Numerical analysis on stress and displacement of tapered cantilever castellated steel beam with circular openings

Castellated steel beams are made from normal steel beams cut into half with certain pattern and re-jointed to increase its height. This action results in many shapes of openings in its web, one of them being circular. Circular openings of castellated beams can also be implemented with single fix supported structures, but if uniform shape is used, it will reduce its effectiveness. In this paper, adoption of tapered shape on castellated beams with circular openings as cantilever structures will be discussed. This study uses 150x75x5x7 and 200x100x5.5x8 IWF sections with variations of opening diameters, opening spaces, and span lengths. The steel has a yield strength of 400 MPa and the analysis runs with solid element 10-node tetrahedron using the finite element method, by observing Von Mises stress and displacement. Free-licenced software such as LISAFEA 8.0 and FreeCAD are utilized for analysing and drawing solid elements. The result shows that the optimum height of IWF section for 150x75x5x7 is 230 mm and for 200x100x5.5x8 is 318 mm between span lengths of 2 m to 3.5 m. It can be concluded that each of the span lengths has various optimum diameters and opening spaces to acquire the smallest stress and displacement.