Analytical solutions attempt for lateral torsional buckling of doubly symmetric web-tapered I-beams

The elastic lateral torsional buckling behavior of doubly symmetric web tapered thin-walled beams is investigated in this work. For the purpose, a non-linear model is developed in large torsion context according to a new kinematics proposed model. Firstly, the elastic equilibrium governing equations are carried out from the stationary condition. Secondly, the Ritz’s method is deployed in order to derive the algebraic equilibrium equations. From this system, an analytical formula is proposed for the lateral buckling strength of web tapered beams in function of the classical stiffness terms, the load height position and the tapering parameter. The proposed formula is simple and gives accurate results when compared to finite element simulations. For this aim some numerical examples are considered in the validation process.