Non-linear behavior of castellated beams consisting hexagonal and diamond openings using CFRP stiffeners

Abstract

A ‘castellated steel beam (CSB)’ is type of beam possessing holes in the web. The existence of such holes in the web of CSB makes the structures light in weight, cost-effective and contributes in reducing the consumption of material. As the web of CSBs consists of openings, it gets subjected to stress concentrations and web post-buckling failure at opening edges. In order to prevent this kind of failure stiffeners can be used in the web portion of CSBs becomes essential. The stiffeners contribute in strengthening the CSB with reduction in deflection and increment in load carrying capacity (LCC). This paper focuses on analysis of CSB having ‘hexagonal and diamond’ openings without and with transverse ‘carbon fibre reinforced polymer (CFRP) stiffeners’ of varying thicknesses (viz., 1.4 mm, 2.8 mm, and 4.2 mm) using Abaqus software based on finite element. Analysis is performed considering ‘two-point’ loading till the CSB fails showing the deflection more than its maximum permissible limit. Results indicate that the ultimate load carrying capacity (ULCC) of CSB consisting diamond openings with CFRP stiffeners of different thicknesses increases by a mean value of 17.77% while deflection reduces by a mean value of 5.66% when compared over the CSB consisting hexagonal openings. The software results get validated with results of experimentation. Study concludes that using CFRP stiffeners in CSB significantly increases its ULCC and reduces deflection. Further, the performances of CSB consisting ‘diamond openings’ are superior when compared over CSB consisting ‘hexagonal openings’ provided without and with ‘CFRP stiffeners’.