Research Of The Elastic Flexural-Torsional Buckling Of Circular Hole Castellated Vaulted Curved Beams

The circular hole castellated vaulted curved beams have the advantages of light weight, high bearing capacity, economy, beauty and so on, so they are have been used in more and more practical engineering in resent years. However, as a kind of new-type members, the mechanical behavior of the circular hole castellated vaulted curved beams is more complicated than the common members. The stability problem includes flexural buckling and flexural-torsional buckling, but the critical load about the flexural-torsional buckling is usually lower than that about flexural buckling, so if there is not enough lateral bracing, the flexural-torsional buckling will occur first. Therefore, the research emphases of this paper is elastic flexural-torsional buckling of the circular hole castellated vaulted curved beams.The main analysis method in this paper is the finite element analysis by ANSYS. For the effects of the sectional characteristic and the open porosity to the flexural-torsional buckling have been researched deeply, the main considered parameter in this paper is curvature, and it is realized by fixing the arc length and changing the central angle.Firstly, this paper combines the formula of the critical axial force about the flexural-torsional buckling occurred in the solid-web vaulted curved beams under the action of the uniform radial load and the formula of the critical moment about the same beams under the action of the same end bending moment with the web equivalent stiffness formula in circular hole castellated straight beams separately. For the web equivalent stiffness formula didn't considered the effect of the curvature, this paper analyzed the effect of the curvature to the flexural-torsional buckling by finite element analysis, compared the finite element results with the result of the combinatorial formula, made regression analyze on the ratio and fitted the formula of the correction factor to the combined formula. Finally, the formula of the critical internal force under the action of the two special loads of the circular hole castellated vaulted curved beams.The internal force of the circular hole castellated vaulted curved beams is similar to that of the compression-bending member, and therefore, this paper made compression-bending correlation analyze on the ratio of the maximum axial force with the critical axial force under the action of the uniform radial load and the maximum moment with the critical moment under the action of the same end bending moment. Because there isn't analytical solution about flexural-torsional buckling of the curved beams under the action of the common load, this paper summarized the internal force judgement formula about the flexural-torsional buckling based on the result of the compression-bending regression analyze.