This work presents and discusses numerical results concerning the elastic post-buckling behaviour and imperfection sensitivity of regular convex polygonal cross-section (RCPS) tubular beams buckling in local, distortional and mixed local–distortional modes, a topic currently lacking research. This study is carried out in the framework of Generalised Beam Theory (GBT) geometrically non-linear analyses, enriched with a branch switching technique, and takes advantage of the GBT intrinsic modal nature to shed new light on the mechanics underlying the post-buckling behaviour of these members. Due to the small half-wavelength of all the buckling phenomena addressed, only simply supported members under uniform bending are investigated. In particular, this work investigates the post-buckling behaviour and imperfection sensitivity of RCPS beams (i) exhibiting several wall numbers (6, 8, 10, 14, 20, 30) with distinct combinations of circumradius-to-thickness ratios (ii) having distinct lengths, and (iii) containing critical-mode initial geometrical imperfections with several amplitudes. Relevant displacement profiles and modal participation diagrams are provided along trivial and non-trivial equilibrium paths, in order to draw meaningful conclusions concerning the post-buckling behaviour of RCPS tubes under bending. For comparison and validation purposes, ABAQUS shell finite element results are also presented.

这项工作提出并讨论了关于正凸多边形横截面 (RCPS) 管状梁在局部、扭曲和混合局部扭曲模式下屈曲的弹性后屈曲行为和缺陷敏感性的数值结果，这是目前缺乏研究的主题。本研究是在广义梁理论 (GBT) 几何非线性分析框架内进行的，富含分支切换技术，并利用 GBT 固有的模态性质对后屈曲行为背后的力学进行了新的阐明这些成员中。由于所解决的所有屈曲现象的半波长很小，因此仅研究了均匀弯曲下的简支构件。特别是，这项工作研究了 RCPS 梁的屈曲后行为和缺陷敏感性 (i) 展示了几个壁数 (6, 8, 10, 14, 20, 30) 和不同的圆周半径与厚度比的不同组合 (ii) 具有不同的长度，和 (iii) 包含具有多个振幅的临界模式初始几何缺陷。沿着平凡和非平凡的平衡路径提供了相关的位移剖面和模态参与图，以便得出关于 RCPS 管在弯曲下的后屈曲行为的有意义的结论。出于比较和验证的目的，还提供了 ABAQUS 壳有限元结果。(iii) 包含具有多个振幅的临界模式初始几何缺陷。沿着平凡和非平凡的平衡路径提供了相关的位移剖面和模态参与图，以便得出关于 RCPS 管在弯曲下的后屈曲行为的有意义的结论。出于比较和验证的目的，还提供了 ABAQUS 壳有限元结果。(iii) 包含具有多个振幅的临界模式初始几何缺陷。沿着平凡和非平凡的平衡路径提供了相关的位移剖面和模态参与图，以便得出关于 RCPS 管在弯曲下的后屈曲行为的有意义的结论。出于比较和验证的目的，还提供了 ABAQUS 壳有限元结果。