Study On Local And Global Interaction Buckling Of Q690 High Strength Steel Welded Box Axial Compression Columns

With the continuous improvement of Chinese steel production technology,high strength steel is more and more extensive application in the modern engineering structures.Identity of the strength of the high strength steel has a larger increase,so comparing with the ordinary steel,the using of high strength steel can effectively reduce the weight and improve the utilization rate of resources.In addition,good social benefits and economic results will be achieved.However,with the decrease of the plate thickness and sectional area,high thickness ratio and slenderness ratio have different degrees of increase,and even beyond the limits of the existing specifications,which leading to the reduce of local stability and global stability of the high strength steel components.At home and abroad at present,the local and overall stability problems of ordinary steel structure components have a deeper understanding,but for high strength steel components especially for strength greater than 690 MPa,the related research are relatively few.In view of this,the study of Q690 high strength steel welded box axial compression column of local stability and global stability study is necessary.The main research contents of the paper are as follows:(1)using the ABAQUS finite element software established 270 different slenderness ratio,plate thickness ratio and section width-height ratio of the numerical model of compression of welded box column,and the initial defects of the components is taken into account in this model,material nonlinearity and geometrical nonlinearity factors impact on the bearing capacity of components,in order to study slenderness ratio,plate thickness ratio and section width-height ratio of welded box parameters such as axial compression member local-overall buckling effect of the ultimate bearing capacity.(2)the analysis of finite element simulation results can be summarized that slenderness ratio and plate thickness ratio of components are both important parameters which affect the ultimate bearing capacity of local-overall buckling of the welded box axial compression member;With the increase of plate width-thickness which the plate width is fixed and the plate thickness is varying,both of the ultimate bearing capacity of the component and the dimensionless ultimate bearing capacity go down.With the increase of slenderness ratio,the ultimate bearing capacity of the component and the dimensionless ultimate bearing capacity show obvious downward trend.However,the plate thickness influences the relationship between the section width-height and the ultimate bearing capacity a lot.This influence is rather than obvious when the plate thickness more than 5mm.(3)in this paper,on the basis of ultimate bearing capacity calculation formula,the author proposed the concept of local and overall stability coefficient,and made the multi-parameter regression analysis to make up the formula which contains three meaningful coefficients: plate thickness ratio and slenderness ratio and sectional width-thickness ratio.Then the author compared with the finite element analysis results,to prove that the modified formula can be applied to web high overrun the box of cross section thickness ratio of axial compression columns related buckling ultimate bearing capacity calculation.The results related to the high strength steel structure may provide theoretical support for the design and analysis.