In this study, the dynamic buckling phenomenon of a simple column including material plasticity was examined in detail using a finite element (FE) analysis. The analysis revealed the relationship between impact velocity and a higher order mode of buckling. The result indicates that it is necessary to introduce a numerical imperfection, representing a higher order buckling mode under a given velocity, in order to simulate dynamic buckling accurately. It has been known that crash problems do not accept a sensitivity analysis because of their nonlinear history curves. A new approach to apply a sensitivity analysis to dynamic buckling problems including material plasticity is presented, which treats a higher order buckling eigenvalues. This method can indicate the most effective location to modify in order to increase the buckling strength of vehicle body structures. The analysis results also show that the impact induced wave propagation has a large effect on dynamic buckling modes of the structure, which can hardly be observed in physical experiments. (A)
Abstract