Some aspects of interactive dynamic stability of thin-walled trapezoidal FGM beam-columns under axial load

• Modification of the classical laminate plate theory (CLPT).
• A dynamic interaction of the global mode with the primary and the secondary local modes analysis.
• A two- and three-modal approach gave some unexpected effects.
• Phenomenon of combined inner resonance was suspected.
• An unsymmetrically postbuckling response of FGM plates was presented.

The present paper deals with a dynamic interactive response of FG beam-columns subjected to in-plane pulse loading when the shear lag phenomenon and distortional deformations are taken into account. The structures are assumed to be simply supported at the ends. In order to obtain the equations of motion of individual plates, the classical laminate plate theory (CLPT) has been modified in such a way that it additionally accounts for all components of inertial forces. Thin-walled trapezoidal FGM beam-columns are considered. A dynamic interaction of the global mode with the lowest primary local buckling mode and the secondary local mode has been analysed. Attention has been drawn to some unexpected aspects related to the fact that a two- and three-modal approach has been assumed in the analysis of dynamic interactive buckling.