Research On Mechanical Behaviour Of Stainless Steel K-Joints With SHS Brace-to-CHS Chord

Stainless steel materials have the advantages of excellent appearance,attractive durability and better corrosion resistance,good ductility,easy maintenance and recycling in using life.Now stainless steel is no longer limited to the decoration engineering applied to the building,and will be applied to the main structures of the building or the key components of structures more widely.The welded joints of stainless steel,combined with the advantages of stainless steel itself and the characteristics of welded joints,clear transmission,convenient connection and steel saving,will be more and more popular in building structures.At present,the research on stainless steel hybrid tubular K-joints is still very scarce by the domestic and foreign scholars,especially the study of stainless steel K-joints with SHS brace-to-CHS chord,which restricts the application of stainless steel structure to a certain extent.Based on the above background,a combination method of the static experimental investigation and the finite element analysis was adopted to study the mechanical behaviour of austenitic stainless steel K-joints with SHS brace-to-CHS chord.The main contributions are as follows:(1)The tensile tests of 304 Austenitic stainless steel tubes were carried out.The mechanical properties and stress-strain curves of the K-joint specimen materials were obtained,which provided the reliable material parameter for the later finite element numercial analysis.(2)The static tests of 14 stainless steel K-joints with SHS brace-to-CHS chord were carried out,and the failure modes,ultimate bearing capacities and load-displacement curves of joints were obtained.(3)On the basis of the experiment,the ABAQUS finite element analysis software was used to model the specimens,and the further expansion of the simulation analysis was carried out after the accuracy of the FE models were validated.The influence of geometrical paprmeters including the brace width to chord diameter ratio ?,brace thickness-to-chord thickness ratio ?,chord diameter-to-thickness ratio 2?,eccentricity e,and overlap rate of overlap K-joints Ov on the failure modes and ultimate bearing capacities of the joints were systematically analysed.(4)Under the current design rules for calculating the bearing capacities of CHS K-joints,the applicability of the specifications was discussed by the method of replacing the brace member for K-joints with SHS brace-to-CHS chord.Further more,by modifying CIDECT formulae,the modified formulae for calculating the ultimate bearing capacities of K-joints with SHS brace-to-CHS chord were proposed.And the new formulae were proved to be appropriate for the ranges of geometrical paprmeters involved for K-joints with SHS brace-to-CHS chord in this paper.