Dynamic Response And Damage Analysis Of RC Special-shaped Columns Under Blast Loading

In the current stage of structural designs,structural design systems that considering accidental loads such as blast loads,high-speed impact loads,etc.are not perfect,and the main consideration is the regular rectangular column structures or components.The study of special-shaped columns such as L-shaped columns,T-shaped columns,and cross-shaped column structures or components is not deep enough.Compared to the regular rectangular column structures or components,the special-shaped columns have smaller cross-sectional dimensions,larger aspect ratios,and larger axial compression ratios,and the explosion resistance performance under the explosive impact loads will be different.In this paper,ANSYS/LS-DYNA general finite element software is used to study the dynamic response and damage of reinforced concrete special-shaped columns under the action of blast loading.The form of explosives is directly embeded in different positions of the structure to achieve the impact of blast load on the structure.The main research contents of this paper are as follows:1.Simplify the frame structure model of seven-story reinforced concrete special-shaped columns.The floors above the second floor are simplified as the load acting on the top of the second-story column.When the explosive lies on the different position of the first floor,the dynamic response and damage of the target special-shaped column for the reinforced concrete special-shaped column frame structures are studied under the ground explosive loads.In the numerical simulations,the changes of the factors varying with the time are specifically discussed,such as the dynamic and internal energy ratio of the surface,the acceleration,the effective stress and effective strain of the concrete element and the longitudinal reinforcement element,the nodal displacement of the longitudinal reinforcement and the longitudinal shear force of the target column,ect.2.When the explosive lies on the different position of the two floor,the dynamic response and damage of the target special-shaped column for the reinforced concrete special-shaped column frame structures are studied under the air explosive loads.In the numerical simulations,the changes of the factors varying with the time are specifically discussed,such as the dynamic and internal energy ratio of the surface,the acceleration,the effective stress and effective strain of the concrete element and the longitudinal reinforcement element,the nodal displacement of the longitudinal reinforcement and the longitudinal shear force of the target column,ect.3.The damage mode of the target column is analyzed after the failure of the reinforced concrete special-shaped column frame structure under the impact of explosion.The failure modes,damage levels,collapse conditions of the target column and the floor factors and azimuth factors that affect these damage indicators under various explosion conditions are summarized and analyzed.