases, depending on the geometry of the roof and the wind loads applied, the load capacity due to nonlinear buckling may be greater or less than that calculated using the linear method. The results obtained can serve as a basis for the development of a standardized procedure or even for the future incorporation of specific guidelines into technical standards, given that this type of review is not currently formally regulated.