Web Crippling Behaviour of High-Strength Aluminium Alloy Channel Sections under Concentrated Loading: Numerical Modelling and Proposed Design Rules

Two types of high-strength aluminium alloy (HA)—namely, AA-6086 and 7075-T6—have been developed and extensively used in recent years. These high-strength aluminium alloys offer advantages such as lower prices and higher yield strength than traditional alloys. The webs of aluminium channel members under concentrated loads are susceptible to web buckling failure, which restricts their applications. However, no research work has been reported that has evaluated the web buckling performance of high-strength aluminium alloy channel sections subjected to end-two-flange (ETF) loading, and the material characteristics of these high-strength aluminium alloys differ significantly from those of conventional aluminium alloys. This work addresses this gap by conducting a detailed numerical investigation. A parametric investigation consisting of 1024 models was performed using the finite element (FE) models previously developed for traditional aluminium alloys. A wide range of high-strength aluminium alloy sections covering varying web slenderness ratios, internal corner radii, bearing lengths, and aluminium alloy grades were considered in this investigation. It was shown that the latest design recommendations in the Australian and New Zealand Standards (AS/NZ S4600) and (AS/NZS 1664.1) were over-conservative when estimating the web buckling strength of such channel sections. Finally, new web buckling design equations for high-strength aluminium alloy channel sections were proposed through reliability analysis in this investigation.

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