The Study On Local-overall Buckling Of High Strength Cold-formed Thick-walled Square Columns Under Axial Compression

Compared with ordinary steel structure,the bearing capacity and economic performance of high-strength steel component is higher.With the high degree of industrialization,the quality is easy to be guaranteed,and the radius of rotary radius is greater than that of the opening section.It is in accordance with the axial compression member to carry out the cross section,the biaxial stability,the good torsion resistance,the overall stable carrying capacity higher requirements.Compared with the cold-formed thin-walled steel,the section size of the steel section is larger,the bearing capacity is higher,and there are many advantages in the application of high-rise steel structure.Due to the increase of strength,the thickness ratio is lower than the limit value.In addition,the cold bending of thick wall square tube cold bending effect and corner plate was made in the process of production parts the improvement of yield strength to some extent,this makes the generous than limit further reduce,local buckling component are more likely to happen.But as a result of steel plate parts in quadrilateral bearing state,the buckling stress after the panel is still can continue to grow,artifacts occurred after the local buckling does not immediately lose bearing capacity,but reduces the rigidity and whole stability bearing capacity of components.Therefore,it is necessary to relax the thickness ratio of the plate,and to improve the bearing capacity of the components and achieve the purpose of saving steel.In this paper,the following research is carried out on the local-integral correlation buckling performance of high-strength cold-bending wall-wall pressure components.(1)The advantages and disadvantages and application range of the calculation theory and method for the bearing capacity of the width and thickness ratio are analyzed.In this paper,the residual stress distribution law of the thick wall square pipe is summarized,and the residual stress equivalent method is put forward in ANSYS to meet the engineering precision.(2)Summarizes the cold bending steel considering the effect of cold bending yield strength calculation method,the our country the cold bending thin-wall steel structure specification GB50018-2002 in considering the effect of cold bending yield strength calculation method to calculate the cold-formed thick-walled tube considering the effectof cold bending yield strength.(3)The finite element software of ANSYS was used to simulate the axial compression member of the cold-bending thick wall,and the experimental results were compared with others to verify the correctness of the modeling method.In this paper,the numerical analysis of the axial compression members of 175 high strength cold bending wall is obtained,and the ultimate bearing capacity,buckling mode and load displacement curve are obtained.(4)The influence of yield strength,thickness ratio of plate and length of the component on the buckling performance of high-strength cold bending and thick wall axial compression members was analyzed.(5)According to the characteristics of the high strength cold-formed thick-walled square tube,revised formula related buckling of rectangular cross section method,and compared with the finite element results,proved that the modified proposals concerning the buckling method formula is more reasonable,can provide a reference for design work.