Dynamic Progressive Buckling of Circular Tubes under High Speed Axial Impact Loadings

In this paper, Abramowitc and Jones model for analyzing dynamic progressive buckling of circular tubes under axial loading have been modified. In the improved model, the dissipated energy due to shortening of tube wall and the effects of inertia of previous folding layers on new one is considered. The mean crushing force and energy absorption, which is predicted by the theoretical model, has higher accuracy than the previous theoretical model. Based on the results of this paper, it is observed that the impact velocity and the mass of striker (neglected in pervious analytical models) are important in mean crush force and absorb energy of circular tube. Also in this research, it has been observed in the experiential tests that in most of the aluminum specimens, the high impact speeds, dynamic progressive buckling and in some samples in which the speed of impact was lower, dynamic plastic buckling happened. In this paper, final reduction in axial length, energy absorption and dynamic average crushing force in specimens in which dynamic progressive buckling has been occurred, is compared and discussed. Based on the results extracted in this thesis, it has been specified that theoretical results have acceptable consistency with experimental results.