钢管填充混凝土后弹性与弹塑性屈曲分析

采用有限条法分析了方钢管填充混凝土后的弹性及弹塑性屈曲性能,考虑了钢板受均匀压应力作用和应力梯度变化两种工况,计算了钢板的临界屈曲应力,分析了残余应力对临界屈曲应力的影响.结果表明:当截面相对宽厚比低于30时,钢管内部填充混凝土并不能提高钢管的屈曲承载力;截面宽厚比超过30以后,随着截面宽厚比的增加,钢管内部填充混凝土后对钢管承载力的提高幅度越来越大,承载力提高幅度最大为空钢管承载力的2.58倍;并能有效提高钢板的抗弯屈曲承载力;残余应力的存在使得钢板在弹性和弹塑性阶段的屈曲承载力降低,残余应力越大,临界屈曲应力越低.

Elastic and elastic -plastic buckling behavior of SHS steel tube filled with concrete

A finite strip model for elastic and elastic-plastic local buckling is used to study the behavior of steel plates in SHS(square hollow section) steel tube filled with concrete.The steel plate subjected to compression and bending is analyzed,and the residual stress is also considered.The analytical result shows that the steel tube filled with concrete can not improve its buckling capacity when the width-to-thickness ratio is less than 30.When the width-to-thickness ratio is over 30,the core concrete can improve the buckling capacity of steel plate evidently with the increase of width-to-thickness ratio.The elastic buckling capacity of steel tube filled with concrete is 2.58 times that of hollow steel tube.The bending baring capacity of steel plate in the composite column can be improved.Residual stress of the steel plate will decrease the elastic and elastic-plastic buckling capacity.The bigger the residual stressis,the lower the buckling stressis.