Effects of circumferential weld-induced imperfections on the buckling behavior of fabricated steel toroidal shells

Recently, toroidal shells have increasingly been used in engineering applications owing to their excellent loadresistance characteristics. Weld shrinkage during manufacturing leads to deviations from the ideal shell geometry, which is an inevitable imperfection of fabricated steel toroidal shells. To the best of our knowledge, there are no existing studies on the buckling sensitivity of fabricated steel toroidal shells to circumferential weldinduced imperfections. This study presents a modified technique for modeling circumferential weld-induced imperfections, which is employed in a geometrically and materially nonlinear analysis with imperfections (GMNIA) to investigate the imperfection sensitivity of two steel toroidal shells fabricated using different manufacturing processes. The weld imperfections applied on the finite element models were evaluated by modifying Rotter and Teng's weld depression profiles. The procedures for modeling the weld depressions and solving the critical load using the Riks method in ABAQUS are reviewed in detail herein. The obtained buckling results exhibited good agreement with Blachut's experimental results. Furthermore, parametric studies on the relationship between the buckling knockdown factors and the amplitude-to-shell thickness ratios of the imperfect shells revealed the superiority of the fabricated toroidal shells, which can be very beneficial for engineering applications.