| Compared with hot-rolled section steel,cold-formed thin-walled section steel has many advantages,such as high production efficiency,various section forms and good mechanical properties.The effective section method is used in the design of cold-formed thin-walled steel in the existing codes at home and abroad,but the calculation is complicated and the effect of distortion buckling is not taken into account.It was not until1998 that American scholars put forward the direct strength method with full-section performance,which made up the deficiency of the effective section method.In recent years,in order to improve the bearing capacity of members and facilitate the passage of pipelines and wires,stiffeners and openings are often installed in web,which makes the distortion buckling become the main buckling failure mode.In addition,cold-formed thin-walled steel column members are generally subjected to different degrees of eccentric load in practical structures,but the current research on cold-formed thin-walled steel column members is mostly concentrated on web-stiffened axial compression columns,however,there are few reports on the research of web stiffened columns with openings under eccentric load.Therefore,in order to solve the stability energy of web stiffened perforated column under eccentric load,the systematic research on this kind of member is of great theoretical significance for engineering application and the perfection and supplement of related codes.In this paper,finite element and theoretical analysis methods are adopted to carry out a relatively systematic research on the above problems.Firstly,the reliability of finite element simulation is verified by numerical simulation based on the existing experimental data.Then,the influence of different parameters on the bearing capacity,loaddisplacement curve and buckling failure mode of the members is analyzed,However,the difference of the bearing capacity of the member subjected to large eccentric load is small;the length reduces the bearing capacity of the specimen;the increase of the eccentricity has obvious influence on the bearing capacity;and the increase of the length reduces the slope of the load-displacement curve.The buckling failure mode of specimen changes with the length of stiffener and specimen.In general,the existence of voids does not change the buckling failure mode of members,but to a certain extent,it will reduce the bearing capacity of members and promote the degree of buckling deformation.In addition,the increase of thickness can significantly improve the bearing capacity.Based on the numerical simulation results,the bearing capacity improvement coefficient of the members with stiffened ribs on the web is obtained compared with the members without stiffened ribs on the web,and the curve fitting formula of the bearing capacity improvement coefficient is obtained through data fitting,and the axial bearing capacity of the members with stiffened ribs on the web is indirectly calculated.The commonly used at home and abroad of cold-formed thin-wall steel column under partial load,on the basis of the bearing capacity calculation formula of reference literatures holes exist on the calculation formula is introduced the method of reduction factor,component under the action of the partial load bearing capacity calculation formula for correction,apply to this article research the partial of the web with the stiffener under opening.A formula for calculating the bearing capacity of cold-formed thin-walled steel column is presented,and the reliability of the formula is verified by comparing the calculated value with the finite element simulation value.Figure [73] table [9] reference [55]... |
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