Modelos para análise da força crítica de flambagem em arcos circulares

Abstract

This research presents formulations for structural stability analysis of symmetrical arches with circular shape by determining the load related to the first buckling mode (critical load). Four loading conditions were suggested for analysis: uniform distributed load in the radial direction, concentrated load vertically in the middle of the span, uniform distributed load in the span direction and radial concentrated load. Three models were formulated for analysis, being a theoretical model obtained from the differential radial displacement equation resolution, a matrix model with eigenvalue analysis obtained from the Elastic Loads Method, and an approximate model using the Weighted Residual Method and the Galerkin Method. The theoretical model was developed for three-hinged, two-hinged, and hingeless arch analysis, while the others models were developed for two-hinged arch analysis only. To compare the results were assigned values for the arch's opening angle in order to characterize buckling coefficients, and performed numerical simulation with Finite Element Analysis software. The proposed models provide similar results for the analysis of two-hinged arches, and the rise-to-span ratio almost 0.3 allows high values for buckling coefficients evaluated according to the loading conditions, allowing the arch to be more stability efficiently. It also has developed a software, which enables the critical buckling load calculation of circular arches.