Research On The Overall Buckling Behavior Of Stainless Steel Build-up Columns Under Axial Compression

ABSTRACT:The key advantages of stainless steel structures are their remarkable corrosion resistance, which can offer a fundamental solution to the long term corrosion problems for carbon steel structures, raising their promising prospect in structural engineering applications. In view of the disparities in material properties and residual stress distributions between stainless steel and carbon steel sections, the buckling capacities of welded structural stainless steel members may differ significantly from carbon steel ones. The majority of the previous research on structural stainless steel has focused on the behavior of cold-formed sections. So far, far less experimental work have been carried out on welded stainless steel sections, which may be more suitable for meeting the strength requirements of heavier load bearing applications. There is currently no design standard for structural stainless steel in China;The use of stainless steel in structures is thus limited. This research focuses on built-up sections. By means of a considerable amount of experimental tests and numerical results, combined with the theoretical research on structural stability problems, the overall buckling behavior of welded stainless steel members under axial compression were investigated. The following three sections were covered in this dissertation.(1) Overall buckling tests on a total of17welded austenitic stainless steel columns and17welded duplex stainless steel columns with I-sections and box sections were conducted. Relevant data curve of welding austenitic and duplex stainless steel column and buckling modes had been obtained. Analysis results show that the decrease of ultimate bearing capacity of the specimen is roughly followed with the increase of column length and the increase of slenderness ratio, which conforms to the theoretical derivation result of steel structure.(2) After comparing the test data with the current domestic steel structure specification and the European stainless steel structure code, The results showed that the specimen test data is higher than that in the design of the corresponding curve data of the European standard, class b and class c curve in Eurocode3is designed relatively conservative, while the domestic steel structure specification did not meet the requirement of the stainless steel design, the specific stainless steel structure specification need to be prepared.(3) Based on the obtained experimental results, finite element models were generated and carefully validated, considering relevant influence factors such as initial defects and residual stress. After calculating, the yield modes of the specimens in finite element model were similar with that in the tests. Through model calculation, the trend of load displacement curve obtained from the model and test load displacement curve were the same. By means of analysis of finite element calculation results and test data, the reasons of differences were obtained. Differences were mainly caused by loading eccentricity, bearing constraint conditions and model error.