Lateral-torsional buckling of fixed circular arches having a thin-walled section under a central concentrated load

摘要

When a thin-walled section arch is subjected to an in-plane central concentrated load, the load produces combined nonuniform axial compressive and bending actions, which increase with an increase of the central load and may reach the values, at which the arch suddenly deflects laterally and twists out of the plane of loading, and fails in a lateral-torsional buckling mode. The elastic lateral-torsional buckling of fixed circular arches under a central concentrated load has been a difficult problem to be solved, which is investigated in this paper. Accurate prebuckling analyses for axial compressive and bending actions produced by the central load are carried out. The analytical solution for the elastic lateral-torsional buckling load is derived using the principle of stationary potential energy in conjunction with the Rayleigh-Ritz method. The analytical solutions for the prebuckling axial compressive and bending actions and for the elastic lateral-torsional buckling load are compared with independent finite element results. It is found that they agree with each other very well, which validate the analytical solutions. In addition, the effects of load height, slenderness and in-plane boundary condition on the lateral-torsional buckling load are investigated. It is found that changes of the slenderness ratio, load height and in-plane boundary conditions have significant effects on the lateral-torsional buckling resistance of arches. This paper provides structural researchers and designers with a deep insight and useful analytical solutions for the lateral-torsional buckling of circular arches, and establishes a sound basis for investigations on the lateral-torsional strengths of fixed circular arches in the future.