Buckling Behaviour of Literally Tapered Steel Columns using FEM

الملخص

This paper presents the buckling behaviour of tapered columns which are widely used in structural engineering applications such as bridges and towers.  Buckling of thinned structural members subjected to compression forces have been studied for long time, and the buckling loads for different boundary conditions have obtained mathematically by solving the differential equations for each case considering the moment of inertia is constant through the entire section, while in case of non-uniform cross section, tapered columns are more complex compared to prismatic sections. In order to solve these problems, numerical methods become the suitable tools, such as finite integration or finite element methods, or any other methods. Finite element analysis is presented in this paper in order to investigate the behaviour of the buckling columns by including initial imperfections. The columns are lineally tapered w-sections with variable moment of inertia about strong axis, variable moment of inertia in weak axis or both axis were not considered. Abaqus-2014 software was used to analyse the columns and the buckling loads were obtained for tapered different ratios. FEM analysis consists of four models for each selected w-section in order to investigate the effects of tapered ratio on the buckling load.  Based on this investigation it is concluded that taper ratio significantly affects the critical buckling capacity for the same material properties and length. The exact effect depends on the boundary conditions and taper profile. The comparison of the buckling moment between prismatic section with the tapered section ranges from 4%-12% for W8×18 sections and 8%-20% for W14×30 sections