Some aspects of dynamic interactive buckling of composite columns

The static and dynamic problem of interaction of global buckling modes in compressed columns with complex open cross-sections was considered in this paper. Columns made of laminate composites were assumed to be simply supported at both loaded ends. A plate model was adopted in the analysis. Within the frame of the first order nonlinear approximation, the dynamic problem of modal interactive buckling was solved by the transition matrix using a perturbation method. Distortions of cross-sections and a shear-lag phenomenon were taken into consideration. A modification of the Kleiber–Kotula–Saran quasi-bifurcation dynamic criterion [Kleiber M, Kotula W, Saran M. Numerical analysis of dynamic quasi-bifurcation. Eng Comput 1987;4:48–52.] was proposed. A comparison of the proposed modification to the Budiansky–Hutchinson criterion [Budiansky B, Hutchinson JW. Dynamic buckling of imperfection-sensitive structures. In: Goetler H, editor. Proceedings of the eleventh international congress of applied mechanics, Munich, 1966. p. 636–51.] was presented for rectangular pulse loading.