Experimental Study On The Dynamic Response And The Lateral Torsional Buckling Behavior Of Steel Beams Under Lateral Impact Load

A series of explosion accidents and terrorist attacks and other emergencies in recent years has caused great threat to the peace of international community and the safety of production and life of everyday people. The explosion events not only had created the serious destruction in the partial scope to the construction, but also causing serious damage to the building, which is that the collapse of overall structure was triggered, due to impact of explosion projectiles and the upper falling objects even structure components lead to the instability of bottom component members and the bearing capacity failure of certain components owing to so large deformation. So both in safeguard structures and in industry and civil structures, study on dynamic response of components under impact loads, especially dynamic lateral torsional buckling(LTB) of components deserves particular attention.The research work and innovations in my paper lies mainly in the following aspects:1) Experimental study on the LTB behavior of steel beams under lateral impact loadExperimental study on dynamic lateral torsional buckling (LTB) response of steel beam under impact loads was completed for the first time in this paper, and then the buckling modes of the steel beams under different conditions were observed, and the impact and strain time history curves were recorded, and the effect of boundary conditions and impact energy and component sizes and other factors on the plane instability of steel beams under impact loading was investigated. The results showed that steel beams under static load are prone to instability deformation, but also under impact loading, and the residual deformation of the component may be mode superposition with local buckling; the lateral torsional buckling form of steel beams under impact loading dependent on each component itself and applied load conditions: the greater the flexural rigidity and the greater the impact energy, the more likely to higher order buckling modes generated; the anti-lateral torsional buckling capacity of fixed steel beams is better than clamped steel beams case in the same condition. 2) Simulation on the LTB behavior of steel beams under lateral impact loadBy the general-purpose finite element software LS-DYNA, the experiments were simulated considering the strain rate effect, and then the different buckling modes and the impact force time history curves and the residual deformation and so on were obtained. Comparisons with experimental results verified the feasibility and validity of ANSYS/LS-DYNA to simulate the dynamic instability of steel beams in order to provide reference for the future research.3) Comparative analysis for two constitutive models taking into account the strain rate effect on the structural dynamic responseDue to steel is a rate-dependent material, by three examples given in this paper using finite element software ABAQUS, constitutive models for the response behavior influence of components under dynamic loading has also studied, which both taking into account the strain rate effect include the Cowper-Symonds(C-S) and Johnson-Cook(J-C) models. The results showed that the C-S model is too more to contain the material strain rate effect.