Nonlinear analysis of castellated ISMB150 – I beam with hexagonal openings – A finite element approach

Abstract

The castellated beam with different web openings are mostly employed in construction since last decade due to its higher load bearing capacity with the mass lower than its solid counterpart and also economical. Though numerous simulation and experimental analyses have been made on castellated beam, the study on understanding the nonlinear behavior are very meager. The present investigation focuses on understanding the nonlinear behavior of the solid beam – ISMB150 and IC225 castellated beam – without and without diagonal bracing across the opening and the effect of fillet radius arrangements. The finite element model developed is analyzed using Hyper works 2017 with Opti struct solver with 3D hexagonal mesh model. The load vs deflection nonlinear results show that the load bearing capability of castellated beam IC225 beam increases upto 1.28 times compared to the parent solid ISMB150 beam. On providing the lateral stiffeners, the load bearing capability increases upto 28% compared to the ISMB150 and 15% compared to IC225. Due to the presence of sharp corners of the opening it is prone to crack and fail hence attempt had been made to check the variation of fillet radius in the corner. The Von-mises stress distribution shows that the failure occurs due to Vierendeel mechanism with yield occurring on the flange but without any failure on the web. The finite element analysis results show that the ultimate strength can be increased on providing the stiffeners which also reduces the deflection. The provision of fillet radius at the corners of the web openings also serve in reduction of the stress concentrations at corners.