FINITE ELEMENT MODELLING OF AXIALLY LOADED MILD STEEL HOLLOW SPIRAL WELDED STEEL TUBE SHORT COLUMNS
Yasoja K.R. Gunawardena 1* and Farhad Aslani 2
1 PhD student, School of Engineering, The University of Western Australia, Crawley WA, Australia
2 Senior lecturer, School of Engineering, The University of Western Australia, Crawley WA, Australia
Even though spiral welded tubes (SWTs) offer numerous advantages compared to their alternatives, scarce experimental or numerical research has been conducted into the ultimate strength behavior of hollow SWTs in axial compression. This paper presents a parametric study that was carried out using non-linear finite element modeling (FEM) which investigated the behavior of hollow SWT short columns under concentric axial compression. Tubes with diameter (D) to thickness (t) ratios in the range 34-223 and steel strengths (fy) of 250-650 MPa were considered in the study which focused on the capacity, failure mode and load-displacement behavior of the SWTs. The spiral-weld seam shape was modeled explicitly in the analysis which also considered idealized geometrical imperfection shapes based on the first Eigenmodes. Good agreement was observed between actual and predicted failure modes while the ductility of the SWTs was observed to decrease with increasing D/t and fy. It was observed that orientating the FE mesh taking into account the spiral seam is critical for obtaining predicted behaviors comparable with those obtained experimentally.
Spiral-welded tube; SWT; finite-element; mild-steel; short-columns; hollow