Finite element Analysis on Buckling Strength of Stainless Steel Circular Hollow Section Columns Under Concentric Axial Compression

Abstract

Stainless steel has superior corrosion resistance, fire resistance, and maintenance compared to carbon steel as a structural material. Although austenitic stainless steel (STS304) has mainly been used as structural steel material, lean duplex stainless steel, STS329FLD with lower nickel component (reduced to 0.5–1.0% in KS) has recently been developed as a substitute for austenitic stainless steel. Since duplex stainless steel is less costly and has excellent corrosion resistance compared with austenitic stainless steel, its use is expected to increase in the field of industry and infrastructure. However, there have been little data to apply this duplex stainless steel member to structural use. This paper presents an experimental and numerical investigation on the structural behaviors of austenitic stainless steel (STS304 TKC) and lean duplex stainless steel (STS329FLD TKC) circular columns subjected to concentrically axial compression. Test specimens were fabricated with four types of column lengths and slender ratios and were tested with both fixed ends. Duplex stainless steel (STS329FLD TKC) material showed higher yield stress and tensile strength than those of austenitic stainless steel (STS304 TKC). The results such as buckling shapes (local and global buckling) and ultimate strengths through additional parametric analysis were investigated and were compared with those predicted by current design codes [American Society of Civil Engineers (ASCE) and Eurocode (EC 3)] and by design equations of previous studies. Modified buckling equations were recommended considering the initial imperfection factor and limiting slenderness of two types of stainless steel circular columns and the accuracy of buckling strength prediction was improved. © 2020, Korean Society of Steel Construction.