Abstract The present paper focuses on the rotational capacity of H.S.S. steel sections; in particular, the influence of local buckling is accounted for by means of a new generalized cross-sectional slenderness parameter, which is used to characterize the cross-sectional rotational capacity, and, by extension, the available deformation capacity. Careful shell modelling of hollow section beams in bending was used, the numerical models being previously carefully validated against more than 50 bending tests. Extensive F.E. studies were consecutively performed, including many parameters such as various material grades, load and support arrangements, length-to-height ratios, etc. Specific attention was paid to the introduction of initial geometrical (local) imperfections, as they were shown quite influential on the rotation capacity. The paper then analyses the numerical results and points out the various influences of height-to-width ratio, shear, moment gradient, yield stress and length-to-height ratio on the available rotational capacity. In a second step, the rotational capacity demand vs. stability criterion is detailed, and related to the proposed generalized cross-sectional slenderness, which is shown to be more appropriate than the b/t ratios usually proposed in design codes. Finally, code-ready recommendations for new ways of allowing for plastic analysis in practical design following the proposed approach are given.

中文翻译：

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允许对管状梁进行塑性分析的基于细长的设计标准

摘要 本文重点研究高速钢型材的转动能力；特别是，局部屈曲的影响是通过一个新的广义横截面细长参数来考虑的，该参数用于表征横截面旋转能力，以及可用的变形能力。使用了弯曲中空截面梁的仔细壳建模，数值模型之前经过 50 多次弯曲试验仔细验证。连续进行了广泛的有限元研究，包括许多参数，例如各种材料等级、载荷和支撑布置、长高比等。 特别注意引入初始几何（局部）缺陷，因为它们表现得相当好对旋转能力有影响。然后对数值结果进行分析，指出高宽比、剪力、弯矩梯度、屈服应力和长高比对可用旋转能力的各种影响。在第二步中，详细描述了旋转能力需求与稳定性标准，并与提议的广义横截面细长相关，这表明比设计规范中通常提出的 b/t 比更合适。最后，给出了允许在实际设计中按照所提出的方法进行塑性分析的新方法的代码就绪建议。稳定性标准是详细的，并且与提议的广义横截面细长有关，这被证明比通常在设计规范中提出的 b/t 比更合适。最后，给出了允许在实际设计中按照所提出的方法进行塑性分析的新方法的代码就绪建议。稳定性标准是详细的，并且与提议的广义横截面细长有关，这被证明比通常在设计规范中提出的 b/t 比更合适。最后，给出了允许在实际设计中按照所提出的方法进行塑性分析的新方法的代码就绪建议。