Ultimate behaviour of RHS temper T6 aluminium alloy beams subjected to non-uniform bending: Parametric analysis

The aim of this work is the numerical assessment of the ultimate behaviour of temper T6 aluminium alloy beams subjected to non-uniform bending. An extensive numerical analysis has been performed by means of FE code ABAQUS with reference to RHS sections considering the typical range of variation of the geometrical parameters governing the ultimate behaviour of RHS beams under non-uniform bending. In particular, a wide parametric analysis has been carried out by varying the flange slenderness, the flange-to-web slenderness ratio and the non dimensional shear length accounting for the moment gradient. The ultimate behaviour of such beams has been investigated with reference to the material constitutive law proposed by Eurocode 9, based on the Ramberg-Osgood model. Particular attention has been devoted to the interaction between the different non dimensional parameters governing the ultimate behaviour. The importance of the investigated parameters on the non-dimensional ultimate flexural strength and on the rotation capacity of aluminium alloy beams is clearly pointed out. Successively, by means of multivariate non linear regression analyses, empirical relationships are provided in order to predict both the non-dimensional ultimate flexural resistance and the rotation capacity of RHS temper T6 aluminium alloy beams, starting from their geometrical and mechanical properties.