In this paper, the influence of strain-hardening on the ultimate behaviour of aluminium beams made of rectangular hollow sections (RHS) and subjected to non-uniform bending is investigated by analysing different aluminium alloys. The strain-hardening behaviour is related to the Ramberg-Osgood exponent of the constitutive stress-strain law of the material. A wide parametric analysis has been accomplished referring to both cooled, heat-treated and naturally-aged alloys. The results of comprehensive regressions analyses fitting the results obtained from numerical FE models are presented. Therefore, the main outcome of the work is the proposal of empirical relations for the prediction of the ultimate behaviour of RHS aluminium beams, accounting for the flange slenderness, the flange-to-web slenderness ratio, the non-dimensional shear length and the Ramberg-Osgood exponent. The proposed mathematical relationships allow a quick estimation of the ultimate non-dimensional flexural resistance and both total and stable part of plastic rotation capacity.

通过分析不同的铝合金，研究了应变硬化对矩形空心截面（RHS）制成的铝梁承受非均匀弯曲的极限性能的影响。应变硬化行为与材料的本构应力-应变定律的Ramberg-Osgood指数有关。关于冷却，热处理和自然时效合金，已经完成了广泛的参数分析。提出了从数值有限元模型获得的结果进行拟合的综合回归分析结果。因此，这项工作的主要成果是提出了经验关系式，用于预测RHS铝梁的最终性能，考虑了法兰的伸长率，法兰与腹板的伸长率比，无量纲剪切长度和Ramberg-Osgood指数。所提出的数学关系式可以快速估算最终的无量纲抗弯强度以及塑料旋转能力的全部和稳定部分。