Scaling effect of impact response for CFST components

Abstract

The plastic deformation and the strain rate effect caused by the dynamic impact load may cause the classical similarity law to no longer apply to the mutual derivation of the impact resistance between the geometrically similar concrete-filled steel tube (CFST) components. In this study, four CFST components with similar geometric sizes were designed. The effect of component size on the impact response indexes, such as impact displacement, impact force, and energy absorption of geometrically similar CFST components, was studied. It is concluded that the above impact response indexes of geometrically similar CFST components do not fully conform to the classical similarity law; that is, they have a scaling effect. The scaling effect of impact displacement is mainly due to the severe plastic deflection deformation in the mid-span impacted area of large-size CFST components. The scaling effect of impact force is primarily due to the slight normalized contact stiffness in the mid-span impacted area and the severe global stiffness degradation of the large-size CFST components. The scaling effects of the relevant impact response indexes studied in this paper are related to severe plastic deformation and minor contact stiffness of large-size components, and their scaling effect is more significant with the increasing scale factor, which is consistent with those for steel tube and reinforced concrete components. In addition, based on the simulation results and drawing on the classical similarity law expression, the scaling effect model of displacement and impact force for geometrically similar CFST components is preliminarily established, which can predict the calculated scale factor of impact response for CFST components.