ANSYS/LS-DYNA-based Steel-concrete Composite Section Members Anti-blast Characteristics And Dynamic Response Analysis

Frequent explosive terrorist attacks have caused great harm to the social economy and people’s lives and property.Therefore,the anti-blast research on building structures has received increasing attention from engineers and technicians.Because steel-concrete composite cross-section members have many excellent engineering characteristics,they are more and more used in anti-blast engineering.In order to enrich the application research of anti-explosion technology,based on ANSYS/LS-DYNA finite element software,numerical simulations of several typical steel-concrete composite cross-section members in different explosive media fields are carried out in this paper.A more systematic study was made on the distribution of explosion pressure,the dynamic response of component explosion and its influencing factors.The main research work and main research conclusions of this paper are as follows:1.The main research work of this article(1).Summarized the basic principles and methods of anti-explosion numerical simulation based on ANSYS/LS-DYNA software structure.Briefly introduce the main functions and characteristics of ANSYS/LS-DYNA,summarize the basic steps and core processes of the ANSYS/LS-DYNA software numerical simulation method,and introduce the four major links of the ANSYS/LS-DYNA structural nonlinear dynamic analysis numerical simulation :Model planning,pre-processing,solving and control,post-processing.(2).Numerical simulations are carried out on the explosion dynamic response of several typical steel-concrete composite sections.In this paper,the ANSYS/LS-DYNA large-scale nonlinear dynamic finite element analysis software is used to numerically simulate the explosion dynamic response of typical steel-concrete composite cross-section members,mainly including: the numerical value of the circular steel tube concrete members in three different explosive media fields Simulation;Numerical simulation of concrete-filled square steel tubes;Numerical simulation of H-shaped steel-concrete components;Numerical simulation of cross-shaped steel-concrete components.(3).The analysis of the numerical simulation results and the influencing factors of the simulation results is the parameter analysis It mainly includes: analysis of the simulation results of component explosion impact pressure;analysis of the simulation results of component explosion dynamic response;analysis of factors influencing the results of component dynamic response(parameter analysis)-analysis of different media,different proportional distances,different cross-sections(forms and sizes),The influence of different material strength and different steel content on the dynamic response results of steel-concrete composite section members.2.The main research conclusions of this article(1).The peak positive pressure on the explosion face of the components in air,water,and soil: the peak positive pressure on the explosion face of the component in the soil medium is the largest,which is much greater than the peak positive pressure of the other two media.The peak of positive pressure on the explosion face of the component is the smallest,and the peak of the positive pressure of the component in the water medium is in the middle;the explosion face of the steel-concrete composite section column has positive and negative pressures,so two-way symmetrical reinforcement needs to be considered in the design of the component.(2).Characteristics of stress and displacement of components: For concrete-filled steel tube columns,the maximum value of equivalent stress and displacement occurs in the middle of the explosion face of the column;there are three types of component failure: bending failure,shear failure,and bending shear failure.damage.(3).The influence of the medium: the harder the medium,the more obvious the attenuation effect of the explosion,and the smaller the dynamic response of the column;(4).The influence of the section: the smaller the section size,the greater the dynamic displacement response of the component;the displacement response of the concrete-filled square steel tube column is greater than that of the concrete-filled circular steel tube column.This is due to the sharp edges and corners on the surface of the square steel tube concrete column,which is not conducive to the diffraction of the explosion shock wave.Therefore,the round steel tube concrete column has better anti-blast performance than the square steel tube concrete column;(5).The influence of strength and steel content: improving the strength of the material can improve the anti-knock ability of the component to a certain extent;Increasing the steel content can improve the explosion resistance of the components to a certain extent;(6).The influence of proportional distance: increasing the proportional distance can significantly reduce the maximum horizontal displacement response of the column,and the decrease is very fast.When the proportional distance exceeds 0.4 m/kg 1/3,the maximum horizontal displacement of the middle of the column The impact of gradually diminished.(7).Comparison conclusion of anti-blast performance of typical steel-concrete composite cross-section columns: comparison conclusion of component anti-blast performance under the premise of equal materials:concrete-filled steel tube columns are better than concrete-filled square steel tube columns;concrete-filled steel tube columns are better than H-shaped-Steel concrete column,H-shaped steel-concrete column is better than cross steel-concrete column,H-shaped steel-concrete column flange is better than web.