Numerical Study of Castellated Beam with Stiffener - Case on Cantilever Structure

Abstract

A castellated beam is designed to increase the depth of the beam by slicing the beam web longitudinally in a specified form and re-unite both pieces using welding to obtain a higher flexural capacity of the beam. Due to the increase in cross-sectional height and the presence of openings in the web plate, some potential failures may occur, for example buckling of the web and stress concentration on the opening. Addition of stiffener on the web is useful to prevent those potential failures. This paper presented a numerical study of castellated beam with additional stiffeners which is applied on a cantilever structure using MSC Nastran software. The castellated beam was added by stiffeners placed on three different zones. There were stiffeners on the perimeter of opening, on the web between openings, and on the web of opening. The cantilever beam was subjected by a point load increased monotonically until ultimate condition reached. It was found that applying of the stiffeners on perimeter of opening will increase ultimate load up to 7.48 % comparing to the original castellated beam. On contrary, stiffeners on the web between openings and the web of opening will decrease the ultimate load within the range of 0.40% - 4.86 %. The beam stiffness will slightly increase because of these three types of additional stiffeners. Regarding ductility of the beams, adding of stiffeners on the castellated beam showed vary numbers. Overall, the stiffeners on perimeter of opening become an alternative to increase the performance of the castellated beam in term of the ultimate load, beam stiffness and ductility.