Lateral buckling of thin-walled members with shear lag using spline finite member element method

Based on the displacement variational principle, a general method, called the spline finite member element method, is developed for lateral buckling analysis of thin-walled members. A transformed B3-spline function presented in the paper is used to simulate the longitudinal warping displacement field along the cross section of the thin-walled member. The analysis takes into account the effect of shearing strains of the middle surface of walls on the buckling, which reflects the shear lag phenomenon. Compared with the results from classical theory and other methods, the numerical results proposed in the paper demonstrate the versatility, accuracy and efficiency of the proposed method. The fast convergency, shown in numerical examples, predicts the reliability of the results.