Numerical investigations of compression members made of aluminium are presented and recommendations for reorganizing the buckling classes and curves are derived from these. Finally, the curves are compared with test results.

No abstract

As part of the ongoing revision of the Eurocodes, design provisions in EN 1999-1-1 on the buckling of longitudinally welded aluminium compression members have been subjected to a critical review. Numerical investigations were conducted because a need for improvement was identified. This part 1 of the paper describes the individual steps of the revision and the modifications discussed, which include the introduction of longitudinally welded members. Before going into the numerical investigations in more detail, previous observations are presented regarding buckling classes and plateau lengths. In part 1 of the paper, explanations of the numerical investigations are limited to presenting the modelling of the geometry, the mechanical properties and the imperfections as well as their respective variation in the context of the parametric studies. The results of the numerical investigations and the proposed design approaches will be presented in detail in parts 2 and 3.

As part of the ongoing revision of the Eurocodes, the regulations in EN 1999-1-1 on the buckling of aluminium compression members were also subjected to a critical review. This resulted in the need to revise the regulations for non-welded compression members and for longitudinally welded compression members. The introduction of a buckling class C for soft tempers and minor adjustments in the allocation of the individual alloys and tempers to buckling classes A and B can be understood as a fundamental change. The new allocation is presented and explained. The required buckling curve for non-welded columns made of materials of buckling class C was introduced in prEN 1999-1-1. In this context, minor improvements have also been made to buckling curves A and B. The curves are presented and compared with the results of numerical investigations. The comparison is done graphically as well as statistically (based on EN 1990, Annex D). For the design provisions of longitudinally welded aluminium compression members, a more extensive revision was necessary. The design concept was revised and switched to the use of separate buckling curves which are presented here. These curves are also compared with the results of numerical investigations.

As part of the ongoing revision of the Eurocodes, design provisions in EN 1999‐1‐1 on the buckling of longitudinally welded aluminium compression members have been subjected to a critical review. The numerical investigations described in part 1 of the paper were conducted because a need for improvement was identified. In part 2 of the paper, the main observations are presented in qualitative terms. Those observations are: the influence of the allocation of the materials to buckling classes, the influence of the imperfections plus the cross‐section geometry including the position and size of the HAZ within the cross‐section. Part 3 will conclude this paper by discussing the proposed design approaches in detail.