The sections) has been increasing inrecent times in aerospace,

The utilization of tapered beams (beams with varying cross sections) has been increasing inrecent times in aerospace, civil and mechanical structures. This is due to the fact that taperedbeams meet the aesthetic and functional requirements of the structure. Tapered beams are alsoknown to have high stiffness to mass ratio, better wind and seismic stability. Tapered beamsare generally chosen in order to be able to optimize the load capacity at every cross section.To be able to use tapered beams more often a balance between the fabrication cost andmaterial cost has to be present. A plethora of research has been done on doubly symmetric I-section and the mono symmetric T-section tapered beams over the past three decades. Scantyliterature is available on the structural behavior of tapered C-section. This present study aimsat understanding the structural response of tapered thin walled C-section as the taper ratio isvaried, the shear forces are considered negligible during this analysis. Analytical models toanalyze tapered beams have been developed by various authors over the past decades 1-7and will not be repeated here. There are no available classical methods to analyze taperedbeams 8. This study does not look into developing new analytical models but to study thestructural behavior of a tapered channel beam. The results obtained are based on finiteelement analysis.C-section beams originally were designed to be used in bridges but now are also used inaerospace, naval and in civil construction. In C-section beams the axis of bending does notcoincide with the centroid and the shear center lays behind the web, hence any bending loadapplied on the web or the flange would induce torsion.Thin walled beams with open and closed sections are often seen in aerospace applications.Thin walled beams when loaded in bending may fail in a bending-torsion mode coupling asthe torsional strength is relatively less when compared to the bending strength.With increasing taper the major moment of inertia had a linear decrease from root to tip9.Kim et al.2 found that in tapered cantilever beams the location of maximum stress is afunction of the loading type and the taper ratio. When a cantilever beam is loaded with aconcentrated moment at the free end the location of maximum bending stress depends on thetaper ratio and for an UDL loading the location of maximum bending stress is always at thefixed end. The lateral torsional buckling was found to be strongly affected by taper ratio4.Tapered beams with tapered flanges can resist stability loss in comparison to beams withtapered webs10. It was also deduced by Marques et al.11 that the location of failure was afunction of taper ratio and by varying the taper ratio the location of failure can be estimated.Taper ratio also decreases the amount of distortion, higher the taper of the section better theresistance to distortion and warping 12, 13. Tapering the beam further minimizes thedistance between shear center and centroid, ameliorating the critical load 14. With thechange in flange width while only tapering the web can increase or decrease the criticalloads14. The moment capacity at each section of tapered beams decreases from the clampedend to free end. The plastic hinge for a prismatic beam is formed at the fixed end, as the taperincreases the plastic hinge moves towards the tip 15. Effect of loading positions werestudied by Yeong and Jong16, loads were applied at the top flange, mid web and bottomflange and it was found that loads applied at the top flange reduces the critical loads incomparison to other loading conditions. The increment in critical loads due to taper aremainly dependent on boundary conditions, cantilevers show a significant improvementwhereas in simply supported beams the increment is trivial 17.Hence it is of utmost importance to study the effect of taper ratio. Taper ratio is defined asthe ratio of the tip dimension to the root dimension.