Influência do comprimento na capacidade resistente de perfis de chapa dobrada a frio sob flambagem distorcional

Abstract

In the absence of a calculation method recommended by standard NBR 14762 (ABNT, 2010), research has sought to develop a simple method for obtaining the critical elastic stress associated with the distortional mode in cold-formed steel members. Many of the methods developed have difficulties in determining these critical elastic stresses. In view of this, some studies have used the critical length associated with the distortional mode to assist in the determination of the distortion critical elastic stress. In this sense, in view of the relevance of the length in determining the elastic stresses, this work aimed to verify the influence of the length of the profile in determining the resistant capacity of cold-formed steel members, under distortional buckling. To this end, equations were defined for the critical length associated with the distortion critical elastic stresses of profiles with C cross section stiffened under centered compression and simple flexion using Artificial Neural Networks. The equations showed good correlation with profiles whose experimental and numerical results are available in the literature. In addition, it was analyzed how the influence of length occurs in determining the compressive strength associated with distortion buckling. For cold-formed steel members under compression, the length only influences the resistant stress in profiles whose reduced slimness index is greater than 0,561.