Analytical study of effect of web opening on flexural behaviour of hybrid beams

Abstract

This paper present the analytical study of effect of web opening on flexural response of hybrid beams with various shapes of openings. Hybrid beam is used in structures to enhance their bending as well as shear strength. Fabricated beams are used when appropriate hot rolled section is not satisfying the design criteria. The beams are said to be a hybrid beams, when the beams are made up by means of the plates of not the same strength in flanges and web (mostly, fyf > fyw). In the present study, steel of nominal yield stress of 410 MPa and 250 MPa was employed as material for flanges and web, respectively. The analytical investigation has been carried using ANSYS software. The finite element model holds both the geometric as well as material nonlinearity. Failure modes, load–deflection behaviour of samples and stress concentration with deviation in size, shape and position of openings has been examined closely. From the parametric study, it has been observed that averagely there is a 40% increase in strength for the castellated hybrid beams over the homogeneous beams. Amongst the various shapes of opening, the performance of circular and hexagonal openings found to be excellent. The observed failure modes were similar in both hybrid as well as homogeneous beams and the predominant failure mode observed was the failure by the “Vierendeel Mechanism”.