The Study On The Buckling Of Stiffened Cruciform Members With Initial Defect Subjected To Axial Load

When the stiffened cruciform member is subjected to axial compression,it is likely to be torsional unstable.The flange of the stiffened cruciform member increases the torsional stiffness of the member.There is insufficient understanding of torsional instability of such members,and torsional instability damage is often ignored.At present,there are still few studies on the torsional instability of such members,and there is no clear definition of the bearing capacity in the design specifications.There is less research on the instability of the stiffened cruciform members subjected to axial compression with initial defects.In this paper,the theoretical and numerical simulation methods are used to analyze the instability of the stiffened cruciform members subjected to axial compression.The main contents are as follows:Firstly,the theoretical method is used to analyze the instability of the stiffened cruciform members with initial defect subjected to axial compression,and the bearing capacity of the members with initial bending defects subjected to axial compression in different instability modes is derived.The instability mode discrimination of the axial compression members is studied,and the influence of each section parameter on the torsional instability bearing capacity is analyzed.Then,the finite element software is used to numerically simulate the elastoplastic instability of the stiffened cruciform members with initial defect subjected to axial compression,and compared with the existing experimental results.The load displacement curve,the most unfavorable point,stress variation and ultimate bearing capacity are comprehensively investigated;the effects of various geometric parameters,geometric defects and residual stress on the instability behavior of the members are studied.Finally,a large number of finite element calculations are carried out,and the instability ultimate bearing capacity data of the stiffened cruciform members with initial defect subjected to axial compression are obtained.The fitting formula of the ultimate bearing capacity of torsional instability is proposed by analysis and calculation.