This paper describes a methodology to evaluate the elastic lateral-torsional buckling strength of the H-shaped beam. The methodology is based on energy method with features of giving a displacement function to each of the top and bottom flanges and using multiple Fourier series with predetermined Fourier coefficients as the displacement function. With such displacement function, a high-precision closed-form strength equation for any loading condition can be obtained, and it is now possible to handle cases where the cross section is not uniform. To clarify the accuracy of the proposed equation, finite element buckling analyses are conducted.
Hiroshima et al. (Sat,) studied this question.